Thursday, 8 December 2016

Painting a digital portrait step by step

Ivan, by Jeff Searle
Painting a realistic human face is a complex task that requires you to think of a multitude of things, so it can be helpful to introduce the process step by step. In this article I will talk you through the creation of a digital portrait painting (right), explaining the process as I go along. There are heaps of tutorials of this sort, of course, so I will try to justify adding another to the multitude by making mine better than the others :).

The techniques apply to painting any kind of face: male, female or humanoid alien, and much of it will apply to non-portraits too. In that sense it should be helpful as a general guide to making any digital painting. I will assume you have a reasonable knowledge of Photoshop or similar software*, and are painting with a graphics tablet. In earlier articles I have already discussed the anatomy of the head and the drawing of individual features so I won’t repeat all that more than necessary. I’ll refer to the person being painted as the ‘sitter’ but let’s face it, you are unlikely to have an actual person posing next to your computer – the person in my painting is imaginary and that’s fine too.

There are many ways to paint a portrait. No doubt some are more efficient and effective than others, but obviously you can experiment and paint however you want. These aren’t rules. Treat any tutorial as a set of guidelines to help you find your own way.

1. Preparation


To make a successful painting we need a decent idea. Put some thought into your concept, clarifying who is sitting, his or her character, and the mood you’re trying to achieve. Because this is a portrait tutorial we will focus on a head and bust, but you’ll need to consider your background too. Will the sitter be put against a neutral colour and texture, like a photographer’s backdrop? Will they be in a room, in a garden, in their workplace?

If you’re using photo reference, ideally it should be good quality with clear lighting, preferably from one main light source. The less suitable the reference, the more you will have to rely upon your own creative resources.

Some artists do only minimal preparation. Digital artist Daarken writes:

“When I start a painting I usually have no idea what I’m going to do or what it will look like... I have a basic idea of the angle that I want to paint, but that’s about it... I make a lot of changes throughout my painting. Not starting out with a tight drawing allows me to try different things more freely and to let ‘happy accidents’ happen.”
Digital Painting Techniques, 2009

Personally I like to know where I’m going, but inevitably some of your decisions will get made, and remade, as you go along.

Setting up


When you’re ready to start, create a new file in your software. When choosing a canvas size, you need to think about what the final output will be. Will your image be used for print or only on the web? A print image will need to be at higher resolution than one intended to be shown online. Consider painting your picture at a bigger size than the one it will be reproduced in.

Some artists start on a full-size canvas right away, with a dimension of say 1500 to 4000 pixels on the longest side. Others start small for the early roughing-in stages, say 500 to 800 pixels, then upsize later when it’s time to refine the image – this is good for less powerful computers and encourages a looser way of working in the earlier stages.

If you’re not sure what size your finished painting should end up, find digital paintings online to compare with. Also, learn from your finished work. If it looks pixellated you may decide you needed a higher resolution to get the results you wanted; conversely you may find you made it too big and can reduce it without loss. With a bit of practice you’ll get an idea about resolutions and file sizes.

I would avoid a white canvas: it is a bit less comfortable to stare at while painting, and it will distort your sense of colour, since colours look darker against white. Choose a neutral canvas colour. The canvas influences your skin tones, as it sits next to them and may partly show through the colours you paint on top of it, rather like in traditional painting. If you already have a colour scheme in mind, you could choose a colour that sits nicely with it, either harmonising with the intended foreground or contrasting with it.

For my painting, to help create a genial mood I decided upon light clothing and a light background, the head therefore looking relatively dark. I wanted a neutral warmish colour, giving me this exciting canvas:



Name your file, save it, and keep saving as you go along. It is a terrible thing to lose hours of work thanks to a butterfingers moment or an inopportune lunge by the cat.

A note on image resolution


The dimensions of an image are measured in pixels, e.g. a 600x800 image is 600 pixels wide and 800 high. The more pixels there are, the higher the image’s resolution, i.e. the more information the image can contain. A lot of confusion comes from two terms, ‘DPI’ (dots per inch) and ‘PPI’ (pixels per inch). These terms refer to printed output, not the quality of the digital image itself. The resolution of a digital image is simply its dimensions in pixels.

2. Sketch


I normally begin with a preparatory drawing. A sketch is a great way to plan out your framing and composition, and proves an invaluable guide while you’re painting. You can draw this directly on the computer or you can use traditional media and scan it in. Once you have your sketch on the computer, drag it onto its own layer in your Photoshop file. You may want to clean it up a bit – using the Levels to obliterate grey values is a neat way to remove any unwanted fuzz. Set the blending mode of the sketch layer to Multiply. This will turn the white transparent, allowing you to work on layers below the sketch and still see what you’re doing.

Alternatively you can draw your sketch directly in Photoshop. Simply create a new layer and name it, then using a small, hard brush, sketch the essential forms of your sitter, beginning with the basic forms, selecting the size, the tilt of the head and shoulders, then blocking in the features. It doesn’t really matter what tool you use as long as you get a useable sketch at the end of it, and it’s up to you how detailed the drawing is. As I say, personally I like to know where I’m going, so I prefer a precise, complete drawing as mistakes are easier to correct at this stage than they are halfway into a painting. Here is the sketch I drew for my example. I thought I’d keep the sitter – let’s call him Ivan – pretty straightforward:



Digital art is awash with fantasy girls, generically pretty and gazing at nothing as if they’d never had an emotion in their lives. The main thing for me was that my sitter, though imaginary, should look like a real person. For simplicity I’m going to leave the background neutral.

Note how the slopes of the shoulders act as directional pointers to his face.

If you want to know how to sketch a head, look at my earlier articles in this series on the head. In my example I have indicated a couple of plane changes but haven’t explored values at all, i.e. how light and dark different areas will be. You may prefer to make a monochrome (which means one single colour, not necessarily black and white) study or studies to explore that, or other aspects, before you start.

Take advantage of your medium. You can move your sketch around to test the framing and use tools like Warp or Liquify to adjust it until everything looks right. Flipping the sketch to see it in reverse often shows up problems you didn’t notice before. When you’re done, lock the layer as this will prevent you from painting on it by accident.

Again, save your work. You can save multiple versions as you go along if you like.

3. Establish your light


Painting is all about light. For this tutorial we will assume the sitter is lit by a regular diffuse daylight coming through a window. You must decide from the outset where your light is coming from. It’s best to keep this simple. Once you’ve chosen a direction, you will know which areas of the head will be in light and which in shadow.

The typical light for a portrait tends to come from the top left or right. That is the light we’ll use here. You don’t have to paint this in – these pictures are just for illustration. The planes that face the light source will be lit up, and the planes that turn away from it will be in shadow. We also need to think about any cast shadows, such as the shadow of the head on the neck and under the nose. Remember to think of the head as a three-dimensional block.



Define 1) the key light i.e. the principal and most intense light source, and 2) the fill light, which is less intense and comes from a different direction. You may also have 3) a back (or rim) light coming from behind, which will add a white highlight to the back of the head and, in our demo, also make the ears red because of the subsurface scattering.



The reason for having various light sources is to mimic what happens in nature, and make the painting more realistic. But you don’t have to use three. If it helps, you can try copying a light scheme from another painting.

Let’s go with a cool light and warm shadows.

Contours


We paint in two dimensions, but a human head exists in three: its forms project into space, with rises and depressions like a landscape. It may help you to create a new layer above the sketch and draw in some contour lines, a bit like a 3D mesh, to make you think about the head’s structure.



Even if you don’t actually draw in the contours, to depict three-dimensional form convincingly you need to be thinking of them while you paint. Like planes, they show you how the form will respond to light. Areas facing a light source will be lighter, areas turning away from it will be progressively darker.

4. Create a palette


Let’s get started. You need a palette of colours to work with. Put it on a separate layer so you can turn it off when you don’t need it. First you are going to need white and black, plus the primaries of yellow, cyan and magenta. From this basic starting palette you can mix the colours you need.

Make a basic skin tone using magenta and yellow, with a little white and black. Then mix a lighter tone for the lit areas, using the skin tone but with a tiny touch of blue for the cool light. 

For the shadow tone, darken the basic skin tone with a touch of black and of the complement: we have a cool light so add some red-orange to the shadow. Shadows are generally less saturated, so reduce the Saturation a little.

You will also probably need a variant of the flesh tone with some extra red in it, e.g. for the lips and cheeks. 



There’s no need to go crazy. A small range of colours will do for now. You could prepare an entire palette before you start painting, but in practice you will develop it as you work.

Remember, it can be tempting to go for strong colours to make the portrait ‘vivid’, but muted colours are more realistic. Avoid using the same palette every time, otherwise your paintings will all resemble one another! Don’t use plain black and white for lights and darks.

5. Block in the basic colours


The next step is to block in the basic colours. The principle is to work from simple to complex: we start very simple then build up layers of detail, to the level you want to achieve.

Create a new layer under the initial sketch and call it ‘flesh’. Stick with a large, hard round brush with a high opacity and use your new palette to block out the main skin colour using a medium tone. Keep it rough at this stage and focus on getting the colour in the right place, without being overly fussy about staying within the sketch lines. You could try using a brush below 100% opacity, to give the background a chance to show through a little.



Keeping to my plan of a light background and clothing, Ivan’s shirt is a warm grey.

Block in every basic colour in the image, not just the face: gradually bring up the whole picture together. Block in the hair and clothing on their own layers. Things like glasses and jewellery are best created on separate layers too so you can still work easily on the eyes and skin underneath.

A note on brushes


I am mostly using just the basic hard round Photoshop brush. Apart from blocking in I will keep it at low opacity, say 20+%, and build up colour gradually with repeated brush strokes. Some artists like to have an immense array of custom brushes, which is fine if that’s how they like to paint, but you don’t need them. If you don’t understand form, light and colour then no clever brush will save your painting.

6. Light and shadow


On a new layer or layers, paint the areas of light and shadow where they would naturally fall. Think about your light sources, the contours of the head, and the planes of the head. Remember the rule of thumb: warm light/cool shadow or cool light/warm shadow. Here I’m opting for the latter. You don’t need to be precise at this stage – just block the colours in with a large hard brush without zooming in.

Begin with the lighter areas. Begin with the basic flesh tone but mix a lighter version that fits into the lighting of the whole image. If you want the scene to be lit by a cool light, tend towards the ‘cool’ half of the spectrum.



Now apply the basic shadows, including cast shadows.



If the colours on your palette don’t seem quite right, at any time in the process you can adjust them.

Note that by ‘cool’ light I don’t mean ‘make all the lights blue’, though it could mean that – I mean shift them towards the cooler side of the spectrum. Same for the darks. Rather than use just a lighter shade of the flesh I’ve shifted the colour of the lights to be more yellow (heading towards the cooler shades, of green, etc) and the darks towards red. What I’ve done here is really subtle – you might want to emphasise it more.

Background


Think seriously about the background of the painting. Both sitter and background need to complement each other. Here we’re going to keep to a simple, neutral background, but even so, if we leave it as one solid colour it will look artificial. Work some lights and darks into your background and give it some texture. We can work on it a bit more later, but it’s good to establish our intended scheme of light and colour early on. My plan was to make both the background and clothing quite light, allowing the head to be the darkest area and keeping the whole painting fairly breezy.

To help the whole painting hang together, we can include colours from the flesh and clothing in the background, and vice versa. For example, the background could pick up the same colour as the fill/back light. I’ve included a hint of grey in the background and a couple of beige touches on Ivan’s shirt.



At some point you may want to reduce your sketch layer to about 20-30% opacity so it can serve as a guide without obscuring what you’re doing. Unless of course you want the line art to be part of the finished image.

A note on layers


Layers are one of the main advantages digital painting offers over traditional media, but it’s best not to over-use them. Too many layers in your file may slow down your computer and will complicate your working process. Try to keep basic elements like the hair and the eyeballs on their own single layer or on just a few layers within a subfolder. When you paint new elements, it’s a good idea to paint them onto a temporary layer first, then flatten it into the main layer when you’re happy – this lets you test how the painting looks ‘with’ and ‘without’, and makes it much easier to abandon something when it doesn’t work.

7. Facial colours


The human face is made of many colours, so for additional realism mix some colour variants, for example with extra red and yellow. Don’t be afraid of using complementary colours that you don’t normally notice in people’s skin, and experiment with blues, greens etc – the result will look natural once they’re blended in. Again, keep to fairly broad brushwork at this stage. Use new temporary layers until you’re satisfied.

Remember the three colour zones: faces tend to be more yellow around the forehead, red around the middle, and blue/green/grey around the mouth, though this is an extremely subtle effect and not mandatory.

In my example I’ve kept my colours conservative, adding some red to the cheeks, tip of the nose and ears, some yellow to the forehead, and some blue-grey to the chin:



Consider whether any colour will be reflected from the clothing onto the skin next to it.

I’m going to leave the treatment of Ivan’s clothing fairly rough. This is a reasonable strategy for a portrait, where the focus of attention must be the sitter’s face.

8. Consider amendments


Before you get into details, you may want to adjust and correct the proportions and layout of your portrait, for example by amending selections with the Warp or Liquify tools, or Edit > Transform > Distort. Make sure you’ve captured the expression you wanted, and flip the image again to check for problems.

The Warp tool allows you to select an area and click and drag the handles of the Warp grid to stretch or compress it in the direction you pull. The most versatile tool is Liquify, which you can use at any time to adjust your painting and correct mistakes. The advantage of working digitally is that if you go wrong or change your mind it’s easy to make changes. You can also easily afford to take risks that might cost you hours to undo in traditional media.

I decided I wanted to emphasise Ivan’s alert good nature a bit more, so I opened his eyes slightly wider and raised his eyebrows. I also adjusted his collar a little on the right so it balances up better. I’ll turn the sketch layer opacity back up so you can see better.



Now let’s check the proportions by flipping it:



Hm, the line of the shadow on his right cheek needs to come forward, so might as well correct that and flip it back:



If you started with a small canvas, now is the time to increase the image to its final pixel size, as we’ll be doing more detailed work from now on.

9. Features


It’s time to define the facial features. These will make a big difference to how your painting looks. We’ll do a first stage of work then refine them later.

Eyebrows


I wrote a very short tutorial on eyebrows here. Eyebrows are not thick lines drawn on the face – not normal ones anyway. They are composed of lots of little directional hairs. 

Eyes


Use lights and darks to model the structures around the eyeballs: you can refer to my full eyes tutorial here. Avoid drawing dark outlines around them if you don’t want it to look like the sitter is wearing heavy makeup.

I like to create a separate layer for the eyeballs underneath the flesh layer. Eyeballs shouldn’t normally look solid white. Instead, paint the eyeball in a greyish hue with a bit of the skin colour mixed in. Paint in a round iris and add the black pupil. Irises have dozens of tiny radial streaks in them – indicate these with a small opaque brush. They have a dark edge known as the limbal ring. We can refine the irises further later.

The eye shouldn’t look flat: it is a sphere set in a socket, so the corners tend to fall into shadow and are darker. The top of the eye curves away from the light and falls into shadow from the upper eyelid, so it will be darker there and across the top of the iris. The spherical eye affects the eyelids too, which will be lighter where they bulge out and darker in the corners.

Add a small cool highlight to each eyeball, placed in the direction of the main light source. This is very important for adding some life to your sitter. I’ve made a simple indication of the eyelashes too, which we will refine later.



Nose


You can refer to my full nose tutorial here. Define the basic structure of the main wedge of the nose, the tip and the wings.



Mouth


You can refer to my full mouth tutorial here. Block in the lips with a reddish colour, then apply some basic lights and darks to mould the mouth shape. The upper lip will be a bit darker.

If the subject’s teeth are showing, block those in – again, they will not be solid white, and will fall into shadow particularly in the corners and under the upper lip.

Remember that not everyone has ‘perfect’ features. Faces aren’t always symmetrical; women aren’t always beautiful; sometimes teeth are crooked or yellow or missing. Don’t try and turn everyone you paint into a digital robot. I’ve given my sitter a wonky tooth.



Ears


See my full ears tutorial here. So that I can demonstrate it, my sitter’s ears will glow with subsurface scattering, which means adding some bright orange to the ears.



Hair


Thus far we’ve simply blocked in the basic form of the hair. Hair can help you direct the viewer’s eye, especially if it’s long and flowing, so it needs to be organised. Even short hair shouldn’t necessarily shoot off in distracting directions. Don’t draw locks randomly – decide where they are going to go.

Strands of hair tend to group together in locks, so at this stage identify the locks and shade them like individual forms with light, half-tone and shadow. Keep it broad for now.



Your sitter may have facial hair. Ivan doesn’t have a beard but I fancied adding some stubble. You can do this by painting some grey around the chin or, like I did, you can use a speckled or textural custom brush.

Clothing


I don’t really need the sketch any more, so I painted in some of the details of the shirt then turned the sketch layer off. I’ve made the background slightly more emphatic too.

OK, now it’s starting to look like a portrait:



Don’t forget to keep saving. Again, you can make amendments as you go, and use your Photoshop tools to adjust forms and colours. It’s OK to make mistakes along the way. It’s digital, so they are easy enough to correct, and making mistakes is how you get better.

10. Blend the colours


The painting’s coming together. Let’s start to refine it.

Begin by blending together those rough colours on the hair, face and clothing. You will still need to go to your palette at times, but more and more you can simply sample colours from the painting itself. If you prefer to blend colours as you go along that’s fine of course – I’m just breaking the process down for teaching purposes.

Use a low (say, 15-30%) opacity hard round brush. Avoid the Smudge tool because, at its factory settings at least, it will take away the texture of your brush strokes. Use soft airbrushes with caution, as they give a very smooth finish that can leave your subject looking more like a porcelain doll than a human being.



I recommend saving the greatest detail and precision for the facial features, which communicate with us most, and preferring soft transitions for the edges of the hair and clothing. I can see Ivan’s hair needs more work in the latter regard. Keep adjusting your edges as you go along.

11. Develop the skin tones


Build up the lights and darks a bit more, using a lighter tone and darker tone than you used already. Think of how a change of plane can be marked with a change of colour and value.

Start with the lights and highlights. Normally highlights should be sparing. Avoid making them with pure white. Skin is slightly rough and diffuses reflected light, so highlights shouldn’t be too shiny-looking, unless the sitter is sweaty or wet. 

Now choose a darker shade of the skin darks and use it to deepen the shadows. A dark brown with reds and other colours in it reproduces the bouncing light seen on a real head. Don’t forget inside the mouth. Strong contrast between the lightest and darkest areas will create drama. You can use the Burn tool at a very low exposure to darken areas: when set to ‘midtones’ it darkens the skin to a deeper brown and when set to ‘highlights’ the darker additions tend to be very grey. Some may sniff at using Burn instead of mixing the colours yourself but it’s just a tool. Work at a low opacity so the colours can build up slowly and with subtle transitions.



You need to direct the viewer’s eye towards what they ought to be looking at. For example, don’t distract them by putting too much detail in the dark areas. Consider emphasising the contrast around the eyes, which are one of the most expressive and revealing features and you will want to draw the viewer’s attention to them. If you have a live model, don’t be afraid to depart from what exactly you see – creating a striking piece of art is more important than being literally ‘correct’. Artists always edit what they see towards an artistic purpose.

12. Other light sources


It’s time to incorporate your back and fill light into the painting. Create new layers for them, then (optional) flatten them into the main flesh tone layer once you’re happy. Three-point lighting is not compulsory: if an additional light source adds nothing or even spoils the picture, leave it out.

Back/rim light


Create a very light colour in a cool hue, to match the cool light/warm shadow lighting scheme. On a new layer, paint a fairly hard line down the shadow side of the head and shoulders. There will also be some subsurface scattering manifested as red/orange in the ear, which we blocked in already. Use layer opacity to adjust the intensity of the rim light.

Note that rim light won’t necessarily be at the same intensity all the way along the person’s form. It will be brightest on the up-planes facing the light, and less intense elsewhere.

Fill light


Add the fill light to the side of the head. Use a light colour: you could try a slightly coloured light for interest. I kept with a light blue. At low opacity, block in the general pattern of fill light, thinking about what direction you want to give it and where it will strike. Then work over it again to bring out some highlights. Use a low opacity, soft eraser to make adjustments. You are aiming for a nice, subtle effect.

When you’re done, you can experiment with the colour of the fill light if you want. Go to Image > Adjustments > Hue/Saturation, and click Colourise. This will allow you to introduce some colour and to experiment with brightness and saturation until you have something that is just right.



13. Polish the features


Let’s refine Ivan’s features to finish them off. The reason we didn’t do the features all in one go, in stage 9, is because we are trying to bring the whole painting along in stages. We have made important amendments since we first blocked the features in, and we need to have those in mind.

I’ll look at each feature in turn. Note that for a realistic painting the little details, though they may not seem like much in themselves, all add up and can take your painting to another level.

Eyes


The eyes are the most important feature, so let’s finish those first and take particular care over them. Paint the flesh of the tear ducts in red-pink and make it lighter in the centre where it’s moist. It’s easy to paint the bright highlight on the eyeball as a simple dot, but it can take other forms, the classic being an inverted white window i.e. the main light source reflected in the eye. There can be two or three highlights in different areas hit by the light source(s).

Spend time on the irises – make sure the limbal ring is dark, work on the streaks and add some other colours, for example blue eyes might also have grey, and yellow near the pupil.

Work on the eyelids, defining their shape and adding highlights. Eyelids have thickness, so remember the top edge of the lower eyelid, which may be a bit more fleshy in colour and possibly better lit. Add a light stroke near the inner corner of each eye.

On a new layer, carefully paint some eyelashes, using a soft round brush. Unless it’s a close-up, it’s enough to give a broad impression rather than try to paint every lash, so simplify them. The lashes tend to merge with the shadow under the upper eyelid to form a dark line. Paint them as blurry, simple shapes, a bit heavier at the base. Don’t draw them with identical length, direction and spacing, as this looks fake.



Women especially may be wearing makeup around the eyes.

Nose


Zoom in and see if you can make the nose more three-dimensional by working up the light and shadow, such as the shadow on the underside of the nose tip as well as the cast shadow upon the top lip. Keep the latter subtle or it will look like dirt or a moustache. You may want a highlight to the nose tip and down the bridge. The nostrils will be in dark shadow.

Earlier we added some fill light to the right-hand side of the face, so include those effects on the nose as well. Again, this will be more intense where the plane faces the light source, less intense elsewhere.



Mouth


The mouth still needs work. Remember the contours of the lips as you work. With a hard brush, add some light blocks of colour, following the curve of the form. The corners of the lower lip tend to be a bit less defined and merge into the flesh, so soften the transition there. Don’t forget the slight identations at either side of the mouth.

Shade the lips by applying darker shades to the down planes and areas in shadow. Make it a little darker at the centre of the lower lip. To adjust the entire lip area, create a new layer, paint in a colour then set the blending mode to Multiply. You may think the lips are too red or too dark, in which case add a new layer of skin tone then reduce the opacity until you’re happy with the adjustment.

Add some cool highlight to the top edge of the upper lip where it’s turned towards the light source, and to the lips themselves. Remember that specular light reveals a great deal about the material an object is made from. If your subject is wearing glossy lipstick, or their lips are wet, the surface will be more reflective and the highlights more sharp than on dry, natural lips (they will also be more intensely coloured of course).

If you want a bit of a moist look, using a light colour apply a series of small dots to the lips.

For the teeth, work up the shadow a bit more. The lines between the individual teeth are very subtle. Add some cool highlight where the teeth catch the light.



Hair 


Paint in more strands, adding extra lights and darks. Make sure there isn’t a hard line where the hair meets the forehead – this can create a ‘Lego hair’ effect.



Here’s how the whole portrait now looks:



14. Finishing touches


We’re very close now. Just think about any last adjustments.

Light


You may want to check, tidy up and refine your lights, darks and highlights, increasing them in places, decreasing them in others. Check you didn’t forget any. You won’t necessarily see these on a live model and might invent some purely to make the image easier to digest and the forms more explicit. For example a bit of reflected light on the chin, or a deeper shadow below it, will help to separate that form from the neck.

You could add a very subtle bit of rim light to the lighted side of the head too, for added interest and realism (because in the real world there are usually multiple light sources).

Colour


You may want to have a final play with colour balance, saturation, values and so on. Perhaps the skin is too saturated, the nose is too red, or a strong colour juxtaposition is distracting the eye. The best way to make these changes is to make a temporary layer or duplicate the layer you’re changing, make the adjustment, turn it on and off and try out opacities to assess the difference, and flatten it once you're happy with the change.

There are all sorts of ways in Photoshop to adjust the colours on a layer, such as using Colour Balance, or Curves to adjust a specific colour channel. I won’t try to list everything. Thanks to such tools, you can easily adjust the colours in your painting.

Details


You may want to add a couple of little touches of pure, or nearly pure, black and white to push sharp details. Remember not to overdo detail in places where it doesn’t belong. If your sitter is wearing jewellery, for instance, you probably don’t want it so meticulous and dazzling that the viewer looks at that rather than the person underneath.

Edges


Go through the painting, tidying up edges where appropriate and roughening others. Sharp, shiny edges may be fine on glasses or other objects, but you don’t generally want them on human skin as this looks artificial. In general, a too-sharp and perfect outline doesn’t look very painterly and may detract from the sense of realism.

Texture


Real skin is not smooth and perfect. If you look closely it has a rough surface, with spots, freckles, moles, scars and blemishes. Whether you paint this, and how far you take it, depends upon your taste and on your sitter: the complexion of a spotty teenager will need more attention than a fashion model’s beauty spot. 

On a new layer, dab on a few little marks, e.g. around the eyes, to suggest irregularities in the surface. Adjust the layer’s opacity and blending mode and keep it natural. You can use a speckled brush sparingly to recreate the porous roughness of human skin, though I haven’t done that in my painting.



Changes like these are generally best kept subtle. But if you paint subtle changes on a new layer then turn them off, you will see the cumulative difference they can make.

Use a hard brush to add a bit of roughness to your brush strokes on the face. Conversely, use a soft brush to soften any areas that look too rough, though you don’t want the finish to be overly polished and artificial.

Another idea for creating texture is to let your line art show as part of the final image, in a sepia or red tint and at low opacity, depending on whether you think it adds anything or suits your intentions.

Background


Cast your eye over the background and make sure it works. As I’m working with a darkish head with everything else underplayed, I’ve done a reverse vignette, fading out the outside edge, then increased the canvas size a bit to give the final image some room (giving me a canvas size of 2500 pixels wide by 3000 high). Also I’ve done some darkening behind the head and shoulders to bring out the rim light.

Final word


Take one last critical look at the piece, sign it, and save it. Here is my final painting of Ivan:



That was my guide to painting a digital portrait step by step. Obviously this is only one way of working. Other approaches are available, and you don’t have to do the steps in strict order. Get painting and find the way that works for you. If you use the same palette, the same light, and the same sort of sitter in every painting you do, they will end up looking identical and your body of work predictable. This guide is a starting point, not a rigid formula – my goal was to pull together the information in the two previous posts and show beginners how they might apply it all to an actual painting.




* If you need to learn about digital painting techniques you should try Matt Kohr’s website Ctrl+Paint. He has a huge and comprehensive set of free videos which will teach you just about everything.

Monday, 12 September 2016

Portraits in colour

Returning to the subject of the human head, let’s look at how to apply colour to painting a portrait. I am coming from the perspective of digital art, but most of the observations below apply for any media.

Colours of the skin


Beginners usually don’t realise how many colours there are in a person’s skin. A common mistake is to choose a basic flesh colour, then add white and black to create highlights and shadows respectively. 

Using this approach for a white person like me, you might end up with a palette that looks a bit like this:


This is basically a single colour gradient. Its lack of hue variation means the subject’s flesh will look dead, and the portrait boring.

Real skin is much more interesting. It can include blues, pinks, violets, yellows, greens and more. This holds less true for black people than for white people who have relatively translucent skin, but it is true of everybody to some degree. Look carefully at your own skin and you’ll see what I mean. This is before we consider colour reflected onto the skin from the environment, such as from brightly-coloured clothing, or from the light itself, such as the orange glow cast by a setting sun. So when you paint a portrait, by all means start with a base flesh colour, but remember to look for other, sometimes unexpected colours created by veins, hair, variations in skin tone etc. Three very simple suggestions might be:

  • A bit of blue under the eyes.
  • A touch of red on the cheeks, nose and ears.
  • A hint of green or purple in the shadows.

If we want, we can exaggerate these hue variations to make our picture more lively.

Below is a portrait of a young woman by Lucien Freud. I have picked out a few of the colours he used for the face (leaving out the eyes and hair).


This painting is in the realist tradition – a more radical or abstract artist like Picasso can enjoy using colour more riotously. Yet note how Freud has used yellows, reds and even greenish and bluish hues besides the brownish hues one might expect. These colours help create a really vivid, and indeed more realistic, portrait.

That said, the actual colours are less vivid than you might think. Here is a detail from Rubens’ portrait of his daughter, Clara Serena:


Rubens is a master of the ruddy complexion, and this strikes us as a very ruddy child indeed. But if we take a closer look at that vivid left cheek – see inset – we see that the colours are more muted than you’d think. The small second box is a colour sample from the cheek and it is certainly not bright red, more a dull terracotta. Assuming you are seeking realism, it is best to resist the temptation to use strong colours and to instead carefully build up the painting using muted hues. The vividness of Clara’s cheeks comes from the relative contrast of this muted terracotta with the even more muted colours around it.

Colour zones of the face


In light-skinned people, the face can be divided into three broad colour zones: white/yellow, red and blue-grey.


In the forehead there are relatively few surface capillaries, or blood vessels, making it a little more white or yellowish in appearance. It also tends to be slightly better lit, because it’s at the top. In the middle region of the face there are lots of capillaries full of red blood cells, giving the ears, nose and cheeks a reddish tint. And in the lower third, the chin and upper lip have a greyish or bluish tinge thanks to the hair follicles, and because it can be fractionally less well lit. This normally more affects men, but for women and children artists sometimes like to add green as a complimentary colour to bring out the lips.

Again this feature is more visible on white people than on darker people.

The three zones can be very subtle, but once you know to look for them you will spot them regularly. For example here is a pair of portraits by Rembrandt Peale:

Left: Portrait of Henry Robinson. Right: Portrait of Rosalba Peale.

You won’t find the zones in every painting, and your portrait isn’t wrong if you leave them out, but you should be aware they exist.


Creating a palette


Online you can find pre-prepared palettes – basically a set of swatches – for painting skin tones. For example here is a set made by Lauren K. Cannon for a DeviantArt tutorial series. You can save your own favourite colour combinations in Photoshop as swatch sets so they are ready to use again and you don’t have to repeat your work. 

Premade swatches can help get you started, but you can easily end up using the same set of colours for every head you paint, and it is misleading to think you can create a standard recipe for any object, given the multiple variables that influence colour. It is more rewarding to mix your own skin tones for each portrait.

You can create skin tones using a limited starting palette of the yellow, magenta and cyan primaries plus black and white.

Begin by finding a basic skin tone. Use the yellow and magenta to create an orange. As we noted above, skin has muted colours – if a colour looks too bright you can make it more neutral by mixing in a little of its complementary colour, so add a bit of cyan to your orange to mute it. Mix in dabs of white and (very sparingly) black to get the base skin tone you’re looking for. Now create lighter and darker variations. Here’s a palette I created:



On the left are the five starting colours. The next column shows the range of five tones I mixed, with the middle one serving as the base skin tone. The third column shows three extra colours for warmth and shadows. This would be fine to kick off. While painting we could add more mixes as we went along.

When mixing the range of colours you need, ask yourself what is the hue or local colour of the subject’s skin? Nobody is literally ‘white’ or ‘black’. Is it more reddish, more yellowish? What is its value – is it lighter or darker? How saturated or intense is it – people who are florid from years of booze and outdoor work will be more vividly coloured than an invalid who’s lain in a dim room for years. You don’t have to get all these colours exactly right before you start, of course. You can keep adjusting as you go along.

Try to think beyond clichéd assumptions. For example if you are painting a white European you may instinctively assume you need to paint them a light brown. In fact they may not appear light brown at all, since the local colour of a person’s flesh is affected by the light falling upon it. If they are standing with their back to a sunset they may be in very dark shadow with a bright orange glow. If they are lying on a bright yellow pillow, part of their face may be bathed yellow with the reflected light. If they are in a dark room they will be poorly lit and thus appear dark themselves.

An intense light source can blast out local colour altogether. A strong light source creates strong highlights and shadows; a gentle, diffuse light source creates gentle highlights and shadows.

Create swatches using the Mosaic filter


When you’re thinking about what colours to use there is a sneaky technique you could try. Find a painting whose colour scheme you like. Open it in Photoshop and use Filter > Pixellate > Mosaic to reduce the image to basic blocks of colour. You can choose the degree of pixellation. Here is an example using the Rubens image:



This simple process creates a kind of swatch palette you can use as inspiration for your own paintings.

Warm and cool in portraits


In the previous article we discussed warm and cool colours. We can apply the same principles to a head in a portrait. Pairing cool light with warm shadow, or vice versa as Lucien Freud did in his painting above, creates a nice contrast and livens up the picture. Traditionally, professional portraits tend to be painted in north-lit studios, as north light is less harsh than the direct sunlight that comes from the south, and this has led to a preference for cool light with warm shadow. Rembrandt’s method was to layer cool highlights, warm light, cool half-tones and warm shadows.



In practice, this broadly means that in a cool light you will have orange-ish shadows, and in a warm light you will have blue/purple shadows. Now, if you have a warm light source it doesn’t mean your shadows must be blue or purple, just that they should be a cooler version of the light. You have to consider the local colour of the object, i.e. the person’s head, and the temperature of the light source, and so on.

A couple of tips:

  • Colour changes on a portrait often take place where there is a change of light or plane, so consider alternating warm and cool at these places.
  • Changes of colour temperature from one stroke to another make things more interesting. Juxtaposing strong patches of warm and cool will help to make a particular bit of the painting grab the viewer’s attention.
  • Warm colours tend to jump forward a little more, so perhaps use them on nearer portions of the face and use cooler colours on portions that are farther away. Keep these shifts subtle.
  • Where skin touches skin or folds upon itself, it becomes warmer in colour. 

It’s up to you how intense you make your contrasts. Remember that by mixing colours with their complements we can create less brilliant, more neutral hues.

This interplay between light and warm is not just a technical trick – it makes a more believeable painting, and, at the risk of generalising, a more enjoyable painting. So being able to identify the temperature of colours is an essential skill.

Practicing skin-painting


3D art has introduced the idea of the texture sphere as a standard way of presenting how to paint different materials and surfaces. The idea is to take a particular material and imagine how it would behave when painted as a sphere. Instead of simply copying what is in front of you each time, you have to understand the material well enough to make it work in three dimensions, and to repeat the process from imagination when you need it. Digital artists can use them to practice, amongst other things, human skin.

In my illustration below I show three stages in the creation of a texture sphere for skin. I’ve done studies for three complexions: fair, medium and dark.

1) Draw a circle with the elliptical marquee tool and fill it with your base skin tone, then lock the pixels of the circle. This means you can paint in the circular area only and needn’t worry about keeping the edges neat.
2) Paint in the half-tones and shadow, using a hard brush at a low opacity (say 20%). You can get a very smooth effect very quickly using a soft airbrush but skin doesn’t have a perfectly smooth texture. Remember the highlights and shadows will be less saturated than the mid-tones.
3) Finish off with highlights – not too shiny, as it’s skin – and reflected light. In my examples below I’ve used a slightly blueish light for a cool highlight, and a purplish tint for a warm shadow. Add some texture, using white dots to imply the texture of pores.



We can go further by practicing different light effects. In the examples below, I augment each complexion with veins, green light, and a cast shadow from an imaginary second object:



Texture spheres are a great way to practice. Make some of your own.


Subsurface scattering


Painting is all about light, and light behaves differently depending upon the material it’s striking. To paint materials realistically you need to know about these effects and be able to reproduce them. A human being is not solid, like a statue, but has a luminous outside layer.

Subsurface scattering
Photo Davepoo2014, Wikimedia Commons
When light hits a partly translucent substance, various things happen. While some of the light reflects off, some of it gets absorbed by the substance, and is scattered around as it finds its way out. This effect is known as subsurface scattering and occurs with materials like wax candles, marble, paper and skin. Though it’s not normally obvious, skin is translucent, and subsurface scattering can give it a diffuse glow. Try holding your hand up to a bright lamp or sun and you’ll see the effect.

The effect occurs when you are looking at an object with a strong light behind it – if you’re in front of it with the light behind you, you will see it lit as normal – and is particularly noticeable on small objects like fingers, noses and the fleshy parts of the ears. In ears, fingers etc we see a bright and saturated red, an effect blocked by more solid substances such as the bones in the fingers. Even if your sitter is front-lit, you might observe a red tinted edge where light travels through the skin.

Here is a quick digital study I made of subsurface scattering affecting the ear:


And here is my attempt at a subsurface scattering texture sphere:


Note that black people’s skin absorbs more light thanks to its higher melanin content, so more of the light coming off it is reflected rather than scattered.

The classic oil painters built up their flesh in layers, and the paint, being translucent, would have a convincing fleshiness to it through several colours working at once. How can we reproduce this luminosity? As the light bounces through the shadow areas it makes them warmer and more saturated, particularly at the core shadow, so on a new layer try adding red-orange throughout the figure at the edge of the core shadow and adjust it using blending modes.

Edges


Edges mark the ends and beginnings of forms, changes of plane on the same form, or changes of colour or value. The selective defining of edges is one of the ways an artist can guide the viewer’s eye in a picture.

It is natural for a beginner to assume that all the edges in a realist drawing or painting should be sharp, because when we look at an object its edges appear in focus. However, edges that are on the periphery of our vision, or are moving, or are further away, are softer and can even be impossible to see at all. Careful variation of edges therefore is important to the illusion of realism and three-dimensionality, and also gives us some textural contrast. A painting with all hard edges will look rigid and full of cut-out shapes.

There is a scale of edges running from hardest to softest. Not everyone categorises them in exactly the same way, but essentially edges can be hard, soft or lost.

  • Hard edges are clear, crisp strokes placed side by side. They create contrast and therefore attract attention. Use your hardest edges to help draw the viewer’s eye to centres of interest. Some artists additionally talk of firm edges which are a bit less defined.
  • A soft edge is a slight blur between two forms. Objects only become sharp when we focus on them, so in general you should keep your edges soft. This is how the old masters painted. Soft edges let the eye roam unhindered.
  • A lost edge occurs when you can’t tell where one thing ends and the other begins. Perhaps the two forms are very fuzzy, or have very similar tonal values. Typically you might find it where dark hair disappears into a dark background. Lost edges are a good way to loosen up a picture. 



Here is an illustration of hard, soft and lost edges as used by Rembrandt:


Rembrandt: Portrait of Johannes Wtenbogaert (detail)

Of course much depends upon the context of the picture. If a hard-edged object sits against another of very similar colour and value, the edge will no longer jump out and may even become effectively ‘lost’.

Use your edges in combination with other aspects of a picture, such as contrasts of hue and value, to lead the viewer’s eye around the painting. They will help you create a sense of space, atmosphere and realism. We may lay out a few rules of thumb:

  • The brighter the light, the harder the edge; the dimmer the light, the softer the edge. 
  • The nearer the object, the harder the edge; the farther the object, the softer the edge.
  • Harder on hard, smooth forms; softer on soft, textured ones. 
  • Harder on motionless forms; softer on moving ones. 
  • Harder on the centre of interest, soft elsewhere.

You don’t need to define every edge fully, because the viewer will understand the forms and supply missing information from their imagination. This is most obvious with lost edges, but generally, you can establish part of an edge then let the rest dissolve away if you wish, because the viewer’s mind will assume the rest.

I think the beauty of soft edges comes from this shortage of information. A hard, clear form feels done and dusted, whereas the ambivalence within a soft edge allows the imagination to enter the work... to let the viewer supply what isn’t quite said.

Distance


Near objects are hard-edged and far objects soft-edged, so you can manipulate edges to communicate their relative distance from the viewer. The broad movement of edges into a painting with any depth of field, such as a landscape, will normally be from hard to soft. This doesn’t mean that everything near must be hard-edged and everything distant must be soft-edged. You just need to be aware of the tendency and to manage the way objects advance and recede so that they work together to produce the effects you want.

The example below illustrates a few principles at once. See how John Singer Sargent modulates the edge of Mrs Boit’s seat.


John Singer Sargent: Mrs. Edward Darley Boit (detail)

From a hard edge with strong contrast at the start (A) it continues into a soft edge with low contrast at (B). It almost becomes a lost edge at that point. Keeping the line as well-lit and crisp as it is at (A) would interfere with our understanding that it disappears behind the seated figure. I expect Sargent also didn’t want anything distracting us from Mrs Boit’s head and neck. The crisp line created at (A) points towards her face, a directional cue that would be spoilt if our eye was led downward again further along that edge.

The main point to take away is that, as the painter Stapleton Kearns puts it, edges need to be designed, not observed. And if your artistic intuition suggests handling an edge in a certain way, it may be best to go with it, even if it breaks one of the ‘rules’.

Making it ‘painterly’


Sargent’s brushstrokes cut a painterly dash
in his portrait of Gabriel Fauré.

Edges lead us into a related topic, namely how rough or smooth a finish you prefer. This is a matter of taste, but personally I prefer a ‘painterly’ texture. There is no mystery to this. It simply means we apply the paint in a more or less loose manner, allowing the brush strokes to show and create texture.

This is less of a challenge for traditional media than for digital painting. I don't necessarily advocate trying to make digital art imitate traditional media – the curmudgeon in me thinks if you really want an ‘oil paints effect’, use oil paints. But the pixel-precise control and mechanical tools available in software can make paintings look artificial and plasticky.

I think a painterly texture contributes to a sense of animation. A lively person moves around and is a bit blurry, whereas to closely peruse the details of a person’s face they have to hold still. Someone painted to a ‘perfect’ level of polish and focus can easily look frozen, whatever their facial expression.

Here are a couple of ideas:

  • Edges are very important. Let strokes of colour sit side by side with minimal blending and smoothing.
  • Be prepared to leave parts of the painting very rough and loosely finished. 
  • Avoid mechanical effects like computer-generated gradients or airbrushes.  
  • Don’t overwork the painting. 
  • Start with big loose strokes, then zoom in and create detail in key areas with smaller loose strokes. 

A couple of regular, versatile brushes are mostly all you need. Some artists prefer Corel Painter for its artsy brush tools, and custom brushes can make nice effects. There’s no harm in experimenting with your brush settings to make them more unpredictable or textured, and a customised Smudge tool (not the default smeary one) can give texture to your edges. Photoshop’s answer to reproducing paint effects is the Mixer Brush, which lets you blend colours on the brush with colours in the painting. 

But painterly texture is not primarily about what brush you use, so much as how you use it, and your understanding of light, colour and atmosphere. Only experimentation and experience will get you where you want to go, and don’t be discouraged if it takes a long time, even years, to figure it out. Do lots of studies aimed at solving specific challenges.

Skin texture


If you look at human skin closely, it is not smooth like porcelain but has a rough texture created by pores, moles and hair follicles. A bit of texture adds realism and helps you avoid the plastic look that overly ‘perfect’ digital skin can have. While most of your texture should come from using a painterly approach to painting the head, you can also add some separately as a final polish.

Digital artists sometimes use custom texture brushes for this. A simple method is to dab a few speckles of varying opacity onto a square, make it a bit blurry, then save it as a brush in Edit > Define Brush Preset. Apply some scattering, say 120%, and an angle jitter for variety.


Clever brushes can be seductive. Really all you need is a basic round brush, at small size, and use it to dab or scribble on a new layer so you can adjust the opacity etc to complement the skin. Keep it at a very low opacity.

In the before-and-after below I applied a custom texture brush to the right-hand image then scribbled on top for some extra effect. 



Many digital artists seem to get obsessed with fine detail. Unless you’re a hyper-realist, I don’t recommend you get carried away with trying to reproduce every hair and every pore, as I don’t believe it contributes to the feeling of the painting. A broad sense of texture will do perfectly well, and many superb paintings past and present don’t trouble with it at all. The great oil painters didn’t see any point in painting individual pores and hairs and you don’t need to either. The whole point of painting someone is to communicate something emotional, about their and/or the artist’s state of mind. To spend hours on relatively insignificant details is to misdirect your energies in my opinion.

A last word


Please bear one thing in mind. Techniques like the ones above can sound exciting to beginners, like ‘secrets’ that will help them paint like professionals. Theory is important, but artists shouldn’t let it stop them creating images the way they want to. For example don’t feel you have to rush off and remake your last portrait because it doesn’t include ‘colour zones of the face’. Even with broadly accepted ideas like colour temperature, artists disagree on where to draw the line between warm and cool (greens and purples can be contentious) or simply respond to them in different ways. The rule is not to follow a formula but to paint what you see – more or less. And if you don't like what you see, well, paint whatever you want!