Do's and Don'ts of Digital Painting
The possibilities of digital painting and digital art in general are almost infinite. There is basically nothing you cannot do as long as you just know how to approach it. Yet an abundance of programs and tools has both advantages and disadvantages. Knowing what to favour and what to avoid can be both a huge time saver and help you sidestep frustration.
What we will focus on in this article are some basic tools and techniques of digital painting; we'll try to root out pitfalls and see how to avoid them. Mind that all of the points mentioned below aren't rules carved in stone; there are always cases where breaking the rules can be much more fruitful for a certain effect than following them too strictly. With time and practice you will gain good judgment over when to follow the guidelines and when to leave them aside.
Note: Names of certain tools might vary depending on the art program you use.
While a clean white background can be just fine for a simple line sketch, it is not advisable to leave the canvas colour on default in cases where a certain mood needs to be set and for general works with background. Plain white will 'distort' your colours in a way that otherwise light colours seem too dark and washed out. Compare the impact of the interior colour on the left and on the right side in Img1.
Remedy: Instead think about the atmospheric aspect of the image you have planned and floodfill the background with the predominant colour or even better a manual gradient of several of the main colours.
Img1 - Colour perception depending on background colour.
Blending with the Smudge Tool
On first glance the smudge tool seems like such an easy and comfortable way to blend colours, particularly for beginners. Personally I believe however that this is the tool that needs to be avoided like nothing else when starting out with digital painting. On one hand blending colours with the smudge tool easily creates a very dirty and hard-on-the-eye effect and on the other hand it is thrice as time consuming as other blending methods.
The main problem with the smudge tool is the fact that it doesn't so much blend the colours as it just pulls them into each other in a mostly very irregular way that can take a long time to clean up. That also touches on the problem that the amount of colour shades you are using will stay at a minimum and thus make your painting appear bland and flat.
Remedy: The most effective, time saving and visually most satisfying way to blend colours is a combination of eyedropper tool and airbrushes. Colour A and Colour B can easily be blended by eyedropping A and applying it with a low opacity airbrush (soft or hard depending on the desired outcome) on the border between A and B, then eyedropping B and applying it on the same border. Keep eyedropping the colour blend you create and applying it to the border. Rinse repeat.
PS Hint: Holding down Alt while having the brush tool selected gives you quick access to the eyedropper tool.
Img2 - Comparison of airbrush and smudge tool blending.
Shading with Black and White
Choosing colours when shading should never be done by shifting them straight towards black or white. Natural lighting will always create a variety of hues even on a monochrome object and shadows are hardly ever clean black or grey. Ignoring that fact will result in unrealistic and flat looking objects.
Remedy: Use hue shifts of varying degrees to shade. For instance highlights on a red object could go over into yellow, shadows on a blue object into green,...
An easy rule of thumb would be to use the next warm colour in the colour diagram for highlights, the next cold one for shadows. Keep in mind though that depending on the prevalent lighting this could easily change. If in doubt don't hesitate to look at objects under different lighting in real life if available or make use of reference photos otherwise.
Img3 - Shading with and without hue shifts.
Shading with the Dodge/Burn Tool
The dodge and burn tools pose a problem not unlike shading exclusively with black and white. Even when making use of the different settings these two tools allow they still tend to mainly blacken and whiten, thus easily washing out vibrant and clean colours and creating the same flat effect as shading with black and white.
Remedy: Always favour shading with brushes. Airbrushes, basic round brushes, calligraphic brushes, texture brushes,...anything goes depending on the visual impact you are going for. The important thing to remember is that only brushes will give you full control over the colours you lay down while tools like dodge and burn create shades automatically which hardly ever look good.
Img4 - Comparison of brush shading and dodge/burn shading.
but keeping the above guidelines in mind can never hurt.