Before we proceed with colors, let me show you the blend modes I use most in Clip Studio Paint to help me with the shading and tinting (add shadows and lights) - different then the official/technical explanation, this is more a subjective/artistic view of how they work:
A - MULTIPLY for shaded areas works (almost) every time; the greyer the color, the less saturated is the shadow - if you want more saturated shadows consider adding some of the object’s local color to the painted hue.
B - OVERLAY works for shading but if the selected color is brighter than the local color, the result color will be lighter and more saturated. This is good to add reflected/bounced light and translucency (colored shadows).
C - ADD GLOW and Screen can be used to create atmospheric perspective; the effect of an object color being faded by the particles of “air”; the result color is lighter and less saturated.
D - COLOR DODGE or Glow Dodge is a good layer mode to “boost” the colors to a warmer temperature; it increases brightness, saturation and hue shift to yellow; prefer to use with low opacity layers or brushstrokes.
D - COLOR used with 100% black or white can be used to desaturate the image (remove its colors) while keeping the values. If used with colors or grays this layer helps to “unify” the palette to the selected color; works great to simulate an ambient color or gaze.
If you need a detailed explanation on how blend modes work in Clip Studio Paint, consider reading this article:
As I suggested before, please also read my article ‘Quick Rendering for Concept Art’ for a simpler breakdown of my painting process.
In general, the method uses this layer arrangement:
(a) the object is illuminated with direct light and / or global illumination;
(b) local colors are painted on a separate layer;
(c) light and color are combined; The light layer goes on top of the color using Multiply;
(d) colors need to be enhanced, so a copy of the color layer above all in Glow / Color Dodge mode gives good results;
Although similar, when we learn to paint digitally we also started by making light and shadow first.
However, unlike the above scheme, we use 'greys' throughout the image. This gray in the midtones ends up influencing the colors when we try to combine using blend modes.
See the examples below:
(A2) is what we usually do in the beginning; the image rendered with light and shadow using almost the full range of available grays (from light to dark);
We combine the colors (A1) with the light and shadow (A2) using Multiply and the result is that “muddy” look; boring and dark colors (A3);
The big problem here is the fact that the Multiply blend mode can't replace the dark tones of the image with color.
One solution for those who want to use this method (light and shadow first, colors later) is to use a Gradient Map to replace the grayscale with color tones (B2) - the result is more saturated colors in shadow areas (B3); which is especially good for painting skin.
An extra note is that you can also combine the trick from the previous method: a copy of the color layer over the entire image in Glow Dodge mode.
Use the mask to control the effect and the result (B4) will be much more enjoyable.
Knowing the limitation of the 'Grayscale to Color' method opened my mind to understand why colors always looked weird. No matter the combination of blend modes between layers, the result was always muddy.
However, I really recommend that you start practicing digital painting using this method (or whatever method you paint with values first).
Before I continue sharing new ideas about color, there is something very important that you need to know: color perception (Hues) is subordinate to value perception (Grayscale). Those are recognized differently by the brain.
In the image below, the first column shows the color wheel (A) changed in different ways:
(B) saturation reduced by 50%; (C) value reduced by 50%; (D) value increased by 50%.
In the second column we have the equivalent grayscale versions - note how some colors are actually brighter or darker than others, regardless of the adjustments.
Yellow, for example, is always lighter than blue. “Cold” colors are darker than warm colors.
This is one of the reasons why it is very important to keep an eye on the grayscale version of your image during the painting process. Sometimes a wrong color choice can make it difficult to paint a form turning in the space, or sometimes you may need to vary colors in an area without changing the form of the surface.
A very common technique for doing this real-time checking is to put a HUE, SATURATION AND VALUE adjustment layer on top and toggle it on and off when needed.
To add an adjustment layer in Clip Studio Paint: in the Layer panel click on NEW CORRECTION LAYER - HUE/SATURATION/LUMINOSITY - moving the SATURATION slider to the left the color is removed; moving to the right, color is increased.
But if you notice in the image below (A), this technique doesn't work very well.
The result is nothing like our perception of color because the software only removes the saturation value of the pixels on the screen. The colors will be grayed out evenly.
I will suggest two alternatives that work reasonably well: the first is to place a GRADIENT MAP layer using a BLACK AND WHITE map at the top (B) - it works, but visually I have the impression that the contrast between colors turns out a little high.
The second alternative is the simplest and most efficient: fill a layer with black or white color, set the layer mode to COLOR and put it on top. The result (C) looks correct and it is easy to turn this view on / off.
//Note: I made some tests and this scheme is identical to the well known method of Photoshop users (preview the image using the 20% dot gain color profile).
This knowledge (form turning occurs because of value rather than color) is a great tool as it frees us from making obvious choices when rendering a drawing.
Notice how in the first skull drawing I created the palette with similar colors. The design seems to have volume but the colors are very monotonous.
Using the technique to check values in real time I was able to "play" with color choices without losing the feeling of a 3D form.
In Clip Studio Paint you can enable the APPROXIMATE COLOR (Window -
Approximate Color) to help you choose different hues while maintaining a relative brightness between then.
Open the Approximate Color window and choose the HUE option for the rows and LUMINOSITY for the columns (A);
Now, choose any hue in the Color Wheel (B) and the Approximate Color window will show a gradation from light to dark of the selected color. Moving the Hue option to the left, you expand the options of hues available; doing the opposite reduces the gradient to a monochromatic scheme).
Now, let's discuss the idea of Local Colors - this is the “default” color of the object; the perceived color without light, shadow or reflection (A).
A good practice when dealing with local colors is, depending on the style of painting, to “spice up” the basic color with a few variations. The technique of checking values helps us again as we can make changes to the main colors without changing the feel of the shape.
In example (B) note how including blues, reds and greens gave a more natural and less cartoonish look to the gray of the helmet. In detail (C) see how these variations did not change (much) the perception of value.
The same can be seen in the head of the character. Slight color changes make the skin a little more “alive”.
While it’s a bit advanced to understand color picking with the RGB sliders, it can help you achieve this subtle hue shifts and color variations with a greater control.
Here’s my suggestion: enable the WINDOW - COLOR SLIDER and detach the HSV and RGB sliders so both are visible at the same time; now you will be able to adjust the colors “thinking in RGB” while you still have an easier method to control via HSV sliders.
In the example below I wanted to add blues to the gray of the sword. On the RGB sliders, I moved the B (Blue channel) to the right while I was checking and adjusting the S and V properties on top so the color value and saturation remains the same.
With the local colors applied to the surface of the object you’re know ready to create the illusion of form adding tints and shades.
In this step, be careful not to make a mistake that I made for a long time:
In example (A), note how to get the gradient from dark to light, I just changed the value of the color on each swatch.
It is not entirely wrong to paint this way, but if you represent all the materials and colors in your illustration using this formula, the end result will be a poor, vibration-free image - the painting will look like it is on a boring, cloudy day.
Example (B) shows an alternative: instead of just changing the value to make the color darker or lighter, try changing the color itself. Even a small modification will help make the image more vibrant.
Starting from the center color (red) I lightened the color by making it lighter and “warmer” (moving the slider toward yellow) - to darken the color I did the opposite, reducing the value and making it more “colder” (slider towards blue).
The recommendation that you change colors (Hue Shift) while lightening or darkening is valid, but in most cases you will not want to do it randomly.
So let me share a few ideas of what you can keep in mind while thinking about choosing colors for an illustration - especially if choosing colors to represent the effect of lights.
In the example below I would like to render this gray stone block in such a way that it looks integrated with the scene: scene (A) is an outdoor environment where the sky and the sun are the lights; scene (B) is an indoor environment where the only light source is the lit candle.
The first thing to do is to adjust the block's color exposure level - make the color value compatible with the lighting of the scene.
In (A), I have to consider that although it is darker than the lawn, the block will still be "lit" because it will receive a lot of reflected light. It would hardly have a very dark gray.
In the picture (B), I left the block with a dark gray because knowing that the only light would be that of the candle, this would not have enough strength to illuminate such a great distance.
//Note: Look for the “Law of the Inverse Square“ to get an idea about the size of the light vs. lightened area relationship
The next step is to paint the ambient light in the object.
In picture (A), I made all the upward-facing surfaces receive the blue of the sky, while the faces pointed to the side receive a bit of the green of the lawn.
In example (B), the color reflected on all faces were red (or orange) because even a dim candle light would tint all closer objects with its color.
//Note: The effects here are over-exaggerated just to illustrate the idea. A block of stone would hardly reflect colors so intensely - maybe if it’s wet.
Now I painted the direct light. In the image (A) I used a light yellow (sun) to color the upward facing faces of the block - the lawn will also receive this light so I brightened the green by increasing the value and pulling the color to yellow
Notice how In both cases, stone and grass, I used the idea of hue-shift to change the local colors of the surface. From cold gray to hot gray in stone and from green to yellow in grass.
In example (B) I used the same principle: all faces that point to the candlelight were given the yellow / orange color of the flame. The farther the angle, the weaker the light effect.
Did you notice that the images have already gained a "feel" of light just by changing the colors of the surfaces that receive the light?
Basically, all the shadows in the scene are the areas that we haven’t painted the light.
It's a little different way of thinking, especially if you're used to the grayscale scheme where shadows are painted in.
Otherwise, to continue this exercise let's paint some shadows as well - maybe a drop shadow coming from the tree foliage (A) or some creature that is between the candle and the stone block (B).
You can start by drawing the shadow by painting a totally black silhouette, making it follow the shape of the object where it is projected.
And here raises a common question when we reach this stage: “What color is the shadow?”
First, let's remember the fact that shadows are the absence of light.
If we paint the shadow completely black (as in the image above) it means that there is no other light in the scene - and that is not what is happening in the examples…
In image (A) the shaded part will eventually receive some of the light from the sky because this light source is huge.
In example (B) the candle flame, even weak, will color a little of the shaded area with a warmer color.
In both cases I made changes to the color of the silhouettes. Placing the layer in Multiply or Normal mode, with reduced opacity, helps keep details that have already been painted.
OK, with these new ideas in mind, let's move on to a final exercise.
Let's imagine that instead of a gray stone block our subject is now a ... little green dragon.
Before start thinking about color, let's go back a few steps and render the volumes using the idea of indirect illumination seen earlier.
The exposure has also been adjusted so that the dragon appears inserted into the environment.
I combined light and color using the previous scheme: light (multiply) over colors (normal) - that's enough to start painting.
As we already have a lot of things defined: volume and local colors; Let's start by adjusting the colors to the current lighting of the ambient.
In the image (A) the adjustment is a little easier - it just needs the blue of the sky being reflected on the dragon’s skin.
In picture (B) things get a little tricky because this particular combination (green and red) results in a curious property of color.
The combination of shades that are on opposite sides of the color wheel reduces our perception of color. The color neutralizes, creating greys.
Because our dragon is basically green in a reddish environment, the object will not be able to reflect its original color. The green would look more like a greenish-gray.
//PS.: I took some artistic freedom here, because the candle flame is not totally red (it is more like an orange.) The dragon would be really gray, or maybe almost black, if its color were more bluish. The color blue and the color orange are on opposite sides of the color wheel.
As in the previous example of the stone, the next step now is to paint the direct light that will complement the existing lighting.
In the picture (A), I had found the color of the light on the skin, increasing the tonal value of green, moving it a little to yellow and removing some of the saturation (intense sunlight usually takes the saturation out of the lighted areas).
In example (B), I did the same thing: I increased the value of green (or greenish gray) and reduced the saturation a little more to increase the neutralizing effect of opposite colors.
With those changes, the dragon feels illuminated and reasonably integrated into the scenes.
But we can go a little further by adding two light effects that help us better distinguish the difference between materials.
Let's start by talking about specular reflections:
Materials are distinguished and represented by the amount of light they absorb or reflect.
Metals, such as chrome, are highly reflective. Almost a mirror.
Wood, cloth and paper absorb more than reflect light. Hence it is easier to understand their local colors.
In the image below, I just painted the helmet with local colors (A) - by far it looks like metal. Maybe a stone helmet! Or maybe an incredible rusty metal.
In example (B), the helmet material looks like real metal because the surface is much more reflective.
To make the reflection, I just painted the suggestion of a scenery being reflected in the object.
Here's a really cool thing about metals (or reflective objects): the sharper/recognizable the reflection of the environment and the light source on the surface of the object, the more reflective it will look.
Compare the three images below and note how I was able to change the type of metal by only “blurring” the reflected image and also removing some of the saturation.
One quick method to distort a reflection painted on a surface is to use brushes with COLOR MIXING enabled. In the example below, notice how the default GOUACHE BLENDER acts like a blender because AMOUNT OF PAINT and DENSITY OF PAINT are set with low (some cases zero) values. If you have a favorite brush; duplicate it and play with these settings to create a blender that matches the brush’s texture.
Combining these two ideas: Diffused Lighting (light and shadow used to show the shape of the object) and Ambient Reflections (projecting “something” on the surface of the object) will help you create much more compelling materials.
In the image below, I rendered the helmet in two steps. In (A), I only thought about the reflections of the environment and the light; in (B), I just thought of the diffused light and occlusion shadow, overlaying the two images and using a mask to control what is seen from each layer I came up with a really nice simulation of a rusted metal helmet.
//Note: Those who work with 3D software already know this way of thinking when creating their materials. We can learn a lot by trying to apply some of these practices in the 2D workflow.
Just look over for PBR Materials to see how this rendering method works in the 3D pipeline.
Back to our little dragon...
I painted the reflection of the scene in the dragon as if it were made of chrome (A) - then I combined with the diffuse lighting render (B).
To achieve the effect of wet frog skin, I slightly blurred the reflected image and also tried to “break up” the reflection by putting more textures in my brushstrokes.
The result, although a little exaggerated, helped to better distinguish the materials in the scene.
One last intrusion before continuing with the dragon example…
Let's talk briefly about subsurface scattering.
This is that striking effect (at least for us artists) of light illuminating an object from inside.
Light, especially an intense light placed behind the object - will penetrate the surface of translucent materials and reflect the colors of its interior.
To paint this effect you increase the saturation and value of the illuminated part. The thinner the surface, the stronger the effect.
The important thing to remember is that the subsurface scattering effect does not happen only when light is behind the object. That would be just the ideal situation to visualize this phenomenon.
In general, any situation where bright light strikes the surface of a translucent object, you will notice brighter, slightly saturated colors in the shadow areas.
In the example below note how, on the left head, although properly lit, the orc skin does not look "alive" because the light is fully reflected (hence we can see its colors).
After some adjustments, the right head shows a bit more of subsurface scattering, especially in the shaded areas. The resultant material is something more likely to skin.
The perception of translucency is even greater on his teeth and lips.
In Clip Studio Paint, you have to play with your layer modes to simulate this effect. In the example below we have the surface (A) that reflects most of the yellow light; in (B) I made it translucent by replacing the shadowed areas with a bright yellow-green color.
To boost the effect even more, I painted a slightly yellow gradient right in the center of the ball; using the mask on this layer to paint veins and any internal “stuff”.
Finally we can go back to our little dragon and add this effect to some of its parts to finish the rendering.
In the example I increased the saturation on the thinner areas (wings, for example) and its body. I showed the effect of subsurface scattering by increasing saturation on the line separating shadow and light (terminator line).
The dragon is now set in the stage and we can now start finishing the illustration by painting more reflected lights and/or defining more of its materials.
Well, this exercise ends here - and for now that's it.
I hope I was able to show you some of the ideas that helped me understand this complicated subject.
There will always be more things to learn and explain, so don't consider this article a definitive treatise on the subject.
As I always suggest in my articles: Now Go Practice!
Thanks for reading.