This is a good technique: all you need to do is to have the principle color at 100% and add the second color at varying opacities. As you can see in the examples above, I’ve also smudged the paints a bit using the Smudge Delicate: that’s an additional method you can use, but it isn’t necessary.
Mixing Colors
I think it’s fair to say that most of us would say yes. However the reality is that a pure yellow mixed equally with a pure blue will make black or gray. So when we say that yellow and blue makes green we are not talking about pure colors. This may seem a bit pedantic, but if we start off with a false notion, then our attempts to mix color won’t be too successful.
One of the recurring complaints of painters (and not just beginners!) is that their colors lose their vibrancy and turn muddy; this happens a lot in watercolors where paints mix into each other, or when paint is applied in layers. The colors that are mixed effectively cancel each other out: so instead of making a beautiful green, the vibrant blue and yellow ends up as a muddy brown.
Other colors like green and red mixed together do the same thing.
But . if we mix yellow with a greenish blue, we get a brilliant green.
So what’s happening?
To understand why some paints will mix well and others not, we need to know a bit about color theory, which is the purpose of this article. But as it’s a bit technical, what I’ve done is to summarise the key points at the end of each section. If you prefer to skip all of the technical stuff then you can jump straight to A Correct Color Wheel
But before continuing it would be reasonable to ask if any of this is relevant to painting digitally? Well yes, it is, because when we paint in Photoshop it’s just the same as painting on paper. If we try to put one color over an opposing color (say red over green) then we will get mud, just like we do with paint and paper.
Pure Blue and pure Yellow, mixed in equal proportions, makes gray or black . and red and green also makes gray or black.
How we see the color of paint
RGB Primaries
If we look at a simplified spectrum of visible light, this is what we see: Red, Green and Blue.
Of course the spectrum is more complex as there is also orange and yellow between the red and green, and cyan between the green and yellow. But for the purposes of this discussion these three primaries are enough and we can think of white light as being made up of an equal mix of red, green and blue light.
When we apply paint, say red paint, to paper, what happens is that the paint absorbs the blue and green light and reflects the red light (which is why we see a red color, of course).
Imagine that a strip of red paint has been painted and red, green and blue light is shone onto the strip, with screens to stop the lights from overlapping. Well what we’ll see then is black where the red paint has absorbed the blue and green lights, and red where the red paint has reflected the red light.
And in this image, imagine that three strips of paint have been applied: red at the top, green in the middle and blue at the bottom; and again we shine red, green and blue light on these strips, as we did above.
Well the red strip will only reflect the red light, the green strip will only reflect the green light, and the blue strip will only reflect the blue light.
As it happens, we have three color receptors in our eyes: red, green and blue, so we can see these colors directly. Other colors require some processing in the brain: so when we see both red and green light at the same time, our eyes interpret this as yellow, which is a bit strange, but true; when we see green and blue at the same time, we interpret this as cyan; and, rather surprisingly, when we ‘see’ red and blue at the same time we interpret this as magenta (what makes this even more remarkable is that magenta is a color that doesn’t actually exist in the visible spectrum, it’s a construct of our brains).
So there are two things that are happening: on the paper some of the colors in the spectrum get absorbed by the paint and others get reflected by the paint; and in our eyes and brain the reflected light gets processed to give us the experience of red, green, yellow, orange etc. (In reality, all colors are constructs of our brain: outside of our minds there are only different electromagnetic frequencies and other animals see colors that we don’t, and don’t see colors that we do).
Now what happens when we mix red and green paint, say, apply it to the paper, and shine white light onto it?
Well, since the red paint will absorb the blue and green; and the green will absorb the red and blue . we are left with all the colors absorbed. So we end up with no light reflected, or black.
In this image I’ve separated out the red and green paints onto two strips with our usual red, green and blue spotlights. Blue will be absorbed by both the red and green paints so we see no blue reflected. Now, if you imagine that these strips are combined into one, with red/green paint applied, then the green will disappear because it will be absorbed by the red paint, and the red will disappear because it will be absorbed by the green paint.
I’ve shown this in the blob at the right where I’ve applied green paint over red paint (or vice-versa, it doesn’t matter) and you can see that the result is black. Of course, in practise with paint on paper, some light will always be reflected, so we will see some shade of gray rather than black.
For the same reasons, mixing blue and green paint or blue and red paint does the same: we end up with gray or black.
And, of course, if we mix all three colors, red, green and blue then we definitely end up with gray or black.
Mixing red, green and blue paint in any combination (or all three together) will give us gray or black.
The traditional artist’s color wheel
So you can see that red, green and blue paints by themselves are not much use to us! Which makes one wonder why artists almost always say that yellow, blue and red are the three primary colors and that with these we can get all the colors that we need, sort of at any rate. Is there something special about yellow?
Well not really. Yellow, red and blue do not make good primary colors: mixing red and blue will give gray, and yellow and blue will also give gray; so it comes as a bit of a relief to find that red and yellow will give an orange! Still, yellow, red, blue and orange isn’t a whole lot better than red, green and blue.
I can hear screams: ‘But I KNOW that I get purple if I mix red and blue!!’. Yes, red and blue will give a sort of purple, providing the paints are not fully saturated (in watercolors, providing the paints are dilute so that the paper white shows through).
I’ve taken a 50% diluted blue paint and put it on top of a 50% diluted red paint. What happens is that the blue paint absorbs only 50% of the red and green light and the red paint absorbs only 50% of the green and blue light: so all of the green is absorbed but 50% of the red and blue are reflected. Because the eye interprets red+blue to be magenta, this is what we see: an undersaturated magenta, or purple.
We won’t get good colors by mixing Red, Green and Blue paints; and we also won’t get good colors by mixing Red, Blue and Yellow paints. The traditional artist’s color wheel which uses Yellow, Red and Blue as the primary colors is confusing, at best.
EXPLORING COLOR COMBINATIONS
Many first-time homeowners or families who want to repaint their houses get overwhelmed by the task of selecting the right colors of paints, and often mistakenly think that choosing and combining different colors is a skill that is exclusive to professional interior designers. In this section, you will find tips on how to confidently explore color combinations for your home like a pro!
Using the Color Wheel
The first thing most of us learn about color is the color wheel. It may seem technical, but really, it’s just like a rainbow – it’s just one way of arranging colors. The color wheel gives us a unique and important insight into the relationships between colors.
Primary colors are the three most basic: blue, yellow, and red. Just like prime numbers in mathematics, these cannot be broken down into simpler colors, but can be combined to make all the other colors. You can find them in the color wheel as a triad, equidistant from each other.
Secondary colors lie in between primary colors, indicating that they are the combination of those colors. Between red and blue is violet; blue and yellow makes green; yellow plus red makes orange. Follow this principle and you get the tertiary colors that combine one primary and one secondary color. The more extensive the color wheel, the more degrees of combinations it can show.
Basic Properties of Color
In the real world, we rarely use pure colors together. There are certain properties of color that help us achieve harmony and balance as we combine different colors, in particular, for home interior design.
Hue
Hue is defined as pure color. When you say “green” or “blue”, what that usually means is what the color is, its most basic identity that differentiates it from the rest.
Tint
A tint of a color is the result of mixing an original, pure color with white. When you say you are “tinting” a color, it means you are adding white to it, making the tint lighter than the original color.
Shade
A shade of a color, on the other hand, is the result of mixing an original color with black. A shade of a color is darker than the original color.
Tone
Broadly speaking, any variation of an original color combined with a neutral is a tone. But here, we use a more specific definition: a tone is a result of mixing an original color with grey. Adding different strengths of grey (varying amounts of black and white) results in a change in a color’s tonal value. A tone is softer than the color you started with.
Additive color mixing, or let there be light!
White light contains the full spectrum of colors – red, orange, yellow, green, blue and violet. However, red, green and blue are considered the additive “primary” colors of the color spectrum. This is because, by varying the amount of red, green and blue light in a combination, all of the colors in the visible spectrum can be produced.
The key principle of additive color mixing is this: The eye adds together the different wavelengths of the light it receives, and it is this total light sensation that the mind interprets as a color. So for example, when red light and green light are combined, the brain perceives the resulting light as yellow. Additive colors always get lighter when mixed.
Subtractive color mixing, or what’s left?
Subtractive color mixing describes the process of producing colors by mixing light-absorbing substances. The key principle of subtractive color mixing is that it occurs outside the eye and brain. When we physically mix pigments, dyes or inks, we combine their light-absorbing behavior: Each absorbs (subtracts) light that would normally be reflected by the other. Thus, the only wavelengths of light that can be reflected by the mixture are those wavelengths that both substances reflected before they were mixed. Here are two examples:
- As we learned above in additive color mixing, a yellow paint reflects significant amounts of “green” and “red” light, stimulating the G and R cones in the eye, but not the B cones. A magenta paint reflects significant amounts of “blue” and “red” light, stimulating the B and R cones, but not the G cones. So, when a yellow and magenta paint are mixed, the yellow cancels out the “blue” reflectance in the magenta, and the magenta cancels out the “green” reflectance in the yellow. The common resulting reflectance is in the “red” part of the color spectrum.
- A red paint reflects light only from the “red” end of the spectrum, stimulating the R cones in the eye, but not the G or B cones. A blue paint reflects significant amounts of “blue” and “green” light, stimulating the G and B cones, but not the R cones. Because these two paints have no reflectance in common, mixing them results in black.
Optical color mixing, or the best of both color worlds
Optical color mixing combines features of both additive and subtractive color mixing. It’s achieved when small dots of pure complementary pigments are applied close together on a surface. From a distance, the eye will merge the colors to form new colors. By letting the eye do the mixing rather than using physically mixed colors, optical color mixing allows more light to reach the eye, resulting in greater vibrancy and luminosity.
- Handprint: additive & subtractive color mixing (http://www.handprint.com)
- Pantone: Color Think Tank (http://www.pantone.com)
