Given a mix of color (be it a tint or shade), how can you correctly match the corresponding complementary color?

For example, I had a shade of blue for which the complement is orange. But I found that mixing the orange a little bit and I ended up with that “shimmering” effect that I was seeking. But, I don’t know how I came up with it! LOL

It occurs to me there must be a method to get there that doesn’t involve trial and error

Could someone provide a pointer or two?

Thanks.

Forrie, you can rely on a very small set of CMYK colors to apply color wheel theory to them. However, the color wheel theory is flawed when you expand it to a bigger array of pigments.

An example is Phthalo Green Blue Shade (PG 7) and Dioxazine Purple (PV 23, blue shade). Color wheel theory dictates that a mix of green + purple is always a color close to neutral, but mix this exact pair and you’ll get a very dark blue – close to Indigo (PB 66) – instead. There are many other examples: Green Gold (PY 129) + Quinacridone Magenta (PR 122) will give you a warm yellow instead of green, and Cobalt Teal Blue (PG 50) + Lemon Yellow (PY 3) will give you a saturated, light green, instead of just a light, desaturated grayish green.

Again, unless you rely on very narrow a set of colors, there is no way to predict exactly what their complement is.I suggest you do a color mixing chart with your pigments and keep it always handy, so you can consult it when you need. Not only is this approach a time-saver, but it also helps you to improve on color mixing!

Well, a great deal depends upon your specific goal for using a complementary color.

For example, if you goal is to darken a color, that often requires a different approach than if you are trying to gray a color.

In either case, though, the use of a neutral Black is quite effective.

Face the simple fact that if your were to mix enough Black, Or neutral gray with a color, you would inevitably reach a point at which it would begin to turn your color neutral, by the sheer volume of Black (or gray).

Using a neutral Black or Gray to neutralize a color (gray a color) is quite effective method to gray a color–or to darken it. Black darkens a color much better than using a complementray color because a complementary color eventually turns the original color neutral–sometimes before you have reached the level of darkness you would have preferred.

Black effectively darkens secondary colors (Red, Green, Blue), without changing their hues, and it will do so (without changing their hues, until so much Black has been added that if finally becomes “Black”. However, Black will shift the hues of primary colors if mixed with them. Both these characteristics can be profoundly useful, but they first need to be acknowledged as truly existing.:D

Bill, excellent advice, as always! I’d also like to add that any black with a bluish cast will shift yellow primaries towards green. To successfully darken yellows in CMYK without shifting their hues to green, just add a small touch of magenta (or a good red, if you have one) to them.

This is precisely why I reintroduced black into my palette. The whole business of mixing complements to darken colors is more tedious and expensive than it needs to be. Also, it guarantees that you’ll never mix so much of the complement that it shifts toward the complement.

I like to think of black as a “home base” color.

I really like Raw Umber (PBr 7) for that. But it has to have a yellow shade to it (or a slight greenish cast, at best). A good Raw Umber than darken even yellows softly, without much adjustment.

This isn’t about darkening colours.

I’m afraid that it would have to be trial and error if you wanted a true complementary.
You would need some way to test that your colour and its complementary mixed to a neutral grey, like neutral grey swatches or a
spectrophotometer.
Even if you found a perfect complementary for your colour, it would be unlikely that it would be the complementary for a lighter tint of your colour.

Just on the ‘shimmering’ thing:
I have done multiple tests on people that believed that colours mixed with complementaries were somehow more vibrant than those mixed using black.
They mixed a colour and I secretly I mixed several colours that were very similar, using two adjacent colours on the colour wheel, plus black and white. For example, orange, yellow, black and white.
I placed those colours around the original colour and asked the subjects to point out the colour they mixed.
Not one of them has been able to, (and they had something like a one in five chance of guessing the right one).

Really excellent point! A color is a color, and it doesn’t make any difference how it got to be that way–at least as far as the viewer is concerned.

This is precisely why I reintroduced black into my palette. The whole business of mixing complements to darken colors is more tedious and expensive than it needs to be. Also, it guarantees that you’ll never mix so much of the complement that it shifts toward the complement.

I like to think of black as a “home base” color.

Good thinking here, in my opinion. And, if you discover your tubed Black to have too much of a decided color bias to it, just add a bit of color that is the complement to that, to bring it closer to true neutral. Use some sort of commercially available Gray Scale to which to compare your paint mixture. When I want a neutral, I often mix a bit of Raw Umber with my Lamp Black. Once I get the “neutral” (or near neutral) that I want, I then mix that with any color I wish to darken, or gray.

Bill, excellent advice, as always! I’d also like to add that any black with a bluish cast will shift yellow primaries towards green.

Thank you!:) But, you don’t even need to use a Black paint that has a blue cast in order to create Green with a primary Yellow. Select some Black that you consider to be a “warm” black, and it will also create Green with Primary Yellow. The reason is more because of the Green reflectance of Yellow (Yellow represents equal reflectance of both Red and Green light) coming to the forefront, whenever Yellow is darkened with a “darkening agent”. Even Raw, or Burnt Umber will exhibit this effect to some, small extent.

The interesting fact is that the addition of Black (neutral) will also affect the other primary colors, Cyan, and Magenta, shifting their hues–the greatest to exhibit the effect being Magenta, which will begin to exhibit its “Blue-ish-ness” with the addition of Black. It becomes a beautiful, contolable lavender, and I’ve used that effect in many flower paintings.

To find the additive complementary you might think that you could just refer to the hue circle of a graphics program like Photoshop and find the hue 180 degrees away, but unfortunately this only works accurately on the yellow-blue, magenta-green and red-cyan axes, not in between. I’ve posted a reference circle showing true additive complementaries at the bottom of this page:
http://www.huevaluechroma.com/043.php

By the way, the contrast of additive complementaries is often very harsh and it’s by no means a universal belief that they create a pleasing harmony.

colour harmony theory is based on ‘[I]mixing[/I]‘ complementaries.

There are no any color harmony theory. Harmony is not a physics. I guess, it is more of a human biology, rather than optic or even mathematics. You can match some color harmony using complementaries, but you can also match color harmony using just another methods.