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Comment on Why is #FFFFFF white, but mixing red green and blue paint is black?

Other comments are discussing additive vs subtractive colors, but that’s not accurate if you’re talking about mixing paints. Subtractive printing (CMYK) works by overprinting transparent inks, where each ink removes a different part of the spectrum. But mixed paints differ in two critical ways:

Paints are opaque, not transparent. Unlike subtractive inks, paint doesn’t invariably darken the color it’s painted over—instead it completely or partially replaces the underlying color.
Subtractive inks are applied to the substrate one at a time—they’re not pre-mixed and applied in one pass. If you mix paints before appying them, you get more of an averaging than subtraction or addition.

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SuperNovaStar@lemmy.blahaj.zone ⁨3⁩ ⁨days⁩ ago
A good way to get experience with the subtractive system would be to use watercolors, markers, or dip pens with ink, since those are transparent.

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Fondots@lemmy.world ⁨2⁩ ⁨days⁩ ago
You are right that paint is kind of its own thing and doesn’t really fit into the RGB or CMYK systems

But I would say it’s overall still subtractive. The paint and whatever you’re painting on isn’t giving off any light on its own, its just reflecting whatever ambient light there is (which is usually more or less white) and subtracting from that.

You could maybe argue that it’s more replacive (is that a word?) than additive or subtractive. It just kind of is what it is. It’s just replacing the substrate’s reflectivity with its own since it’s opaque like you said.

And when you mix paints it tends more towards that grey-brown because like you said it’s not layered, it’s more that each pigment is right there on the surface next to each other reflecting and absorbing their part of white light.

So if you mixed cyan and magenta paints together, instead of light passing through layers of cyan and magenta until all the red and green are filtered out so that only blue light reaches the white paper and is bounced back to your eye, you’d have cyan piments reflecting blue and green, mixed in right next to magenta pigments reflecting red and blue. So both are reflecting blue and the resulting color will probably look blue-ish, but the cyan is reflecting some green, and the magenta some red, so that pulls the color more towards grey (somewhere between white and black, it cant really get down to true black or true white because some light is always going to be absorbed and some reflected)

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- AbouBenAdhem@lemmy.world ⁨2⁩ ⁨days⁩ ago
  I’m not sure I’m accurately visualizing exactly what you’re describing, but I know from experience working with a two-color offset press that the results are quite different if you print two colors in two passes vs one pass (in which the inks are combined on a “blanket” where they effectively mix together before being transferred to the paper all at once).
  
  In the first case, the result is exactly what you’d expect from a subtractive color model; but in the latter case, the mixed ink that ends up on the paper is no darker than the component inks. The hue is similar whether overprinted or mixed, but the saturation is reduced in the mixed example.
  
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  - Fondots@lemmy.world ⁨2⁩ ⁨days⁩ ago
    Yeah that’s basically what I’m describing.
    
    I think you just have more of a precise, technical way of describing it probably because you’ve actually professionally worked with color and received some formal training
    
    Whereas I’m a guy with some self-taught Photoshop skills who paints minis, so my color theory is a little rough and ready.
    
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