How Can We Accurately Model Paint Color Mixing Using an Algorithm?

Algorithm for Mixing Colors in a Paint Colorspace

When mixing physical paints, the resulting color differs from what one might expect when mixing colors on a digital screen. This is because paint mixes by absorption, whereas digital color mixing involves emission.

Paint Absorption and Digital Color Mixing

• Paint Absorption: Paint absorbs specific wavelengths of light, resulting in the visible color. For example, blue paint absorbs red and green wavelengths, reflecting only blue light.
• Digital Color Mixing: Digital displays emit light to create colors. When mixing two digital colors, the resulting color is a combination of the emitted wavelengths.

Algorithm for Color Mixing in Paint Colorspace

Mixing colors in a paint colorspace involves subtracting the absorbed wavelengths from white light (255, 255, 255). For example, mixing blue paint (absorbing red and green) with yellow paint (absorbing blue) would result in a muddy green.

Alternate Solution Using HLS Colorspace

Alternatively, using the HLS (Hue, Lightness, Saturation) colorspace can provide more intuitive color mixing results that are independent of the physical absorption properties of paint.

Python Code for Color Mixing in HLS Colorspace

Below is a Python function that calculates the average between two colors in the HLS colorspace:

import math
from colorsys import rgb_to_hls, hls_to_rgb

def average_colors(rgb1, rgb2):
    h1, l1, s1 = rgb_to_hls(rgb1[0]/255., rgb1[1]/255., rgb1[2]/255.)
    h2, l2, s2 = rgb_to_hls(rgb2[0]/255., rgb2[1]/255., rgb2[2]/255.)
    s = 0.5 * (s1 + s2)
    l = 0.5 * (l1 + l2)
    x = cos(2*pi*h1) + cos(2*pi*h2)
    y = sin(2*pi*h1) + sin(2*pi*h2)
    if x != 0.0 or y != 0.0:
        h = atan2(y, x) / (2*pi)
    else:
        h = 0.0
        s = 0.0
    r, g, b = hls_to_rgb(h, l, s)
    return (int(r*255.), int(g*255.), int(b*255.))

Using this function, we can approximate the result of mixing blue and yellow paint, for example:

>>> average_colors((255, 255, 0), (0, 0, 255))
(0, 255, 111)

This approach provides a more intuitive color mixing result that is not constrained by the absorption properties of physical paints.

The above is the detailed content of How Can We Accurately Model Paint Color Mixing Using an Algorithm?. For more information, please follow other related articles on the PHP Chinese website!