# "helmholtz" colour theme for mintty # # Copyright (C) 2022 Andy Koppe. # Licensed under the terms of the MIT License. # # The aim of this theme is to provide vibrant colours where the normal and bold # levels each have approximately equal brightness, with the exception of blue, # which is somewhat darker than the others to aid its legibility on light # backgrounds. Additionally, blue, red, magenta and grey have darker variants # for use as background colours to help legibility of light text on them. # # To level the colours, their luminance was calculated as follows: # - Gamma-expand the sRGB components by dividing each by 255 and applying the # sRGB transfer function (which approximately means applying exponent 2.2). # - Combine the components with formula Y = 0.2126 R + 0.7152 G + 0.0722 B. # - Gamma-compress with the reverse transfer function (approximately: apply # exponent 1/2.2). # # https://en.wikipedia.org/wiki/SRGB # # The colours were then adjusted to achieve equal luminance. However, that does # not actually yield colours with equal apparent brightness. This is due to the # "Helmholtz-Kohlrausch effect", which means that some saturated colours appear # brighter than others to the human eye. The theme is named after that. # # https://en.wikipedia.org/wiki/Helmholtz-Kohlrausch_effect # # There doesn't appear to be a generally valid model for compensating for the # effect, as it depends on observer, display device, and viewing environment. # Hence, correction factors were determined experimentally, ranging from 1.0 # for yellow to 1.45 for red, and the colour components adjusted accordingly. # Of course, that is a highly subjective process ... Black=0,0,0 Red=212,44,58;162,30,41 Green=28,168,0 Yellow=192,160,0 Blue=0,93,255;0,32,192 Magenta=177,72,198;134,54,150 Cyan=0,168,154 White=191,191,191 BoldBlack=96,96,96;72,72,72 BoldRed=255,118,118 BoldGreen=0,242,0 BoldYellow=242,242,0 BoldBlue=125,151,255 BoldMagenta=255,112,255 BoldCyan=0,240,240 BoldWhite=255,255,255