> .. eye perceives photons in a logarithmic fashion adding two colors and halving them doesn't make an average. Are you using linear values or the usual funky

> .. eye perceives photons in a logarithmic fashion adding two colors and halving them doesn't make an average. Are you using linear values or the usual funky gamma space¹? With linear values, value 1 means x photons and value n means n·x photons. Always. You can resize, blur etc. and you get the expected results as if squinting, looking from a different distance etc. Works fine in RGB. However, with linear color you need to cover a lot of range for decent results, so instead of using linear 16+ bits per color channel, floats or ugly 8 bits, people unevenly squished them together, making a nice representative range of intensities in 5-6 or 8 bits, which we call "gamma space". Memory was very expensive and this way colors were nice. We have been using 8-bit colors (24bit RGB, 8bit grayscale) for so long that most people don't realize the difference between linear and "gamma" space values (I didn't for a long time). They say colors are weird and merrily average a couple of gamma values, because it kind-of gets the job done and no one's got time for this. It doesn't matter if your pictures get darker and off-color each time you resize them in your typical program. Working with colors properly would take more time and/or memory, so it's not really welcome everywhere and compatibility is a big issue. Even many artistic effects depend on these effects of gamma space "calculation". Instead, we add all sorts of workarounds, e.g. font darkening and lightening, because antialiased fonts are a fraction of a pixel thinner when dark, but thicker when white, when the AA "averaging" is in gamma space. ¹ Gamma space is a properly defined transformation, but you should really treat gamma-space values as palette color.