Additive and Subtractive Color Mixtures.
Most objects we see consist of more than one color. Their colors are mixtures of wavelengths of light. Two kinds of color mixtures: additive and subtractive. Additive color mixture refers to mixing the three primary lights: red, blue, and green. When all three colors of light are added, we see white light.Subtractive color mixtures are colors that result from mixing pigments, paint, or dye. Certain wavelengths are removed (i.e., subtractive) when colors are mixed in this way. Primary colors for subtractive mixtures are magenta, yellow, and cyan.
Without the distance cue of linear perspective, the bars now appear equal – which they are.