I am not color-blind, but there are shades of colors that, depending either on light source, what other colors are around, or just how I'm thinking about what I

I am not color-blind, but there are shades of colors that, depending either on light source, what other colors are around, or just how I'm thinking about what I'm looking at, will switch back and forth. I can pick out purple from violet, but I have had some clothing that will either appear purple or grey depending on how I am thinking about it (really). Similarly, I have a hoodie that is a timber green that at times appears brown, and a pair of corduroys that are brown that at times appear vaguely purple. I am nearly certain these shifting hue effects of the dyes were intended by the manufacturers.