van Gogh chose paints for their immediacy of color, sometimes without understanding the problems of hue shifting and degradation displayed by certain pigments. This causes a huge headache for curators and in many cases the changes are irreversible. For example his chrome yellows contain sulphides which have significantly darkened and browned through exposure to UV. He also used various red lakes that are prone to fading and discoloration.
van Gogh famously wrote in a letter to his brother Theo: "Paintings fade like flowers... All the colors that impressionism has brought into fashion are unstable, so there is all the more reason to simply use them too brightly - time will tone them down only too much".
Any theory of color vision deficiency that attempts to reconstruct the color balances that van Gogh actually saw should take into account the hue/value/chroma of his paints such as they possessed when originally applied, and also consider that van Gogh intentionally adjusted his aesthetic to render color schemes in expectation of future pigment degradation, and that these adjustments cannot have been an exact science.
van Gogh famously wrote in a letter to his brother Theo: "Paintings fade like flowers... All the colors that impressionism has brought into fashion are unstable, so there is all the more reason to simply use them too brightly - time will tone them down only too much".
Any theory of color vision deficiency that attempts to reconstruct the color balances that van Gogh actually saw should take into account the hue/value/chroma of his paints such as they possessed when originally applied, and also consider that van Gogh intentionally adjusted his aesthetic to render color schemes in expectation of future pigment degradation, and that these adjustments cannot have been an exact science.