Yes, the brain will adapt and do its best to give your vision a neutral white balance, however you're still looking through a filter (or not) which would have an impact on the relative brightness of different colors in the scene. Looking through yellowed lenses, blues will be darker and there will be less contrast within yellow objects. even though you may see a neutral color balance where grays are correct. For example, remove your yellow cataracts and you may notice the spots on aging skin more than you did before. Cheers, John C. -----Original Message----- From: Daniel Westcott Sent: Saturday, July 27, 2013 2:08 PM To: graxx@videotron.ca ; colorsync-users@lists.apple.com Subject: RE: Color Perception: How does coffee affect color perception? I assumed most on this list were aware of such things. As we age or corneas yellow. This naturally serves as a yellow filter and affects our ability to see light of that wavelength. Our brains have an adjustment mechanism for this and indeed for light anomalies in general and, so to speak, turns up the gain on the filtered light to still give us white balance. .. these are our knobs like what you would find on an old school analog drum scanner to adjust for an unbalanced transparency. ..it's one of the most exciting parts of color science to me. Writing this from my phone but I'll see about writing more on this later.