The dark side of the brick

Thanks to my mother and grandfather, I am colourblind. After discovering (c. 2001) that I knew all of the PhD students and postdocs in the colour vision team at Cambridge, I allowed them to experiment on me and was duly diagnosed as extreme deuteranomalous vision defective.  Putting aside the science, this means I have very limited ability to distinguish blue from purple, as well as struggling with red/brown and green/brown (oddly, I'm almost always fine with red/green).   Why am I writing about this in a Lego blog?  The answer should be obvious in that there are times when I really struggle to identify what colour my bricks are.  Particular challenges are: Dark red vs. reddish brown (this is my all-time worst and I struggle with them every time) Dark green vs. dark brown (especially cheese slopes) Transparent yellow vs transparent bright green (this is another random weakness which totally foxed Petroc when he tested me 20 years ago) Dark green vs. black (yes, ...