I held up a tablet from my breakfast plate and asked Marilyn what it was. "A new brand of vitamin," she replied. I commented that the drug firm should fire their marketing staff for putting a black vitamin pill on the market. She glanced at me, "It's not black, it's dark red."
The instruction on the handle of my weed eater says in yellow print, "Before removing weeds wound around the shaft, - - - - - the motor." Thinking that a strange instruction I looked more closely and with better light. The words "turn off" in dark red against the black background were nearly invisible. Small blinking red lights on equipment often escape my attention, so I burn out fuses on my radio transmitter tuner and fail to push the button on the gas pump.
It was in the first or second grade that I lost my purple crayon in the dark depths of
Currier RD. A Two-and-a-Half Color RainbowColor Blindness in Physicians. Arch Neurol. 1994;51(11):1090-1092. doi:10.1001/archneur.1994.00540230028008