I'm only red-green colourblind.
My grandfather only saw in grey and he designed and built:
http://en.wikipedia.org/wiki/Williamson_amplifier
The man was a genius, I never did work out how he could tell which resistor was which. He must have had to ask every time.
Oh and if anyone is interested:
http://critiquewall.com/2007/12/10/blindness
That gives an answer to the most asked question when I tell people I'm colour blind.
"What colour do you see this/that as then?"
It's not quite right (I can make out some of the differences) but it's pretty close.