I did some research on bulb colour temperature the number that classifies the output colour of the bulb.
Ideally daylight has a colour temp of 5600 Kelvin.
I just found my bulb (Halogen) has a colour of 3400K, bang in the middle of bright yellow!! That one good bulb must have been a rogue. Was a good experience though
Colour temp chart:
http://www.mediacollege.com/lighting...mperature.html
My bulb specs:
http://www.donsbulbs.com/cgi-bin/r/b.pl/o-64663.html
There is my problem with the slight yellow tint!
3400K is classed as warm (under 3500K), 5600K is halfway between Intermediate (3500K+) and Cold (6500K+). A colder temp bulb than 3400K would work better.
I get the feeling I'll be cutting the bottom out of my OHP some time soon to fit a new bulb type!
The best bulbs for LCDs are around 5500K. An ideal bulb is this:
http://www.lamptech.co.uk/Spec%20She...m%20HTI400.htm
but its life is only 250hrs and they cost maybe 10x the price of mine.
I'll do some more research as its not easy to make the best choice.
I'm looking for:
a Metal Halide or hybrid of
250 to 400W
at least 25,000 Lumens
10-20,000 hrs life
52-56000K
preferably a small device with a dichroic reflector but I may go for fat 400W and no reflector
Something in between would work too but involves get a decent reflector for the type of bulb.
Back later