Quote Originally Posted by PeterB View Post
Hi Lee,
unfortunately we can deduce nothing at all from that graph. You state the reason why yourself "No attempt was made to correlate the vertical intensity/sensitivity scales" in fact to make matters worse, one scale is linear the other log and they are different units!

The best thing to do as you say is to test !!

I agree. I have previously posted on this confusion. The arithmetic scale of the LED graph completely hides from casual view the fact that photographic materials are sensitive at low light levels (thank heavens!) and if you draw that graph with a log vertical scale you will see heaps of overlap with the paper sensitivity.

Try looking at the LED by reflecting the light from the base of a CD at the angle that gives the "rainbow effect" to give some idea of the spread of colours. I tried it with some amber LEDs about which I had high hopes, and found not only yellow but aqua! Needless to say, they fogged until I placed a sheet of Rubylith over them.

Incidentally, those LEDs I had chosen because they had a narrower spread than most, according to their specs.