Hi,
with all the talk on digital, I feel like returning to the good old
darkroom. My eyes ache much more from the monitor than from the
acrid fumes :)
I am thinking about new way of inexpensive darkroom illumination.
LEDs. There are commercial solutions using LEDs, but they are about
50x the cost of the material used...
Here I want to share the idea, hear some criticism, opinions...
why LEDs?
- very narrow spectrum. Red leds - ~640nm, +/- 20nm !!! Nothing
below 600nm, nothing above 680nm! It's really a monochromatic
light. Ideal for VARIABLE CONTRAST papers, which have
sensitivity to about 530nm IIRC. Possibly, orange leds could be
used, which would be better for assesing the contrast of the B&W
print than red light.
- very low power consumption but high light output.
- cheap!!! 1 superbright led - 7000cd, 10 degrees illuminance,
costs under 30 eurocents. Around 12 of these would be just right
for small darkroom lamp. 12 of these would need 24V, also cheap
adapters' output.
cons:
very focused light. Not much diffused. Diffused colour leds are
available, but not in superbright variant. However, there are
superbright leds with 30-40 degrees cone of light, but harder to
find. Or a diffusor of some kind could be used, although this
would cut down the light. White leds are diffused enough
(because they use a second level of luminofors which emits the
white light), but unusable for darkroom, obviously.
Open for discussion, criticism, other ideas :)
Good light,
Frantisek Vlcek
