What is special about enlarger bulbs?

[Toffle]

I would have anticipated problems with using CFLs. Many of them do not start instantly, and also they have a warm-up time. Not to mention, the color spectrum is only an approximation of that given off by incandescents. What kind of CFL are you using, and do you use multigrade printing filters?

I've been wondering the same thing... especially the start up/warm up time. I can't imagine that you would have the same control over the printing process with these bulbs.

[Jon King]

I would have anticipated problems with using CFLs. Many of them do not start instantly, and also they have a warm-up time. Not to mention, the color spectrum is only an approximation of that given off by incandescents. What kind of CFL are you using, and do you use multigrade printing filters?

http://www.apug.org/forums/forum43/4...xperiment.html

That thread has some information. I did testing on a few other bulbs after I posted those plots. The effective color temperature does change the contrast of the "no filter" exposure. For me, a CFL would work well for split grade printing, but the intermediate filters would probably give results more contrasty than their grade would suggest.

I believe Ole uses/has used a CFL but has a shutter in the enlarger to control the exposure, and keeps the light on continuously to get around the warm up problem.

[fschifano]

I tried a CFL (daylight balanced) in an Omega B600 and in an old Bogen enlarger. It failed the suitability test immediately. Light output was very uneven with these two machines.The situation did not improve after than lamp had reached operating temperature. The image of the spirals was clearly visible on the baseboard. Color temperature be damned. If you can't get an even spread on the baseboard, it's already useless.

[Wade D]

The CFL I have is a couple of decades old since I last used it. It did require a warm up time and I just kept the red filter in place till the actual exposure. It worked well with Polycontrast filters. I just set up the darkroom again after 23 years so I'll have to see if it still works. The newer ones are instant on and smaller so I will have to test them. Maybe an LED light source like I',m planning for the 5x7 enlarger would work well in the 6x6cm also.