Bulb from enlarger reflecting off paper

[jbridges]

I print with a Durst CLS 501 enlarger and lately the circular shape of the bulb(Colamp 250s)(24v250w) is printing onto the paper. The bulb is like a projector bulb and it's the cone shape that is printing onto my paper. This happens if I am making a 6x6 or a 12x12.

I'm wondering if it's the last life surge of the bulb or something more serious. I haven't had it long enough to go through a lot of bulb replacements, but long enough to know that this is a new problem.

Any clues would be helpful. I do have a new bulb in my B&H shopping cart but wanted to hear from some pros before I buy something I can wait on.

thanks,

jb

 

[Nicholas Lindan]

You have the condensers in the wrong position, or the wrong condensers, for the focal length of the lens.

 

[Ian Grant]

If there's condensers then it's the wrong light source, this is a diffusion head, with a light mixing box.

Sometimes the silver reflector material on the cone deteriorates, I've had it happen with similar bulbs used for display purposes.

Ian

 

[jbridges]

I'll check the cone for deterioration and go ahead and order a new bulb, can't hurt. Thanks for the information!

jb

 

[ic-racer]

Hmmm...very odd. Did one of your diffuse plates fall out when changing mixing boxes or something?

 

[jbridges]

That's a good idea. I'll check tonight.