I'm wondering what the signs are when a UV light bulb--for an Olite, possible quartz or metal halide (not fluorescent)--is getting old and near to burning out?

Does it happen all of a sudden like regular bulbs seem to do? Does the light start to fad, but otherwise is okay? Or is it possible the quality of the light starts to change, become inconsistent and affect the exposure of the plates?

I've been getting lots of spots and streaks in my plates that could be caused by a number of things and I'm trying to narrow down the possibilities.

Thanks, David.

David,
Does your unit have an integrator? If so, have you noticed if exposure times are getting much longer? I had to replace the bulb on my used nuarc when I first got it but I honestly can't remember the problem. I would call Olec and they should be able to help you much better than I can. I would suggest testing with a Stouffer but I don't know the recommended exposure for Imagon and this would only work if you have tested with a stouffer in the past.

Jennifer

Thanks Jennifer. I don't know if the light has an integrator or not. Its a homemade vacuum frame and you simply turn the light switch on for the needed time.

I'm not as concerned if the exposure times are changing, but as I said, some of my tests have "burned out" spots and streaks and I'm wondering if the light gets odd or inconsistent in any way--not just less. I'm trying my transparencies with different color inks (instead of the matte black which smudges), and I suspect that the ink is not consistently blocking the light, or is somehow letting the light "bounce around" causing the marks on my plate and print.

Best, David.

my uv light is not old but it 's something very delicate and i try to work with halogen lamp i find easily this sort of lamp everywhere i choosed a 1000 w and i obtained the same efficacity for the puretch film with the same exposure time :rolleyes:

Hervesachy, Please share detailed info for your exposure with the halogen. This is something I have wanted to test but just haven't gotten around to it being busy with some other things. Can you post a link or pic of the unit too?
Thanks,
Jennifer