Black Light bank for alt processes

fhovie said:

I read a lot of fine articals - Thanks all. I am considering using a bank of Black Light bulbs and I have the following questions:

Do they have to be florecent? - there are a lot of 75W black light incandecent bulbs available cheap?

Normally the BL and BLB bulbs (flourescent bulbs) are used. I would imagine that the 75 W black light bulbs would emit UV. The problem that needs to be addressed in their usage is of gaining even illumination.

If they have to be florescent, will 4 of the 18" 15w bulbs work or do I need to get larger more powerful bulbs?

Those that I have heard address this indicate that bulbs are placed very near each other (like immediately adjacent). I don't know what size contacts that you are planning on using. If 4X5 then I would think that four bulbs should be adequate. I would place them as near to the printing frame as possible and still allow room for burning and dodging

Will this bank be necessary for AZO? I have some on the way and have never used it.

Actually the UV source will probably be to intense for use with Azo and still allow time for burning and dodging. Unless they are some distance to away from the printing frame. While Azo is very sensitive to UV those of us that use it primarily use the reflector flood lamps. (150-300 watt) mounted about three feet above the printing frame. These reflector floods emit blue spectrum light and that will expose Azo.

I will use it for the following processes - Cyanotype, Kalitype, Van Dyke Brown and Aubumum

I found many lighting systems that would be fine according to the articals I read that cost $300 to build because of the very expensive ballasts used. I also know that the sun shines everyday for free here in the desert north of Los Angeles and that the first 80% of benefit comes from the first 20% of cost. I have tried work lights and even lights that were for plants (High in UV?) and all they did was cook my frame. So I know that not just anything will work but I am not spending a zillion bucks on precious metals and I am not spending $300 for lights for this now. ... Will photo flash work? I have 2000 watt sec of flash here ...

Photo flash is typically pulsed Xenon and it should have a fair amount of UV emission (depending on whether the tube is coated). If you plan on using it, then I would wonder about controlling the exposure and additionally I would plan on setting my light up in a "bank" to create a large enough "source".

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fhovie said:

I read a lot of fine articals -" Thanks all. I am considering using a bank of Black Light bulbs and I have the following questions: Do they have to be florecent? - there are a lot of 75W black light incandecent bulbs available cheap?"

Frank,

I don't know if the BL incandescent bulbs put out enough UV light. But if they are really inexpensive I would buy one and stick it in a 10" reflector and try to expose a 5X7 or 8X10 cyanotype at a distance of about 15" from the light to the printing frame. If you get enough density with an exposure of less than 20 minutes it would probably be feasible to gang up 4-6 of these lights to get enough illumination for prints up to 11X14 or 16X20 size.

One inexpensive light that does put out a lot of UV radiation is the common 175 watt mercury vapor lamp available in night lights. If you use this unit at about 10" from the printing frame you will get reasonably short exposures and be able to print up to about 8X10" size without excessive light fall-off at the edges. You will need to tape off the senor on the top of the light. Just hang it the ceiling or bolt it to the wall and you are in business. Leave it on for the duration of the printing session because the light takes about 5-7 minutes to reach maximum output. At a cost about $40, including ballast, reflector and bulb this is about the least expensive UV source available.

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