Im not home at the moment and dont have my notes with me. That very same bathroom is under siege by the heating guys so have to move out temporarily. Anyways, if i remember right, I get around 8 to 10 mins exposures with New Cyano and more than twice that time (15mins) with traditional 1A + 1B. I use Lanaquarelle and FAW 300lbs. papers that i ALWAYS do presoaks in diluted household HCL. I print large mostly (whole 56 x 76 sheets) so they are enlarged negs but have used in camera 4 X 5 negs as references for calibration.
[QUOTE=if i remember right, I get around 8 to 10 mins exposures with New Cyano and more than twice that time (15mins) with traditional 1A + 1B. QUOTE]
Opps, sorry, this borrowed tounge is making me simple math-challenged...
i mean to say i get 15 minutes MINIMUM with trad cyanotype. Also, let me add that i hate math enough that id rather waste a lot of cut strips test printing than calibrating.... maybe thats what lured me into gum and gumovers in the first place.
Full sheets? That's pretty large indeed! I would like to see how they look like.
Your printing times are slow (about 1 - 1.5 stop) compared what I experience with 60cm BL bulbs (and "bone dry paper"), BTW...
Ok, so I've read some more and priced out some options, and here's what I'm thinking. I'm going to try the 2x CFL spirals and work light clamp reflectors, and make some tests to check exposure across the print. If it works up to 8x12 or 8x10, great. Even if it only works up to 4x6 or 5x7, that's still fine since it will let me make consistent small prints, and I do like my 6x6/6x7 MF contact prints. And if I need to expand it later, I can add more bulbs and some sockets, and build a grid of some sort, and I'm only out the cost of 2 reflectors (which are cheap).
1. I have a lot of respect for B&S, but in this case, their prices are a bit high. I bought a set of spiral BLBs from one of the wholesale lighting houses on the internet that have worked out fine for me. Actually, my local Home Despot is now carrying spiral BSBs.
2. I build my UV printer following the traditional 'pizza oven' design. I used six bulbs on six-inch centers. This may be overkill for the size prints I'm making, but I know that I don't have problems with uneven lighting.
3. I used plastic lamp bases (from Home Despot). By making the lamp array permanent, I eliminated the variable of setting up lamps each time that I print.
4. I use my setup for palladium/platinum printing.
5. I understand that black lights are commonly used for parties, but there's a difference between one bulb to make shirts glow, and a bank of lights that will produce a palladium print in 5-6 minutes. UV light can be dangerous - it is a known cause of cataracts. That's one of the primary reasons I opted for the 'pizza oven' design for my UV source.
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I'm guessing that you could get faster times with a higher wattage bulb, like these
As far as I know the BL CFLS just have a filter, their not specifically engineered for a higher production of UV light (yes, they do emit more as a percentage of total light, but I think the higher wattage bulb would work just fine.
Not quite correct, most fluorescent blubs will emit "some" UV but not enough for printing with (they will however fog your paper). The BL and BLB bulbs produce UV light in the range of 315-400 NM, which IS the range needed for printing alt process. 10-12 20W bulbs will be more than enough, and was mentioned - DO NOT look directly at these bulbs, the damage is not something you want to live with...plus a pair of glasses that block UV is not hard to find.
Originally Posted by totalamateur
How right you are-
I suppose I spoke before I looked into it; a closed mouth collects no feet.
Per the everpresent Wikifountain of KNowledge the BLB spectrum:
is quite clean when compared to a normal cool white bulb:
So I guess when I'm done using my growlights to grow stuff, I'll need to order Black lights for printing - Do these also work for salt prints?
Indeed, if we could buy the BL and BLB tubes with 100 watts it would be possible to construct a great printing light with just a few tubes.
Originally Posted by photomc
My setup is very similar to Louie's. I bought six 13-watt spiral BLBs at Canadian Tire (a low-end hardware big-box store) at about $7 a pop. Screwed them into plastic lamp bases, attached to a board in a 2x3 array. The whole thing is suspended at the top of a large Rubbermaid storage pail and fits IN the pail for storage.
Originally Posted by Monophoto
I don't do alt printing very often, so I can't comment on the longevity of the bulbs, but I can say that this option cost me about a third of what I would have had to pay to get a similar set-up going with "long" bulbs.
I generally do 6x9-inch Van Dyke prints and the exposure time is about 7-8 mins in my set-up.