Fastest UV print source?

[Harrigan]

I am doing some centennial pop prints and using my standard BLB bulbs for exposing the prints. I have 4 24" bulbs and am doing 5x7 prints right now. The exposure times are over an hour for the proper contrast negs, which are of course very dense. Or is it me that's dense?

Does anyone have any suggestions on how to shorten these exposures? Are BL bulbs going to give me any more speed? What about other light sources? I am looking for anything that will shorten these exposures. I would prefer to use an artificial source to stay fairly consistent with print times.

 

[rwyoung]

Unless I'm remembering it backwards, BL bulbs have more UV output in the right wavelengths than BLBs.

And there is always sunlight but tougher to get repeatable results if you want to make "editions".

 

[PaulH]

Harrigan,
I am in the same position as you. I have a box I built with 8 24" BLB bulbs in it. With Centennial POP my exposures range from 45 to 180 minutes. I am also trying to figure out whether I need to either re-build my unit or just get a timer that handles long times. There is a Gralab timer out there that will do up to 15 hours. Here is a link to their site:

http://www.gralab.com/products/details.asp?ID=7

What I do is just expose the prints while I am doing something else - like sleeping. I am using a Gralab timer that times up to 60 minutes. If the times are longer I just keep track and turn it on again when I think of it. I just accumulate the prints in an old film box and process when I have 6 to 8 prints.

 

[RobertP]

AmerGraph ULF-28 . I use a NuArc 26 1K and love it. With the light integrator you can really dial in exposure times. When it comes time to get a new unit I will go with the Amergraph ULF-28. Faster restrike time and it uses a new CWX lighting technology. Contact Sandy King, I think he was one of the beta testers for these units. At least I know he uses one anyway.

 

[sanking]

I am doing some centennial pop prints and using my standard BLB bulbs for exposing the prints. I have 4 24" bulbs and am doing 5x7 prints right now. The exposure times are over an hour for the proper contrast negs, which are of course very dense. Or is it me that's dense?

Does anyone have any suggestions on how to shorten these exposures? Are BL bulbs going to give me any more speed? What about other light sources? I am looking for anything that will shorten these exposures. I would prefer to use an artificial source to stay fairly consistent with print times.

BL tubes will not shorten print times by very much. I have tested the two types of tubes several times in the same light fixture and the gain in speed with BL is less than 1/4 stop, not worth the trouble and expense of changing the tubes if you already have BLBs. The tests included several processes, but not POP. However, POP is sensitive to the same radiation so I would expect similar results. BL and BLB tubes radiate about the same amount of light in the useful UV range. The difference between the two is that the BLB has a filter than cuts out all light in the visual range. But alternative processes are not very sensitive to visual light, so the net impact on printing is minimal.

Exposures of an hour or more indicate that your negatives are over-exposed. POP, and most other alternative processes, require negatives of high contrast, which you get with long development times, but they do not require dense negatives, which usually indicates over-exposure.


Sandy King

 

[Kerik]

Sandy's got it right. It's not your light source, it's your exposure. Your negs are way denser than they need to be. It's density RANGE that's important, not overall density. I use a UV box with 12 4-ft BL tubes and my POP times are generally under 10 minutes. Typical neg for me would be FP4 developed in Rollo Pyro.

 

[JBrunner]

My Nuarc 26-1k is one of the best things I have ever invested in. I would never go back to BL bulbs. If you can find a used one in good shape, at a good price, its a no-brainer. I got mine at a university surplus sale. There a quite allot of them around, because they were widely used industrially, have been obsoleted in may cases, and so are sometimes almost given away.

 

[Nicholas Lindan]

Nuarc 26-1K, puny little thing, no power ... Real photographers use:

http://www.nuarc.co.kr/images/630Helios_p.gif

Coming back to earth, platemakers often sell for less than the table-top printers. Usually the bigger the unit the less money it sells for. Old platemakers are often 'free if you will haul it away' . The small ones are the size of a small washing machine and usually need 220V. Power is 1kW for the table-tops, 2kW-4kW for small platemakers are 6kW for the large ones. The carbon-arc boxes work well and are just about always free.

'Overhead' units or printing lamps are other alternatives to consider. The nuArc OH1500 is an overhead HID printing unit with a small compact bulb and reflector for high definition imaging and is ideal for most alt-process work.

There are a dozen different makes - nuArc and Amerigraph are still in buisness and can supply service, bulbs and spare parts. Search for "plate maker" "platemaker" "plate burner" "plateburner" "exposure unit" "overhead exposure" "nuArc" "Douthitt" "Amerigraph" "Burgess" "Dianippon" "Olec" "Theimer" "Teaneck" "Sandmar" "Agfa" ...

Silk screen exposure units are the same except for the design of the vacuum blanket and frame.

 

[RobertP]

Keep in mind anything over 1500 watt will require a heavier 20 amp line to run it and it will not run off of a normal household current. I ran a separate 20 amp line dedicated for the 1000 watt 26 1K so as not to have any line draw from any other source. The 1000 watt works beautifully with short exposure times around 350-500 units and can contact print 20x24 with no problem. The vacuum table is a must as far as I'm concerned when you get into ULF negatives. Also the 26 1K has a very small foot print if darkroom space is an issue.

 

[Harrigan]

Thanks for the responses. I will try reducing my exposure next time but I didn't really over expose the neg on purpose, I simply gave it more processing time than I would have for a regular silver print. I exposed as I normally would for bw and increased my processing in an attempt to get the right highlight density for pop.

Well obviously you guys think the neg is way too dense so it must be the problem. As long as you're telling me I should be printing centennial pop in the 10 minute range with the BLB's I certainly need to adjust my exposure technique for this process.

 

[sanking]

Thanks for the responses. I will try reducing my exposure next time but I didn't really over expose the neg on purpose, I simply gave it more processing time than I would have for a regular silver print. I exposed as I normally would for bw and increased my processing in an attempt to get the right highlight density for pop.

Well obviously you guys think the neg is way too dense so it must be the problem. As long as you're telling me I should be printing centennial pop in the 10 minute range with the BLB's I certainly need to adjust my exposure technique for this process.

Is your film fresh? If not, it will have more B+F stain than fresh fine, and this can significantly increase exposure times with alternative processes. It will also increase exposure time with regular silver printing, but whereas with silver printing where exposures are usually in seconds, doubling or tripling the exposure is not a major problem. In alternative printing, where exposures are in minutes, doubling or tripling the exposure can quickly lead to really long times.

But don't worry. Every alternative printer has a few negatives that take on the order of hours to expose. Well, at least I have a few of those.

Sandy

 

[David A. Goldfarb]

Have you tried sunlight?

I find that my best negs for albumen require an exposure on the order of 45-60 minutes in indirect sunlight, but that becomes 15-20 minutes in direct midday sun. On an albumen printing day, I'll usually start around 10 a.m. and print until 3 or 4 p.m.

I've read that direct sun produces less contrasty results than indirect sun with albumen (contrary to expectations), but I haven't noticed such a great difference. One of these days I need to set up a good test for this.

 

[sanking]

Have you tried sunlight?

I find that my best negs for albumen require an exposure on the order of 45-60 minutes in indirect sunlight, but that becomes 15-20 minutes in direct midday sun. On an albumen printing day, I'll usually start around 10 a.m. and print until 3 or 4 p.m.

I've read that direct sun produces less contrasty results than indirect sun with albumen (contrary to expectations), but I haven't noticed such a great difference. One of these days I need to set up a good test for this.

Very good suggestion. I think printing with the sun is definitely the way to go with processes like albumen, salted paper and VDB. But you need a contact printing frame with a split back so that you can judge exposure.

Several years ago I spent a summer making salted paper prints printing with the sun, and it was very a very pleasant experience. Printing old processes with the sun really puts you in contact with the roots of photography. Plus, I found that the sun prints salted paper, and I bet albumen also, much faster than BL tubes.

I always printed with the frame facing the sun at right angle in order to maximize the point source nature of the sun. I found that I got better sharpness this way than printing in the shade.

Sandy King

 

[smieglitz]

For POP I'd also suggest the sun. It is fairly easy to gauge proper exposure as the prints begin to bronze when the proper exposure is reached (assuming the negative density range is OK).

Joe

 

[Harrigan]

Thanks again I will try the sun. I like the idea of getting into the roots of photography. The reason I used artificial was to maintain a more consistent light source. Do you suggest full sun or open shade?

I know my neg is dense but no way it's like 3 stops off or anything. I don't even know how that would be possible.

I have to admit I have used a new film here, Foma 200 and tray processed in in ABC pyro. This may be a bad combo but its what i have to work with right now. I have never used either of these before so I guess it's a little optimistic to use all these new materials and get the perfect neg the first time printing to centennial pop. Anyway the neg was printable at least albeit a days work to complete an edition of 5.

Thanks for helping.

 

[sanking]

Thanks again I will try the sun. I like the idea of getting into the roots of photography. The reason I used artificial was to maintain a more consistent light source. Do you suggest full sun or open shade?

I know my neg is dense but no way it's like 3 stops off or anything. I don't even know how that would be possible.

I have to admit I have used a new film here, Foma 200 and tray processed in in ABC pyro. This may be a bad combo but its what i have to work with right now. I have never used either of these before so I guess it's a little optimistic to use all these new materials and get the perfect neg the first time printing to centennial pop. Anyway the neg was printable at least albeit a days work to complete an edition of 5.

Thanks for helping.

I would suggest direct sun, with the glass of the frame aimed straight at the sun to maximize point source.

Printing in the shade does seem to give more contrast, but is much slower.

I have never used Foma 200 so can not comment about it. No reason ABC Pyro should not work, though.

Sandy King

 

[JLP]

Hope those of you using the Nuarc 26-1KS are not leading me down the wrong path? I'm going to pick one up in a few hours.
BL tubes works fine but my average exposure time is around 18 minutes for negative developed in Pyrocat MC and about 7-8 developed in Xtol.

What kind of exposure time are you getting from the 26-1K?
Thanks.

jan

 

[sanking]

Hope those of you using the Nuarc 26-1KS are not leading me down the wrong path? I'm going to pick one up in a few hours.
BL tubes works fine but my average exposure time is around 18 minutes for negative developed in Pyrocat MC and about 7-8 developed in Xtol.

What kind of exposure time are you getting from the 26-1K?
Thanks.

jan

I used a NuARc 26-1k along with a bank of BL tubes for a couple of years. The BL bank actually printed a bit faster than the NuArc, so don't expect to see a dramatic decrease in printing time with the 26-1ks. But it is a very good printer, and together with light integrator and vacuum frame should give great results.

Sandy

 

[RobertP]

It is just not the exposure times that make it nice. For one...it is a point light source with a vacuum frame a foot underneath it that allows you to dodge and burn much easier than a light box. It also has a light integrator and once you get use to using units instead of seconds you can get consistent results much easier. If it is only speed you are looking for you may want to reconsider. As the 1000 watter may not give you any significant increase in speed.

 

[JLP]

Thanks Sandy and Robert for the clarification. I got it in my garage now and need to find a place to put it so i can start using it.
Are there any notable change in sharpness between the tubes and the point light source?

Thanks again.

 

[sanking]

Thanks Sandy and Robert for the clarification. I got it in my garage now and need to find a place to put it so i can start using it.
Are there any notable change in sharpness between the tubes and the point light source?

Thanks again.

If you have been printing with a contact printing frame with your bank of BL tubes it is possible, maybe even probable, that you will see more sharpness with the NuArc. However, if you have been printing with a vacuum easel with the BL bank, results with the NuArc probably won't look any sharper.

Sandy

 

[epatsellis]

While we're on the subject of 26-1K's, anybody have a source for bulbs where the price that doesn't involve parts of the anatomy?


erie

 

[RobertP]

erie, Atlanta Light bulbs has replacement bulbs for 42.00

 

[JLP]

Sandy, Yes BL tubes and a contact frame.
It was actaully not so much the contact frame i thought would make a difference but the point light source. Thanks.

Thank you Robert for the heads up on light bulbs.


jan

 

[JLP]

Have now had a chance to print with the new to me Nuarc 26-1kS and i must say that it is worth every penny i paid for it.
A print (Pt/Pd) that took me 18 minutes to expose under my 8 BL tubes can now be exposed in 3 minutes and 50 seconds. Perhaps the Metal Halide is more efficient than the Mercury Vapor in the older K1 units? just a thought.
The Nuarc also seems to make a more distinkt difference with more or less Na2 in the coating. The vacum frame is pure joy to use.


jan