Night vision w/ color RA-4 paper?

Discussion in 'Color: Film, Paper, and Chemistry' started by DanielStone, Oct 16, 2009.

  1. DanielStone

    DanielStone Member

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    hey guys,

    I've got a nagging question, and so far, haven't been able to find a suitable answer to this question:

    Is it ok to use a low power night vision scope in the darkroom when making color contact sheets?

    I've been shooting quite a bit lately, and I don't like using printfile sheets to organize my negs(scratches from putting in/out), i just prefer to lay the negs down on the paper directly, just as I do with b&w.

    Now I've gotten ok in the dark(totally dark that is), but my main problem is the darkrooms(individual rooms) at school are so damn small, and I'm so damn big (6'5" 260#), its hard to get around without dropping a neg, or fudging something up in the process. bent a nice set of 3 120 negs the other day, thought it was totally under the glass, wasn't... :mad:)

    I'm using Fuji CA totally now (except for my roll of metallic 12"). either of these papers affected by faint IR light from a low-power scope?

    I've heard of film processing operations using these when observing dip n' dunk lines, or hand processing in large tanks in the dark. I'm also interested in this for this use as well (found a guy local selling some stainless tanks and 8x10/4x5 racks)

    Help would be appreciated.

    thanks

    Dan

    p.s. the reason why i'm so 'anal' about this is I'm kind of OCD about making clean and proper contact sheets. I'm sure some of you can see where I'm coming from.
    I'm also designing my own proofer (going to get the glass now actually :smile:)
     
  2. tiberiustibz

    tiberiustibz Member

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    I know that people do the same thing. Just make sure you're not emitting too much visible light. I've printed RA4 when I could literally see what I was doing using the light that filtered into the darkroom and I had no problems with fogging. I don't think you'll get any noticeable fogging. You can test it by putting the thing right up against a test strip for a minute and processing it. I think you'll be fine.
     
  3. mikez

    mikez Member

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    Daniel I feel your pain I'm 6'1'' 240 and I am always bumping into crap when I am doing my RA-4 prints and my contact sheets look like crooked death. haha the IR scope is a good idea, let me know how it goes, I may look into it.
     
  4. polyglot

    polyglot Member

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    A near-IR camera (about 1um) and some IR LEDs as a light source ought to work pretty well. I don't think (without having the data handy) RA-4 is sensitive much past 700nm.
     
  5. tiberiustibz

    tiberiustibz Member

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    I heard someone refer to using an "infrared monocle" or something to great success. I have a feeling once I start 16x20 and 20x24 prints it may get a little cramped though.
     
  6. PeteZ8

    PeteZ8 Member

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    Any reason you can't/don't use a color safelight?
     
  7. Greg Davis

    Greg Davis Member

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    I use a Thomas Duplex Safelight with the color filter set using RA-4 materials and can see across a 14 foot long darkroom without any problems. If you have the same kind of safelight in the darkroom, get a set of filters for it.
     
  8. DanielStone

    DanielStone Member

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    color safelight you say? I thought that you can't use RA-4 paper with a light of any kind? I've been gettin edge fog on my paper from the timer, and that's two feet away.

    I think I'll be looking more into the NV side of things.

    -Dan
     
  9. PeteZ8

    PeteZ8 Member

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    Also look for a Keiser/Osram (same company, same product) Duka 10 or Duka 50. These are (were?) top-o-the-line back in the day and cost huge cash. They can be had for around $50 or less now, but keep in mind the bulbs are very special and expensive, if you can find one. Fortunately they have a long bulb life but you may want to consider it a single use purchase just to be safe. You could probably buy 4 used ones for the cost of a new bulb.

    Anyway they also have an aperature control on them so you can dim them to match your conditions. Do a fog test, set the aperature, good to go!
     
  10. Alex Bishop-Thorpe

    Alex Bishop-Thorpe Member

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    We print RA-4 in a group darkroom - so of course it cant be pitch black, or we'd walk into eachother (well, more than we do anyway). We use very very dim yellow and green safelights, after a few minutes getting used to the very low light you can see what you're doing. As long as you dont keep you paper out for more than is necissary, you dont generally experience fogging. Keep your paper in a paper safe and just take it out when you need to expose it.
    We use an automated paper processor though, so I'm not sure how it would go if the processing was in trays.
     
  11. perkeleellinen

    perkeleellinen Member

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  12. hrst

    hrst Member

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    If you want a really cheap color safelight, just get some yellow leds. Not orange-yellow, not greenish-yellow, but just yellow. They can give you a very small illumination without fogging the paper. But LEDs have a bandwidth of about 50...60 nm and this limits the illumination level quite a bit. Better than nothing, though; I'm using this kind of safelight. It gives me 5 minutes to work with no fog. And, if you get Wratten 13 filter somewhere, you can always upgrade this LED system by adding the filter. Then you can at least double the illumination level. I'm looking for cheap wratten 13 filters but cannot find any... Anyway, where you can buy these filters?

    As far as I know, all color material can be used in IR safelights (except IR films). Again, LEDs are a cheap and easy way to make your safelight. Buy 940 nm LEDS; they are far away from red and should be 100% safe. I bought these: http://cgi.ebay.com/50-X-5mm-infrar...emQQptZLH_DefaultDomain_0?hash=item2c50552dba
    Not expensive, huh!
     
  13. mikez

    mikez Member

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    The problem is Daniel and I aren't working in community labs, we are in individual closet/rooms where it is too small for any kind of safelight... maybe the LEDs would work ok though?
     
  14. fiducio

    fiducio Member

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    My experience is that the tiny handheld safelights, hung in a basket in the tiny closet darkroom was just enough to get it set up. During print and delivery into the machine processor, I turned it off to avoid any fogging.
     
  15. tiberiustibz

    tiberiustibz Member

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    Color safelights only work because they're so dim that they don't cause any fogging. As a rule of thumb with those safelights, if it's bright enough to see what you're doing, you're fogging the paper. I got heavy cyan fogging last time I tried. The kodak publication even says "the safelight WILL EFFECT results." My theory is that white illumination is much less of all the wavelengths therefore fogging is spread across all three layers whereas our eyes perceive all of it. Probably completely wrong, but if it ain't broke don't fix it.

    My safelight filter cost $10 or so. Completely useless, but very cheap. I got mine at B&H.
     
  16. hrst

    hrst Member

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    I think that there is a big difference between persons in eye sensitivity. I cannot find any other reason to the fact that some people say that a color safelight is very good thing and some that it's completely useless. If you have a good night vision in your eyes, you will enjoy the color safelight without fogging the paper.

    It IS true that any safelight WILL effect results, but if it gives a fog level of, say, 0.05D, then this effect is not VISIBLE to a person who looks at the finished print.

    I have ran fogging tests and my safelight is okay for 5 minutes. I can barely see the paper in dark but it's not enough to help with contact prints. But, I have a button, when pressed, it gives much brighter safelight for a few seconds. I use it when it's time to move paper from DEV to STOP. It can also be used when arranging negs for contact print. It doesn't fog the paper if pressed only 3-4 times. In addition, I use a method of decreasing total safelight exposure by means of blinking the safelight at 0,5 Hz and a pulse width of about 30%; that reduces the total fog to 30%. If I added a very good filter passing only 580-600 nm to my LED safelight, I could probably at least double the illumination level without any visible fogging and get quite a good safelight. It's even more safe when the light source is yellow LEDs to begin with, compared to a light bulb.

    But if the safelight filter passes anything other than 580-600 nm, then it is probably completely useless, at least with an incandescent bulb. You have to be sure.

    I would recommend you to look at the paper datasheet, eg. http://www.kodak.com/global/en/professional/support/techPubs/e4042/E4042.pdf at page 5: spectral sensitivity curves. You can observe that there is a pit between 580-600 nm that is four stops less sensitive than red layer at 690 nm, and eight stops less sensitive than green layer at 550 nm. If you just had a broad yellow filter, you could have a safelight that really has to be very dim, but if your safelight really is only 580-600 nm, then it could be 16 times brighter. In addition, our eyes happen to be quite sensitive to about 580 nm, much more than to red light, for example.

    So, if you want to use leds and don't have a spectrometer or LED datasheet available, just take the color that is basically yellow but a very little orangish. Not orange, but even worse is to take greenish-yellow -- the reason can be seen easily from the spectral sensitivity curves of the paper.
     
    Last edited by a moderator: Oct 18, 2009
  17. ricksplace

    ricksplace Member

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    I use a Kodak #13 safelight filter. It doesn't appear to fog the paper. It takes my old eyes a few minutes to adjust, but I can see well enough to cut roll paper on a paper cutter, and see my way around the darkroom. I minimize the time the emulsion is exposed to the light. I cut the paper and place it emulsion side down until it goes into the paper safe. It's exposed to the safelight for about 10 sec. when I'm cutting it. When printing, the emulsion is exposed to the safelight only for the time it takes from the paper safe to the easle and from the easle to the tube, about 5-7 sec. The small glowing dots on my enlarger are more dangerous for fogging the paper than the safelight. Try to minimize the time the emulsion side is exposed to the safelight by using paper safes and tubes, and you'll probably be OK. I dont think I would use the safelight filter I have if I used trays, although it might be OK if you kept the paper emulsion side down in the trays, and use black trays to minimize safelight exposure.