Problems finding flash point

Discussion in 'Enlarging' started by naugastyle, Nov 9, 2009.

  1. naugastyle

    naugastyle Member

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    I'm finally trying to do a safelight test after multiple printing sessions, and couldn't even get the flash point of my paper. I used Ilford Warmtone and Cooltone as I've already been using these and had good results. f/16, timer at 1 second, 6 steps, pulled sheets out of the middle of pack.

    The Cooltone resulted in a mass of dark grey. (Actually, the first time I tried w/ steps of 2 seconds and it was all black). The Warmtone showed 6 distinct steps at least, but all fairly dark...the lightest was definitely medium grey. I don't understand how this is possible when I usually print at f/11 without issue.

    This isn't my personal darkroom, it's been a rental space available for I believe nearly two decades and is rented by perhaps a dozen people at a time (individual use, though). It doesn't sound like anyone's ever had issues with the safelights, which is why I didn't check when I first started. I've only printed 5 sessions, fairly certain I'm using unexposed paper for the test, but is it possible that these two papers would be fogged THAT badly that they are medium grey with only 1 second exposure @ f/16?

    I didn't continue with the actual safelight test, by the way...the greyness was really throwing me.

    I should also mention there is no red safelight (other than the red filter for the enlarger). There is a yellow safelight about 5 ft from the enlarger and an amber light about 12 ft from enlarger (perhaps 6ish ft from my developing tray). It's already a fairly dim room, but there is a third option light I can switch to (also amber), very dim, that would put me in near-total darkness.
     
  2. jeffreyg

    jeffreyg Subscriber

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    Since it's not you equipment maybe the lens diaphragm is faulty and not actually closing down?
     
  3. MattKing

    MattKing Subscriber

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    Try doing one print where the entire process is in total darkness, to see if you have another source of fog. It could be something silly, like someone replacing print developer with something much more active.

    If the result of the total darkness print is okay, do another one, but after enlarger exposure do a graduated safelight exposure to test the safelights.

    You may also want to try turning off the yellow safelight - that sounds like a source of problems to me.

    Matt
     
  4. naugastyle

    naugastyle Member

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    Jeffrey, I don't think the diaphragm is faulty, as it's pretty dim at f/16 and very bright (enough to wreck my night vision for a bit) at f/2.8.

    Matt, you mean a regular print w/ negative, not just exposing the paper, right? I can try that next weekend. There is no "someone" to replace my developer though, every renter brings their own chems and clears out completely at the end of a session. This time it was definitely not very active, it was Dektol diluted 1+3 saved from my last printing session. After I gave up on the test I continued to use this developer for the rest of the session and it was fine.

    Just to be clear, you mean I should print something out normally in darkness, then use the same exposure time for the second print but leave it out in the safelights for a few minutes to see if it looks different than the first print?
     
  5. MattKing

    MattKing Subscriber

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    Nancy:

    You have it exactly right!

    Good luck with the test!

    You can expand the utility of the safelight test if you graduate the exposure - try something like putting 4 small opaque items on the exposed print, and remove one item each 90 seconds.

    Matt
     
  6. naugastyle

    naugastyle Member

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    Thanks so much for your help :smile:.
     
  7. edtbjon

    edtbjon Member

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    One thing which most (not all) descriptions about safelight testing seems to leave out is that you should pre-flash the paper strips, so that they give a light grey value to start with.
    The reason for this is first, that a pre-flashed paper is more like a print, in that it have received some exposure.
    Second, whenever a paper have received some exposure it is more sensitive to further exposure. This holds true regardless of the first exposure being intense enough to gray the paper or not. In the old days of graded paper, you could easily make a grade 4 paper into a grade 3 or even 2 paper by intentionally pre-flashing it. Apart from changing the grade of the paper this also made the paper faster (more sensitive to the second exposure).

    Without knowing what kind of paper(s) you're working with, if you test your safelight propery and adjust accordingly, you may find that suddenly you can find both grade 4 and 5 in that pack of VC paper. :smile: It is a bit of revealing hard work, but it's worth it in the end.

    //Björn
     
  8. Greg Davis

    Greg Davis Member

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    This safelight test from Kodak is easy to do. It divides the paper in half, both sides exposed to the safelight, but one half given enlarger exposure before the safelight, the other half after.
     
  9. Nige

    Nige Subscriber

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    regarding finding the flashing time, you need to 'do something' to give it less light. My 'regular' exposure for an 8x10 print would be 8-12secs @ f8. When I flash paper with that enlarger (I actually use 2 enlargers and flash paper with the one I'm not using) my flash time is about 2secs @ f22 with the enlarger head moved to the very top of the column. Stopping down and increasing the distance will lower the light output and hopefully get you to a point where you can conduct a flashing test with meaningful results. You might even need to add some filtration. Another thing I like to do when doing one of these (remember you need to do it for each paper you use) is to cover up part of the test sheet along the direction you run the graduations. You end up with your graduations getting darker and a section of paper white beside each one which I find allows me to decide which graduation 'just' shows some tone.

    Cheers, Nige
     
  10. ic-racer

    ic-racer Member

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    Your 'usual printing f/11' exposure is likely a 'minimum exposure for maximum black' if you get good looking prints.

    The flash exposure will be way, way, way, below that. Just use less time (less than one second) or raise the enlarge head up more. Its not unnusual to need a very short exposure and small aperture to flash.
     
  11. edtbjon

    edtbjon Member

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    If you add filtration to act like a grey filter I can follow you, but are you intending anything else with it?

    //Björn
     
  12. Nige

    Nige Subscriber

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    No, I was just meaning to lower light levels (i.e. add time), either via a 'proper' ND filter or Contrast filters. I only flash with 'white' light.

    I have heard someone claim flashing with low or high contrast filters can give different effects, but I've never tried that. When flashing paper, you're usually trying to get the paper to take highlights that normally won't print, so maybe a low contrast filter would work better... or is it a high one? Hmmm, I have no idea! Would need to try it.
     
  13. naugastyle

    naugastyle Member

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    Thanks for all the advice. I tried again with different papers this weekend, but since I can't go below 1 second (at least, not accurately) on an analog timer and 1 second is pretty dark anyway, I still couldn't find the flash point. I used MattKing's option of exposing a negative normally in the dark, then placing coins on it before turning on the safelights. I'm not the most patient person so I only tested two papers this week, as all I could think about was the prints I could have been making instead :smile:.

    My normal setup is a yellow light about 6 feet from the enlarger, 5 feet from safebox/paper cutter, 4 feet from developing tray, and an OC light nearly 6 feet away from tray. In case anyone else for some reason has yellow lights in their darkroom:

    I tested Ilford MGIV RC (Satin) up to 20 minutes (2, 4, 8, 12, 20) and could not see a single coin outline. I forgot to bring the original print with me but it's a neg I'm very familiar with. Didn't look one bit darker than normal, base still bright white, the only difference I noticed was how quickly the image came up in developer.

    I also tested Foma Variant III RC (Matte), only bothered going up to 12 minutes in 2-min increments because I already know the reputation. Yowza, I'm not even sure 2 minutes was safe, which was odd considering how easy the paper was to use. Base turned medium grey, only the 2-min and 0-min coin outlines were even visible. For the second test I turned on the other OC light that I don't normally use (in addition to the normal one), about 7 feet from enlarger, 8 feet from safebox/paper cutter, 10 feet from developer tray and pointed towards the ceiling so it's very dim. No coin outlines, print looked perfect. Quite dark in there that way though, not too bad for developing but impossible for writing notes.

    Was going to test my Fomatone WT RC but the package insert said yellow lights OK. I will probably test it next week anyway, though.