This is a biginner's question for you old timers.

Discussion in 'The Darkroom' started by Grandpa Ron, Feb 27, 2019.

  1. Grandpa Ron

    Grandpa Ron No longer a newbie, moving up!

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    I recently restored some of my late uncles camera gear.

    In Phase one, I developed a dozen or so 4x5 black and white films from his old view camera. I scanned them into the computer and the post processed images were quite nice.

    Phase two, I am going to contact print them on his 1940's vintage "Kodak ABC Photo-lab" contact printer. The instruction booklet says how but does not give any exposure times. All it says to do is to double the previous time until the photo image comes out correct on the paper. So the obvious question is how long of an exposure should I start with.

    The box is about 8x10 and painted white inside, the glass will hold a 4x6 negative. It has a 7 watt bulb inside and appears quite bright. I plan to use a black slide to expose 1/4th of the sheet at a time, so the question is, what is your best guess a starting exposure time? Do I do 1, 2 4, 8, seconds or 10, 20, 40 80 seconds?

    I have never contact printed negatives and it has been 30 years or more since I last used an enlarger. My first impression is to start with #3 arista EDU paper for a bit of B&W contrast but I certainly welcome any and all advice.

    Phase three is to restore my uncles late 1930's "Kodak Auto-focus" enlarger, but that is a long way down the road.


     
  2. Peeb

    Peeb Semi-automatic Mediocrity Generator Supporting Member

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    I can’t educate on that but what a cool project!
     
  3. petrochemist

    petrochemist TPF junkie!

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    Exposure times will depend on the paper used & developing process (chemicals/concentration/temperature /time) so I'm not surprised they don't quote exposure times.
    I'd guess the 10, 20... series would be more appropriate as a starting point with typical development, but it's a VERY long time since I did any darkroom work (~40 years) and that wasn't conventional stuff.

    You could just use a 1" wide strip of paper in your dark slide to give you more experiments from a single sheet of paper. This gives you multiple trys from a single sheet with the ability to update the 2nd set based on the results of the first...

    There are quite a few old photography free e-books on www.archive.org which should give good instructions on darkroom technique, searching terms like 'Kodak', 'darkroom processes' should give you a good selection :)

    IIRC a 7W fluorescent produces light roughly equal to a 60W incandescent. If exposure times are down around 1s, I'd switch to a dimmer bulb unless you have a timer in the lighting circuit. Manually getting times of 1-2 s repeatably is not realistic IMO.
     
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  4. wsetser

    wsetser TPF Noob!

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    Pick any time you want, I'd probably start around 20 seconds, and expose a test strip. Develop the strip and and evaluate it. If it's very light, try a much longer time, if it's a little, light try a little more time. Conversely, If it's very dark, try a much shorter time, and if it's just a little dark try a little less time. It might take a while to zero in on the first print, but if your negatives are fairly consistent, it should be a lot easier.
     
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  5. MartinCrabtree

    MartinCrabtree No longer a newbie, moving up!

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    If you use strips for economy pick a part of the negative with the largest spread of denisty for lack of a better word coming to mind.
     
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  6. dxqcanada

    dxqcanada Been spending a lot of time on here!

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    Hmm, 7W bulb ... I am used to bulbs of much higher power, so I remember doing contacts with just 5s or less.
    You would have to just try some strips starting with 10s and then document ... times based on visual density of the negative and how the print comes out.
     
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  7. webestang64

    webestang64 Been spending a lot of time on here!

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    Go get some darkroom books, they are cheap and plentiful.
    These cost me $2 each.
    [​IMG]
     
  8. Christie Photo

    Christie Photo No longer a newbie, moving up!

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    GOOD plan. I'm thinking I'd go 5, 10, 15, 20.

    Let us know how it all works out.

    Have fun!
    -Pete
     
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  9. ac12

    ac12 No longer a newbie, moving up!

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  10. vintagesnaps

    vintagesnaps Been spending a lot of time on here!

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    Who's an old timer??! lol I agree on the 5-10-15-20 and doing test strips to not waste too much paper while you're getting exposure times figured out. Obviously it's different projecting from an enlarger in a room under the glow of a safelight to try to compare to using a bulb in a little metal box.

    Have fun.

    A couple of those darkroom book covers are groovy.
     

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