Results 1 to 8 of 8

Thread: Test Targets for Dialing in B&W Development

  1. #1

    Join Date
    Sep 2020
    Location
    San Francisco
    Posts
    75

    Test Targets for Dialing in B&W Development

    I've been playing with 510 Pyro with x-ray film and I'm trying to dial in ISO in different types of light, dilutions and development time. I've been creating stacks of the same photo of a sculpture I own lighted such that it has bright and dark sides, bracketed -1/0/+1 and targeting ~7 min development time. I have gotten to a point where I'm getting a reasonable negative but I think my current approach is too ad-hoc and I need to do something more controlled for the test target.

    What are some good ways to approach this?

    What do folks use for a test target?

  2. #2

    Join Date
    Sep 1998
    Location
    Oregon now (formerly Austria)
    Posts
    2,700

    Re: Test Targets for Dialing in B&W Development

    I like real-life subjects with a full range of tones and clear areas I can read easily with the spotmeter and place where I want them. Examining shadow detail tells the story on E.I., and seeing if the highlights fall correctly indicates development-time tweaks. Using a real subject with real lighting and both light and dark tones automatically takes lens and in-camera flare (which is a significant factor!) into account. Using a grey card or the like doesn't. Your sculpture may be just fine.

    Remember it's not rocket science; we only need to get exposure full enough for the shadows we want and development close enough so that our contrast controls in the darkroom are adequate to make a fine image.

    Best,

    Doremus

  3. #3
    ic-racer's Avatar
    Join Date
    Feb 2007
    Posts
    5,814

    Re: Test Targets for Dialing in B&W Development

    Meters are calibrated to give an exposure to the film so the darkest parts of an excellent print have a slope on the H&D curve of three-tenths the slope of the straight portion of the curve. A super easy way to approximate this is the ASA method, whereby you can expose a uniform target to Zone I. If the processed negative cuts 1/3 of a stop more than a blank frame when placed over your meter, the settings to make the exposure were OK.

  4. #4

    Join Date
    Sep 2020
    Location
    San Francisco
    Posts
    75

    Re: Test Targets for Dialing in B&W Development

    Doremus and ic-racer, thanks for the tips. I'll try both directions.

    I think I need better control of the lighting. The tricky part is that the film responds differently to different light because it's not panchromatic. Mid day ISO will be different than early or late in the day or artificial light. I might go with the uniform target to test the different ISOs and the introduce a more realistic target to verify and fine tune.

    Thanks to both of you for pointing out that the exposure is for the shadows / zone I. While I know that and practice it when shooting, I somehow lost sight of it for this test.

  5. #5
    ic-racer's Avatar
    Join Date
    Feb 2007
    Posts
    5,814

    Re: Test Targets for Dialing in B&W Development

    Placing a diffusion sheet on the inside of a window works. If you move in close to frame it make sure the lens stays on infinity.

  6. #6

    Join Date
    Sep 2020
    Location
    San Francisco
    Posts
    75

    Re: Test Targets for Dialing in B&W Development

    ic-racer,

    For the ASA method, how does development time play in?

  7. #7
    ic-racer's Avatar
    Join Date
    Feb 2007
    Posts
    5,814

    Re: Test Targets for Dialing in B&W Development

    Quote Originally Posted by sabeluc View Post
    ic-racer,

    For the ASA method, how does development time play in?
    To be exact, ASA specified development to achieve a specific point on an H&D curve. But for first time testing, consider that development has minimal effect on Zone I.
    So, set your exposure index first, with a Zone I shot, then work on development time. When you have your development time you can go back and re-check the Zone I and see if it got lighter or darker based on your development time.

    To keep expand on this KISS method. You would expose a Zone VIII image at your EI determined above. Make a print of minimum exposure to produce maxiumum black on the film base. Place a coin on the paper and expose the Zone VIII frame with those same settings on the enlarger. If you just see an outline of the coin, negative development time to match that paper is good.

  8. #8
    ic-racer's Avatar
    Join Date
    Feb 2007
    Posts
    5,814

    Re: Test Targets for Dialing in B&W Development

    When I first did this in the 1970s, I went hog-wild with minimum exposure for maximum black and wound up with negatives developed to way too high gamma. In real life, you can probably go with the enlarger exposure of the film base that has just at touch of gray. Otherwise the method will lead you to too much development time, compromising the mid tones.

Similar Threads

  1. Studio exposure/development test for black and white film illuminated with strobes
    By Peter De Smidt in forum Lighting Techniques - Studio, Artificial
    Replies: 25
    Last Post: 24-Sep-2015, 07:43
  2. Replies: 14
    Last Post: 13-Aug-2015, 12:35
  3. IT8 targets
    By Rider in forum Digital Processing
    Replies: 25
    Last Post: 11-Oct-2011, 01:23
  4. Dialing In Shadow Detail w/ a Chromira Print
    By Peter York in forum Digital Hardware
    Replies: 2
    Last Post: 20-Jun-2010, 14:49
  5. Development time for Acros 100 in Tmax RSm test
    By Stephen Sample in forum Darkroom: Film, Processing & Printing
    Replies: 2
    Last Post: 29-Jul-2006, 22:02

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •