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  1. #11
    Bill Burk's Avatar
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    Hi Tom1956,

    Yes, most films there are plenty of advice where to start, definitely you want to pick a time around 5-10 minutes - or maybe 15 minutes but I don't know where to start with X-Ray film and the developer you want to use... You could ask that specific question and some people may know...

  2. #12
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    http://www.largeformatphotography.in...and-comparison

    Mucho info on x-ray film development.
    Rick A
    Argentum aevum

  3. #13
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    Like Bill pointed out, always get the exposure index first. Then do the development test.
    Development test is best done in darkroom with your favorite paper and enlarger light source. Project a processed (first guess at development time) Zone VIII negative with your enlarger so the film base is also showing. Adjust enlarger exposure so the film base just prints black with the least exposure possible. Place coin on white area of the printing paper. If you can see outline of the coin, development is correct.

  4. #14

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    It could be that I am thinking along the lines of a misconception, but it has been my observation that the better photographic minds seem to congregate on this site, perhaps with no more providence than a group of tumbleweeds. Still, I find myself bringing thoughts that the other sites have long fruitless threads about, and seem to find better focus here on the final answers.
    All this said, I believe I've conceived a test that will require my having to develop (sacrifice) only 2 full size 8x10 sheets of film and glean everything I need to know on both exposure and development time. Just on the ideas advised in this 14 post thread, my thoughts are in order on the test procedure I will be carrying out this weekend. From that, I fully expect to be able to load up film holders and go out shooting with confidence. To give clue as to the idea I have in mind it to use the T-square and triangle to fabricate alternating "dark slides" to arrange 8 tests on the same sheet, one as exposure test, one as development time test. Actually 3 sheets will be used. The third to shoot the broadside of my house, which is a rural scenic view in itself. In the next 3 months I am going to shoot up 97 pieces of X-Ray film that only cost $29.00 including shipping. Hey, thanks everybody.

  5. #15

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    Quote Originally Posted by ic-racer View Post
    Shoot any uniform surface without texture illuminated by light you normally use (ie tungsten vs daylight). Focus lens at infinity. Shoot zone I. Place processed negative over light meter, the frame that drops exposure by 1/3 stop = 0.1 log d = good exposure index.
    OK I set up and did this test yesterday but the results were inconclusive. Just to be sure I have this straight, I am testing for a film speed bu making 8 exposures between ASA 40 and 160. So I am to meter on my big piece of cardboard for each film speed and close down by 4 stops? Thank you.

  6. #16
    Bill Burk's Avatar
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    Quote Originally Posted by Tom1956 View Post
    OK I set up and did this test yesterday but the results were inconclusive. Just to be sure I have this straight, I am testing for a film speed bu making 8 exposures between ASA 40 and 160. So I am to meter on my big piece of cardboard for each film speed and close down by 4 stops? Thank you.
    Yes exactly. If your results were inconclusive, make bigger differences that will be easier to see: For example you could try EI 3 6 12 25 50 100 200

  7. #17

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    Development controls contrast. It would be difficult to tell what was proper development by looking at a photograph of a uniform surface. Ideally, you might set up a patchwork of cards which reflected light as Zones 1, 3, 5, 7, and 9 (or, more realistically, 2, 4, 6, and 8). Photograph them a couple of times, cut up the film, and develop as mentioned. That way you could get an idea of speed (from the low value) and contrast at the same time.

    You used to be able to buy packages of reflection gray scale which were ideal for things like this. I don't know if they are still avaliable.
    Last edited by nworth; 08-25-2013 at 03:48 PM. Click to view previous post history. Reason: Add note on reflection gray scales

  8. #18

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    When I set up my process for 4x5, I placed a Stouffer step wedge in a film holder on top of a sheet of film. I then found a large uniformly lit outside wall, metered the wall, opened up 4 stops, exposed and developed. This one neg helped me home in on my film exposure and development and told me more than any advice I'd read in magazines (what we did before the internet). Eventually I picked up an old densitometer and really calibrated everything. Now I'm coming back after a decade long hiatus and I'm starting all over again with new films, new developers and new papers.

  9. #19

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    Quote Originally Posted by jerrybro View Post
    When I set up my process for 4x5, I placed a Stouffer step wedge in a film holder on top of a sheet of film. I then found a large uniformly lit outside wall, metered the wall, opened up 4 stops, exposed and developed. This one neg helped me home in on my film exposure and development and told me more than any advice I'd read in magazines (what we did before the internet). Eventually I picked up an old densitometer and really calibrated everything. Now I'm coming back after a decade long hiatus and I'm starting all over again with new films, new developers and new papers.
    So which step in the Stouffers' wedge did you use that determined your film speed?

  10. #20
    Bill Burk's Avatar
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    Quote Originally Posted by Tom1956 View Post
    So which step in the Stouffers' wedge did you use that determined your film speed?
    If you plan to use a Stouffer step wedge, then you change the procedure significantly and you open the door to better testing. A step wedge gives better tests than if you do camera tests exposing for Zone I. I personally contact a step wedge to light in a sensitometer, which is basically a box that aims a flash at the strip.

    On your original plan of tests for Zone I, one of the sheets would have hopefully measured close to a density of 0.10 and the EI speed you shot that film at is what you would consider your tested speed.

    When you use a Stouffer step wedge, depending on the one you buy, the difference between steps is 1/3 or 1/2 stop each. So hopefully, when you exposed a step wedge, one of the steps of your developed film measures close to density 0.10 - You can count the steps to arrive at how many f/stops of light are blocked (you can do that in your head)... Or you can do some math using the known density of that step to account for how much light was blocked by that step.

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