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  1. #11
    Photo Engineer's Avatar
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    Maybe the developers are not high enough in contrast. However, about 500 mg/L of Sodium Hypo is where I might start and work upwards. IDK what your level works out to.

    PE

  2. #12

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    Ok, I'll try lowering the hypo...

  3. #13
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    Quote Originally Posted by Photo Engineer View Post
    However, about 500 mg/L of Sodium Hypo is where I might start and work upwards.
    Ilford recommends from 8-12 grams/liter. What's up with that?

  4. #14
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    I said start there and work up! I cannot figure out from the data supplied what the actual current value used amounted to.

    The effect of hypo is generally at zero, blocked or dark highlights and excessive contrast. As you go up, contrast becomes normal and the highlights clear. The reasoning is that you must develop all of the silver necessary in the negative Dmax and without doing that, the reversal process will develop some and darken highlights in the transparency.

    You have to fiddle with it if you are starting from scratch.

    PE

  5. #15
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    As I've said before, using Ilford's recommendation of 8-12 g/l on Agfa APX100 resulted in complete removal of image when I tried it, while zero hypo worked. So I'd agree that 0.5 g/l would be a better starting point...

  6. #16

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    Infact I've just returned from my basement, where I've reversed another strip of Apx100. This time WITHOUT hypo, lengthening the first developer time to 15min (18°C). It works sufficiently well. I must say the highlights are somewhat foggy and the overall tone is on the warm side, light brown, as opposed to a cool tone of my first attempt.

    Summing up:
    1) 4g hypo/400ml and 12min/19°C f.d. --> cool tone, highlights clear but somewhat blown out;
    2) zero hypo and 15min/18°C f.d. ---> warm light brown tone, highlights a little on the foggy side but not blown out.

    Tomorrow I'll try adding as little hypo as I can (say 1g hypo/400ml).
    Last edited by Alessandro Serrao; 10-18-2010 at 05:48 PM. Click to view previous post history.

  7. #17

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    The buffered stannous chloride solution gets cloudy only after being used.

  8. #18

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    http://www.flickr.com/photos/54029037@N05/5096395976/

    This one's omitting entirely the hypo and the last selenium toner bath.
    As you can see the highlights are quite muddy but not blown out.Blacks are richer due to the abscence of hypo; surprisingly they aren't affected much by the selenium toner.
    The slide has an overall light brown cast not visible on this scan...

    Next: I'll try to put 500mg of hypo...

  9. #19

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    Hello!

    There is a lot of information and formulas on reversal processing spread on the Internet. Still, I miss a complete comprehensive guide to on the process which is tested and used by more then one photographer. There were some attempts to do that (some of them quite good) but it is still hard to adjust these processes for different films.

    I would love to have a "Process" with a list of films and developing/bleaching times and other info on results... or at least a guide how to perfectly adjust the process for each different film. I believe the info is all there but it would be great to put the pieces together and make a consistent resource for others.

    Who's in?

    In fact I wish more people would shoot b&w slides. I find it much more appropriate to many photographer's situation than negative/positive process.

  10. #20
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    Alessandro, this is a very illustrative of the effects of hypo. Thanks for your pragmatism and posting the scans as well. I'll be anxious to see where the happy median lies.

    I plan to cut my teeth soon on reversing 4x5", so this is great. I'm in.

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