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  1. #1

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    RA4 Chemicals and B&W Film

    I arrived home to find out someone had dropped off a couple of boxes of RA4 chemistry. Now I do not process color film or paper but was wondering if this could be used for B&W film processing or should I just sensibly dispose of the chemicals?

    I was reading an old Darkroom magazine article and the author was recommeding developing Tech Pan in C41 chemistry for pictorial use, so maybe the RA4 developer could be used as a low contrast developer? And what about the BLIX - could that be used to fix regular film?

    Mike

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    Did they give you blix? Or a bottle of bleach and a bottle of fix? It's likely a fix and bleach to be mixed together to form blix. OTOH it might not be labelled that way -( The fix should work peachy for B&W film.

    On the dev how much is your time worth? You could do some testing.

  3. #3

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    RA-4 is print chemistry for color prints (as you probably know). Totally not suitable for film of any kind. The blix would completely remove the image from b/w film, as it is intended to remove all silver from the final color print leaving only dyes. B/W film image is composed of developed silver.

  4. #4
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    The developer should give a low contrast silver image with the RA developer, but I wouldn't hazard a guess as to the time to use. Proably about 10 minutes or so at 68F.

    USE A STOP. The carryover of color developer can be much more than with B&W developers.

    The fix part of the blix (the clear part) will work fine with film. Use 2x the time needed to clear the film.

    Wash the film as usual and treat with photo flo. If you omit the stop, you may need about 3x the normal wash time to get the color developer out of the film.

    PE

  5. #5
    Ian Grant's Avatar
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    As Ron knows back before film emulsions improved significantly 35mm users tried everything to minimise grain.

    Some of the finest grain developers were based on colour developer agents usually with a loss of film speed of between 1 & 2 stops.

    By the time I began serious photography films like FP3 and HP3 were the norm and these developers had gone back out of favour, so I never tried them.

    Give it a try but don't expect too much.

    Ian

  6. #6
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    Ian;

    Yes, ppd based developers are quite good, but the RA print developer was not designed for use with a film, so IDK how it will do for grain, speed or sharpness.

    A good HA developer could be designed by using an accelerator with the ppd or a coupler which will turn it into a new class of staining developer. This could give both fine grain and good sharpness. IDK.

    PE

  7. #7
    Ian Grant's Avatar
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    We touched on this before Ron.

    A developer formula utilising a colour developing agent, with a colour coupler added would have a lot of potential for fine grain and good film speed, but it would need some experimentation to get an optimum balance of acutance, sharpness, fine grain & film speed.

    For those not sure what we mean essentially we are talking about developing a B&W film chromogenically like XP2, but instead of the coupler being in the film its in the developer, similar to Kodachrome. So you get a silver image amplified by the dye image.

    The process is superb for negative intensification too. Before digital the Astro-photographers looped C41 films. This means develop in C41 dev then fix, wash - bleah in a re-halogenationg bleach, re-expose to light re-develop in C41 dev, fix ----- the cycle repaeted quite a few times before finally bleaching & fixing.

    Maybe this is a winter project for me. A better dev than C41 is needed, but theres plenty published to use as a start point.

    Ian

    Quote Originally Posted by Photo Engineer View Post
    Ian;

    Yes, ppd based developers are quite good, but the RA print developer was not designed for use with a film, so IDK how it will do for grain, speed or sharpness.

    A good HA developer could be designed by using an accelerator with the ppd or a coupler which will turn it into a new class of staining developer. This could give both fine grain and good sharpness. IDK.

    PE

  8. #8
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    Ian;

    You can speed up ppd development by adding citrazinic acid or H acid to the developer and adjusting the pH back up. This gives no color to the film, but makes the ppd more active.

    PE

  9. #9
    Ian Grant's Avatar
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    What's H acid Ron ?

    Ian

  10. #10
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    Ian;

    It is a 'colorless' coupler like citrazinic acid. It used to be sold commercially by several companies as it is a rather simple napthol derivative with a lot of commercial uses. It is used in some color reversal developers today instead of citrazinic acid IIRC.

    PE

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