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  1. #21
    Ian Grant's Avatar
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    Try this page, was listed yesterday and is still listed today. Scroll down the page. Photocolor II

    Yes unfortunately the Champion relocation ended production of all Paterson photo-chemicals until the recent link up with Calbe for B&W chemicals. A little known fact is that the original manufacturer of Paterson chemicals was Ilford !

    Ian

    Quote Originally Posted by pentaxuser View Post
    A
    I couldn't find any mention of Photocolor on the Retro site.
    pentaxuser

  2. #22
    Photo Engineer's Avatar
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    AgX;

    I always use a prewet in a tube processor, but do not in rubber tank or tray processing.

    The reason is one of tempering and of getting even development. In a tray, for example, it is easier to dunk the sheet in at once, but with a drum, there is an initial swirl pattern on dry film that is not present with wet film.

    I've tried all combinations, and now feel that the stainless racks in tanks should also get a prewet based on the initial temperature shock of the relatively cold stainless hitting the developer.

    A prewet certainly does no harm to the film that I have ever detected.

    As for a blix for film, I have seen considerable degradation of colors due to blixes which leave in some silver. I have seen poweder blixes using sodium salts that are very weak indeed in bleaching film.

    I have seen the effects of silver on grain and surprisingly it makes it worse sometimes instead of better as you might expect from experience with staining developers. I would think that the grain would be better, but it is the way the grain is distributed unevenly in dmax areas that show it up in prints.

    In any event, I'm still working on this problem. It is very hard to make a stable active blix for film. It may appear to remove silver, but if the level is much above 1 or 2 milligrams per square foot, you can see it in the highlights of the print as increased grain.

    Over exposure makes it worse.

    I'm sorry for my comment about my experience, but I was trying to emphasize the fact that I have worked almost fruitlessly on this effort for a large portion of my life and have seen others sell these 'film blixes' when I have mixed the identical blix in the 60s or 70s and found that it just is not effective.

    I have found additives that will work, but they are either toxic or expensive. For example, adding about 20 g/l of thiourea to such a blix will make it quite effective, but thiourea is a carcinogen and is banned in some states. Our efforts in this can be seen in the patent. The cost or toxicity are issues that ruled a blix out for Kodak and Fuji. As I said, I cannot speak for Agfa. But, at the start, Agfa didn't sell one either.

    PE

  3. #23
    Ian Grant's Avatar
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    Ron, the blixs used in the best amateur C41 kits are far better than those you may have worked on for the old dunk dip, and roller transport machines for one simple reason. They aren't used to anything like their full potential capacity and they aren't replenished.

    Cost is far less of an issue with Blixs in amateur kits where the major costs are the packaging, transport. So a formula un-economic for commercial use can be more appropriate for an amateur kit.

    Ian

  4. #24
    Photo Engineer's Avatar
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    Ian;

    All of the blixes that we tried were fresh mixes and used one time only for the film in question. We exposed sensitometric strips from dmin to dmax and measured the density and the retained silver.

    We also measured sharpness, grain and leuco dye formation.

    Color reproduction studies were done with undercut and double undercut images.

    None of the blixes that we made, when used fresh, made the cut except for the ones in the patent. I see none today that offer anything new. They are all either ammonium or sodium ferric EDTA and sodium or ammonium hypo at a pH of about 6.5.

    There was, at that stage, no consideration of deep tank use, roller transport or anything including cost. That came later when every possible approach came under review. So, while I appreciate the comment and understand it, you are looking at it backwards from the way we actually did the R&D.

    I really do wish there was a good blix out there, but they all follow the same pattern. I have had samples of all of them including many now defunct versions. I have the original Agfa paper blix here in a packet unopened left over from early experimentation, and I just disposed of two Japanese blixes by using them for color paper, but not film.

    I used to get samples of these from everywhere and everyone. All got tested for paper and film, but not in seasoned or mechanical processes as you mention. Only if they survived this first cut did they go on for machine testing. They were all compared to our own blixes and bleach then fix technology for image quality.

    If any passed our test, they went to Photographic Technology for testing in the continuous machines to see how they survived in a real world situation. Most all that got through the first cut failed there. We then had to fall back to the bleach then fix situation.

    I have reams of patents on bleaches and blixes and stll remember some of the hallmark numbers such as BP 991,412. ( I think I got that right)

    We also studied patents on removing metals from ores to see if there was any technology there. There was, but it would not work in film. We even had special chemicals synthesized, and just before his death, Keith Stephen was working on a new silver halide solvent that might have done the job.

    As far as bleaches go, we worked with quinone, persulfate, Ferric ammonium citrate and chloride, copper salts and etc. None worked well either as a bleaching or blixing agent for one reason or another.

    So, the best amateur C41 kits are nothing more than things I saw over 30 years ago. I stand by this. I see nothing new here, truly I do not.

    PE

  5. #25

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    Quote Originally Posted by Photo Engineer View Post
    If you do not use a stop, don't rinse. Go directly into the bleach. I suggest prewet/develper/stop/bleach/wash/fix/wash/stab or prewet/developer/bleach/wash/fix/wash/stab.

    A water rinse after the color developer with no stop can introduce crossover.

    PE
    Could you please elaborate on the wash/crossover issue? I never heard that one before; and I have a wash cycle programmed into my ATL-3 in order to prolong the life of my bleach...

  6. #26
    Ian Grant's Avatar
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    Ron, while what you say makes sense it doesn't equate with the reality that I experienced with over 25+ years use of the Pip Pippard designed Photocolor II C41 kits, and his Chrome 6 (E6) kits or the experiences of many thousands of others.

    Pippard was acknowledged to be an extremely good photo-chemist and was instrumental in the design & formulation of many of the well known Johnsons (Scale Brand) B&W photo-chemicals. Later he formulated the company's extremely successful range of Colour chemistry.

    He surprised many people with the simplicity of use of his colour chemistry, cutting the number of baths to a minimum without losing any quality in the final negatives, slides or prints. So its sad to see Paterson no longer making his chemistry.

    Ian

  7. #27
    Photo Engineer's Avatar
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    Ian;

    All any of us can do is comment from our experiences. I understand what you are saying as well, and can only recount my own experience.

    PE

  8. #28

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    Quote Originally Posted by Ian Grant View Post
    Try this page, was listed yesterday and is still listed today. Scroll down the page. Photocolor II

    Yes unfortunately the Champion relocation ended production of all Paterson photo-chemicals until the recent link up with Calbe for B&W chemicals. A little known fact is that the original manufacturer of Paterson chemicals was Ilford !

    Ian

    Ian Thanks for that. Just as an experiment I then went to my bookmarked Retro site and googled it as well. In neither case could I find any reference to Photocolor II under Paterson on the site but then did a search on the Retro site under Photocolor II and up it came.

    So it doesn't seem to be listed under Paterson - that only B&W chems but it is under the Photocolor name and then it mentions Paterson. It's the only part of the original Paterson chems. There's no blix or any RA4.

    So I assume it's the last of the line. I can only assume that it must be within its sell by date otherwise Retro would not list it but my understanding of how long ago it is that this developer was last made for Paterson makes me wonder about it. I had always understood that even in an unopened state liquid colour developer has a limited life.

    Still good value at the price but only if it retains its full potency

    PE What's your belief about how long unopened liquid colour developer is likely to last?

    Thanks

    pentaxuser

  9. #29

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    Thank you all for your great advice and wealth of knowledge. This discussion has certainly helped me out. I am going to try my hand at developing my film. I think that I have a good idea of where to start and once I pick up one of the kits, then I think I will be well on my way. Thanks again!!

    Phil

  10. #30
    Shypii90
    Yeah I don't think Phil is alone; I also found this thread very interesting!
    Thanks to everyone! And Scuba_Phil of course for starting it in the first place

    I'm sure it will be a great thread for newbies like us to research on before actually practicing!

    Cheers
    Shawn

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