That's great news.
I'm waiting impatiently for the process to be revealed.
I'm waiting impatiently for the process to be revealed.
DR5 getting published?
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Thanks BradS and wyofilm. That would seem to make sense, well to me anyway.
pentaxuser
pentaxuser
Yes, "a good customer service experience" would be appreciated. After sending film to DR5, and then hearing nothing for over a month, I sent what I thought was a polite inquiry requesting a status update. His reply was overly defensive, dismissive, and quite rude. He suggested my inquiry was a waste of his time, and that if I don't want to wait however long it takes, I should stop sending him film.
Out of genuine concern for the survival of his business, I politely suggested he find someone else to provide customer service, someone who has a better temperament for it.
Then, early this year, there was a nasty incident in which he falsely accused me of posting something about DR5 on Yelp. His accusation was based on nothing more than the coincidence of that person living in the same city as I do (population about 168,000), and that person apparently had some business dealing with some other person who has the same last name as mine (it is a common surname). In his email to me, I was called a Nazi and threatened with repercussions if I did not remove the Yelp post. By the time I got his email, the offending Yelp post had already been removed, so I never saw it. I'm not sure I was completely successful in trying to make him see his mistake, and he never did really apologize for it.
If someone is really good at what they do, I am willing to tolerate a certain amount of gruffness and eccentricity, but as a customer, I can put up with only so much abuse. From DR5, I've had more than my limit.
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IIRC Dr. Wood has said in this forum that 1) his process doesn't use halide solvents in the first developer and 2) he uses a fogging second developer but not Dithionite. Furthermore, his pipeline has a mysterious last step labelled FT. Also, PE who probably knew everything about DR5 process has said in one of his posts the following: "The DR5 process uses a unique chemistry that was acquired via experience and testing and does not match any kit currently available." It will be interesting to find out what this unique chemistry is and whether it can be acquired by DIYers.
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I do B&W reversal development and love the results. I I am very happy with what I get when I do everything right, from in camera to projection. But I am always willing to try out something new for fun. I'm hoping that the process does not contain any hard to get or exotic chemistry. I would like to do a side by side to see the results. Hoping that we can get something soon (also hoping that there is no bad reason for the process being made public)
john
john
Notice the double bleach bath, in accordance to what Kodak says, and the last two steps, The last step PF should be the wetting agent (Photo Flo).
I feel the entire process should be calibrated not to damage the subbing layer of the film, because it's the subbing layer to fail and not the gelatine (or emulsion) that melts. In other words, the gelatine swells so much that it eventually detaches itself from the subbing layer. Hardeners expecially used as last steps aren't that useful to me.
The solution I feel is to minimize the wet time and the pH shifts of all bathes.
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Patents cant be used to undermine 'prior art', and all one has to do is submit 'prior art' to the patent office and the patent would be repealed.
Yes, if it is a dye coupler in solution + colour developer to make chromogenic positive on top of a silver positive, in order to help stabilise the dyes, its the idea I had when thinking of a way to increase dMax, the recipe I released however uses catechol instead as a staining developer to create a positive image stain to enhance dMax, as its simpler and easier for most people to do (and get the chemistry).
This is a very interesting hypothesis and could very well be the explanation for the unreasonable high DMax of DR5 process! Would a color coupler in the second developer work even when the second developer is a fogging developer? There doesn't seem to be a light exposure step in DR5 process.
I think this is way beyond David Wood expertise...
I dont see why it wouldnt. Unless the chemical fogging agent interacts with the dye coupler. You have to fog the image in order to get it to develop either way. I am sure I am not the only one thats talked about doing reversal with couplers for increased dmax on here and other places before, so it would be 'prior art'. Catechol works very well to increase dMax too, it was simple and I was happy with how it turned out. You could 'rehal' these methods, and use a ferricyanide and potassium bromide bleach to bleach back the positive silver image to silver halide, and re-develop for more dye or stain as well.
Other option would be to have some kind of chemical that causes stain in the presence of oxidised developer, same way a dye coupler works with a colour developer. Catechol does that directly. I remember hydrogen peroxide used in some old colour developer recipes in order to get a good colour image result. Hydrogen peroxide with a colour developer and coupler or with catechol might increase the image stain formed? Would be something to try and hydrogen peroxide is easily available.
Also potassium alum creates a stain with oxidised catechol, so it would in theory create more image stain when used with catechol. Its also used as a mordant in fixing dyes to various materials. Perhaps its able to be used in conjunction with dyes and a developer rather than needing a colour developer and dyes? No idea.
Aminophenols are used in hair dye products for colour hair dye. Typically p-aminophenol. Which is mostly what our Parodinal is. It also works by oxidative dye formation as far as I know, in hair dye, it oxidises slowly after you mix everything together and transfers dye from that. In in developer, our film oxidises the developer, so we wouldnt use an oxidising agent to get the dye, as we only want it oxidise and form dye proportionally where its developing the image. I might look into it when I get some chems and equipment again, I already have some b&w negs I could try bleaching and re-developing.
I feel it's much simpler than that (judjing from the Dr5 Tecnolab d&d machine display), maybe a simple final toning step (either gold, selenium or whatever)...
@Ian Grant had some time ago posted a list of color couplers that could be used with color developers for toning prints. alpha-naphthol is the one that produces blue tone IIRC. I guess some combination of the basic color couplers would give black tone.
I am just thinking, a copper sulphate bleach alters the colour of colour film a bit when used, so perhaps it leaves some copper compounds in the film despite sulphite and washing?
Perhaps after a copper sulphate bleach and clearing, we could use a silver nitrate solution to increase silver density.
Its possible to do it with aminophenol too. But with the right couplers I think. Like in hair dye products. Or azo dyes. If the couplers in hair dye products are not mixed with an oxidiser, it might be possible to use them directly from the product itself. Also some time ago I did some experiments on Aminophenol and Rodinal on colour negative films, I found that it actually developed colour on C-41 films. I only ever noticed this by inspecting the film after developing and stopping but before fixing. I could see the colour very strongly on the surface of the unfixed film of colour charts. Bleaching and fixing would remove 99% of it. As would fixing (but at least thered be an image). I might try this again at some point with a mordant or formalin even perhaps.
Perhaps after a copper sulphate bleach and clearing, we could use a silver nitrate solution to increase silver density.
Its possible to do it with aminophenol too. But with the right couplers I think. Like in hair dye products. Or azo dyes. If the couplers in hair dye products are not mixed with an oxidiser, it might be possible to use them directly from the product itself. Also some time ago I did some experiments on Aminophenol and Rodinal on colour negative films, I found that it actually developed colour on C-41 films. I only ever noticed this by inspecting the film after developing and stopping but before fixing. I could see the colour very strongly on the surface of the unfixed film of colour charts. Bleaching and fixing would remove 99% of it. As would fixing (but at least thered be an image). I might try this again at some point with a mordant or formalin even perhaps.
Did you mean using Copper Sulphate bleach after second development? If yes then you could instead use a Dichromate intensifier (which is essentially a rehalogenating Dichromate bleach that leaves some Chromium compound in the film). It adds some density to the silver image on its own. Maybe together with Silver Nitrate it can do even better.
Yes, and silver nitrate becomes silver in the presence of copper and copper takes on the nitrate. If there’s some imagewise copper. But yes that should work so me the chromium should be in the form of the image. Now if we could recycle the silver from the reversal bleach instead of spending money on silver nitrate that would be pretty good
Perhaps that is simple as adding sodium chloride to the used bleach to turn the sulphuric acid into hydrochloride acid. And use that as an intensifier, dichromate + HCl + silver sulphate
I'd suspect that it's splitting apart some part of the process that's normally done in one step (in the FD most likely) - possibly by attempting to reduce silver solvency in the developer to increase nominal Dmax, then using a highlight bleaching step after second development to try & clarify the highlights.
The double bleaching bath is nothing more than the same belaching agent duplicated, much like double fixing steps.
I'd agree - I don't think DR5 is anything like as sophisticated as people want to believe (otherwise there wouldn't have been chemical process issues that required consultation with photographic engineers) - but I was referring to the mystery final treatment bath(s) - and what they might do.
Yes, and silver nitrate becomes silver in the presence of copper and copper takes on the nitrate. If there’s some imagewise copper. But yes that should work so me the chromium should be in the form of the image. Now if we could recycle the silver from the reversal bleach instead of spending money on silver nitrate that would be pretty good
Perhaps that is simple as adding sodium chloride to the used bleach to turn the sulphuric acid into hydrochloride acid. And use that as an intensifier, dichromate + HCl + silver sulphate
Turns out there is a fairly simple intensification technique for silver images using dyes! Haist discusses a Leitz formula that uses a Copper Sulphate bleach and dyes like Methylene Blue which gives impressive intensification going by the graphs. If DR5 is using some such process, it's no surprise that he gets impressive DMax. Archival stability is uncertain though.
Subproportional reducer? FT is Ferricyanide-Thiosulphate then. Not quite unique chemistry.
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As I understand, the ft reducer would lower the DMax...Subproportional reducer? FT is Ferricyanide-Thiosulphate then. Not quite unique chemistry.
Interesting, concept, wonder why I never heard about it before. Maybe because it is called "Chrome" and I ignored it because I have not exposed color for 30 years. Seems that once the negatives are processed reversal, you can't print them on paper anymore. I have always made positives for display with continuous tone ortho from negatives. Much more control that way, plus you can make paper prints too. Or are people doing slide-shows, where the original size of the negative needs to be maintained to fit the projector?
It should be possible to enlarge the slide on sheet film to get a inter-negative and then contact print the inter-negative on paper. For colour slides, PE has described a method to get colour prints on RA4 paper.
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