Reverse development black and white

Ulf-Benno · 2014-11-25T16:47:44+00:00

Liebe Fotofreunde! € Durch den Preisanstieg bei den Farbumkehrfilmen habe ich mich wieder auf mein liebstes Hobby besonnen, der Schwarzweißumkehrentwicklun...

Ulf-Benno

Dear photography enthusiasts! € With the rise in prices for colour slide films, I’ve returned to my favourite hobby: black-and-white slide processing. Since 2005, when Chrome films were practically given away for free, I had put it on hold; now I have prepared the very last batch of A4105 developer from the Calbe chemical works and, with great success, developed some expired effke films and the new Silvermax into very beautiful slides. Unfortunately, the chemicals have run out, and I would like to ask fellow black-and-white reversal enthusiasts how to develop reversal-compatible films now. The choice is greater than ever. The article from the summer in ‘Photoklassik’ sounded very promising. However, it only referred to professional laboratories. € The films currently available and considered to be very good are: Scala, Fomapan R, Silvermax, CMS II, Rollei RPX 25, Rollei Retro 80S and Superpan200, CMS20, CMS20II, “Ortho 25” and Filmotec UN 54 The following also produced quite good results with the A4105: APX 100, AP25, FP4+, effke 25 and 50, Tri-X 400, “P0100”, ORWO UN32 and UN52, € I would like to briefly provide an abstract of my current knowledge and experimental findings: € The core of the process is the initial development using a very strong standard developer or paper developer and a gentle fixer (acid-free), usually potassium rhodanide. My experiments so far show that even Dokumol 1+3 (+6g of rhodanide per litre) does not achieve the contrast and sensitivity utilisation of the original A290 developer from the aforementioned A4105 development kit. Only the Fomapan R and the Orth 25 produce very good results with it. According to Ilford, simple thiosulphate (conventional fixing salt) can be used at a concentration of around 8 to 12 g/l instead of rhodanide. Furthermore, potassium iodide is also mentioned in the literature as an additive. € The bleaching agent potassium dichromate is now replaced by potassium permanganate. Sulphuric acid or sodium hydrogen sulphate is used as the acid. Shelf life is improved by the anti-calcification agent M19. I have tried out another idea. I now use vinegar as the acid; the shelf life is at least 6 weeks. Please never use hydrochloric acid – acute risk of poisoning! The smell of chlorine is appalling. € Sodium sulphite is used as a clarifying agent. However, it is very sensitive to oxygen. So always prepare it with boiled water, use it briefly and then top up the bottle with water again. As an alternative, Ilford recommends sodium disulphite. This is the acidifying agent for simple fixing salt. € For re-exposure, I unroll the film from the canister and expose it in front of a fluorescent lamp. This is the quickest method (20 sec.). At this extreme light intensity, the film turns black even before secondary development. In this way, underexposed films can be salvaged. For secondary development and fixing, I use the chemicals from photographic paper processing € I would be delighted if all users of black-and-white reversal developers would get in touch. Perhaps we can persuade the chemical industry and the photographic trade to start offering such a high-quality product as the A4105 again. The formula was published twice by Fotokinoverlag with very detailed instructions and explanations. Potassium permanganate is also discussed. If required, I could upload copies of this to the forum. € Best regards € Ulf-Benno

AchimBauer

Hi Ulf-Benno, I’ve only developed SW slides twice, years ago, but I’ve recently been having a bit of a look into the subject again. You’ll find most of the information on narrow-gauge film forums, along with plenty of recipes. Best regards, Achim

TiMo

Hi Ulf-Benno, I think I heard that something will be available in the not-too-distant future. ? Best regards, Tim

AchimBauer

Hi Timo, Hi Ulf-Benno, ? I’ve heard some rumours too, but what’s supposed to be coming is apparently a reverse transaction for securities. ? Regards, Achim

Renate

Hello, At Photokina, Klaus Wehner presented a reversal kit that works for both paper and film. I know he plans to launch the chemical kit, but I don’t know when that will happen. He commented briefly on this under the heading: [size=4]"Analogue enlargement from black and white slides[/size]". Best regards, Renate

HGR

Hello, I’m also waiting for Klaus Wehner’s reversal kit! I’ve already completed the exposures for the roll films; now I’m putting together the equipment. I have a question that’s on my mind at the moment. The best way for me to load roll films is onto Kindermann’s stainless steel spools, but those probably aren’t suitable for double exposure, are they? I still have some white reels made of opaque plastic – would those work? I also have a large Jobo reel made of transparent plastic; that would probably work, but winding roll film onto it is very difficult for me with this bulky reel, especially as it’s designed to hold two roll films one after the other. Does anyone have a better idea? Best regards, Hans-Gerd

jochen53

Hello, In principle, as well as double exposure, there is also the option of chemical reversal using a reversal bath – a special reducing agent that completely blackens the undeveloped and unbleached silver halide. For example, Kodak FD-70, which contains 2-thiobarbituric acid and sodium dithionite. I do not know whether Mr Wehner works with double exposure or chemical reversal.

Ulf-Benno

Thank you very much for your replies. € The A4105 development kit is also very well suited to photographic paper. The enlargements have the right contrast for the black-and-white slide. However, the images have a yellowish-brownish tinge and an unattractive paper texture shows through, which presumably varies from one type of paper to another. It should be better with PE papers. The consumption of chemicals is enormous, so it can only be recommended in isolated cases. € The narrow-gauge film forums are, of course, the first port of call for anyone seeking advice. However, narrow-gauge film users have less choice when it comes to film. It’s usually Fomapan R and TriX-400. Both films are undemanding to develop but aren’t particularly brilliant either. The original developer Foma LQR is very well suited to Fomapan R, but it has such a short shelf life that you have to use up the bottle in one go. If the concentrate bottle is approaching its best-before date, you must first carry out a test. In my opinion, this developer is unsuitable for amateurs. Other developers apart from the aforementioned A290 do not deliver the same brilliance. € The simplest solution would be if someone were to discover a ready-made developer that could easily be adapted for reversal development (by adding chemicals). The bleach bath is available at the chemist’s, the acid at the supermarket, and the sulphite is also listed by our host as an additive for Polaroid and lith development. This would significantly lower the barrier to entry for reversal film users, and sales of these high-quality films would increase. € The development kit from the Klaus Wehner laboratory is bound to be a highly optimised, multi-component chemical set that meets all environmental requirements, but may well put off beginners. € Incidentally, re-exposing any film in the can is no problem. If you don’t want to take the film out, simply place a lightweight hand lamp (from a car workshop) on the open canister and wait 15 minutes; for very tightly wound brands, perhaps 30 minutes. That’s always enough, even if the reels aren’t made of transparent plastic. € Best regards Ulf-Benno € €

haeberlein

I develop everything using Dokumol in a 1:9 dilution with potassium thiocyanate and potassium iodide, as well as a potassium dichromate-based Bleach bath. For the second development, I also use Dokumol, but without any additives. For the CHSII, I use an 8-minute primary development time; for the AGFA Scala, you need 16 minutes. I have developed all my narrow-gauge and 35mm films with this method and still do so today. € Oh, and I use a 500W lamp for secondary exposure for about 2 minutes. That’s perfectly sufficient. € Regards, Rene

HGR

Thank you very much for the tips on double exposure. But of course, that raises another question: ? Is it possible to overdo it with double exposure, i.e. to cause overexposure of the image? ? Many thanks in advance ? Hans-Gerd

haeberlein

No, you can’t overexpose it there. I do everything in the light after the Bleach bath and nothing’s ever gone wrong.<B>"Reverse exposure. </B>The silver halide remaining after bleaching – i.e. the part that was originally unexposed – is now fully exposed." € Have a read through Friedemann Wachsmut’s article. It’s geared towards narrow-gauge film, but it’s identical for 35mm or roll film. € http://www.filmkorn.org/selbstentwicklung-tipps-aus-der-praxis/ € € Rene

KlausWehner

I have put together this new chemical kit for reverse development so that it is safe, simple and easy to use. I have now received quite a bit of feedback from users. I have analysed this feedback and tried to implement suggestions for improvement straight away. € My chemical formula is an in-house development and differs in key respects from the well-known standard formulations. Something that is always particularly important to me is user safety. Typical problematic substances such as potassium dichromate or potassium thiocyanate are not contained in my chemistry. After a short familiarisation period, every user can achieve a consistently high image quality that is significantly superior to that of standard approaches. The chemistry kit consists of 4 liquid concentrates. A second exposure ensures the reversal (this makes economic and ecological sense: it saves on chemicals). The outstanding feature of this new chemistry is undoubtedly the high maximum density that can be achieved with it. (A high maximum density is a prerequisite for a brilliant projected image and conveys an enhanced impression of sharpness). € I have already presented the chemistry at Photokina 2014 and at the 5th fineartforum in Paderborn. I am happy to answer any questions (though there may be a delay due to my current heavy workload). € Anyone who already has experience with reversal development (preferably with rotary development) and is willing to provide me with a brief report of their experience can obtain a test kit of the chemicals from me. Please send enquiries via private message. However, I would ask for a little patience. € Warm regards from Paderborn Klaus €

haeberlein

I can confirm that. Klaus's formula works well. I've already had a chance to try it out. € Rene

KlausWehner

Thanks, Rene, for the feedback! € So far, I’ve mainly optimised my chemicals for slide film. Narrow-gauge film users have a slightly different focus (I learnt that from Rene). In principle, I’d also like to optimise the chemistry for narrow-gauge film use. However, I don’t know enough about the specific requirements of narrow-gauge film processing. € My chemistry is currently optimised for processing black-and-white slides (preferably in rotary development). Recommended films: Adox CHS 100 II (important: 200 or 400 ASA only) Adox Silvermax (200 ASA) and Agfa Scala (200 ASA) I just wanted to add that briefly. € Best regards Klaus

GeorgSch

Hello Mr Wehner, Where can I buy your chemicals? Kind regards, Georg

KlausWehner

The software is currently only available from me. It’s still a trial version. You can contact me at: [url=mailto:klaus.wehner@web.de]klaus.wehner@web.de[/url] € Warm regards from Paderborn Klaus €

AchimBauer

Hi Ulf – Benno, ? Unfortunately, I’ve had to spend the day gathering some tedious paperwork today; it’s got absolutely nothing to do with photography, nor with my hobby. To this end, I’ve fired up my old, battered internet computer to search for some data, and whilst I’m rummaging through ‘My Documents’, I open an unnamed PDF. Is this the document I’m looking for? No, it’s a guide from Ilford on the reversal processing of films. For the initial development, they use Bromophen 1+1 or PQ Universal 1+5 with 8 to 12 g of sodium thiosulphate. Bleaching is done with potassium permanganate and sulphuric acid, and development takes place in Bromophen 2. Just have a look on the Ilford website. I’ll keep looking for my documents ? Regards, Achim

jochen53

Hello Achim, The formula uses sodium thiosulphate instead of potassium thiocyanate, as it is easier to obtain and cheaper. The bleaching agent is the typical potassium permanganate/sulphuric acid dichromate substitute, which often causes problems and has a short shelf life. It lacks the modern insights needed to stabilise the permanganate bath.

KlausWehner

Ultimately, all reversal formulas are similar, with only minor variations. Why is this the case? It becomes clear here in the forum too: everyone adopts a tried-and-tested formula and then passes it on exactly as it is. € When I first got to grips with the subject about 25 years ago, I took a different approach. My starting point was that I was dissatisfied with all black-and-white slides. I then considered what characteristics an ideal black-and-white slide should possess. Based on these criteria, I developed my very own process: the ‘Wehner reversal process’ € So I approached the problem from the end result, and I believe that is the key difference. The superior quality of the slides is visible, measurable and is no longer seriously questioned by anyone today. € The new chemistry kit is based on my Wehner reversal process. It too delivers significantly better quality than standard processes, provided you follow the instructions. € Warm regards from Paderborn Klaus

mattes

I’m glad that someone has gone to the trouble of developing a black-and-white reversal kit. I started out with the Tetenal reversal kit. When that was no longer available, I worked with the Ilford formula and, of course, with Fomachemie as well. I’ve experienced everything from total failure to top-notch results. The bleaching and fixing baths were the critical factors for me. The film emulsions are not suitable for prolonged contact with water; I once left a film in a water bath after processing, and after just under two hours, the emulsion had transferred. You should keep the times short and the temperatures low. Films such as Skala and R100 are designed for this process, whilst traffic surveillance films can tolerate high temperatures. With standard black-and-white negative films, you have to be prepared for anything.

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