Wanting to try reversal processing but also not die

[138S]

I wouldn't expect C-41 bleach to work, unless via forming silver chloride and then using an ammonia bath to remove only the chloride.

What I'd be tempted to try with CMS-20 or other document films is apply a halide-reactive toner (like the sepia/sulfide toner that was used in Kodak's T-Max Reversal Kit) to allow developing the positive image before bleaching. Then you can use a C-41 blix to remove the silver developed in the first dev. This probably wouldn't work with conventional films; you'd have too much fog in the highlights where silver that didn't develop took the toner, but CMS-20 shouldn't have much of that problem due to the monodispersed thin emulsion (if I've understood correctly why that makes the film high contrast by nature).

Donald, cooper path it's known to work with CMS 20.

 

[138S]

Only in the most generic terms could you regard a paper developer as a suitable reversal first developer & even then it's something closer to the 'universal' type of developer that you want. What's more important is how it is engineered to perform in the specific situation.

David Wood (aganist silver solvent tradition) has been recommending bare (high contrast) Kodak D-11 for the first developer, a bit conceptually in the way of the Scala process you pointed, being paper D-72 (Dektol) a good choice for the second round. I agree with this: Energy instead silver solvent

He also says: "The SCALA process uses a LIGHT-reversal procedure. We feel this is the wrong approach to reversing B&W film." In don't agree with that, here I'd say YMMV.

 

[Raghu Kuvempunagar]

David Wood (aganist silver solvent tradition) has been recommending bare (high contrast) Kodak D-11 for the first developer, a bit conceptually in the way of the Scala process you pointed, being paper D-72 (Dektol) a good choice for the second round. I agree with this: Energy instead silver solvent

Isn't this a false dichotomy? First developers have always been high energy (paper strength) developers but some of them have appropriate amount of silver solvent. Is there a first developer in the literature that is low energy and uses silver solvent? How would such a developer build the contrast needed for slides?

BTW @Ian Grant has published several reversal formulas on his website: http://www.lostlabours.co.uk/photography/formulae/formulae.htm. All of them appear to be high energy developers.

 

[Raghu Kuvempunagar]

Of course, but it's surprising that a manufacturer of the ilford's size says that about his film, instead showing a suitable recipe

Peter Carter, from whose flickr tutorial I learned my first lessons of reversal processing, says this about HP5:

I'll second that. HP5 works well, just leave out the solvent. I consider it a film that works well naturally.

I guess Ilford didn't really experiment with low amounts of or no thiosulphate for HP5.

 

[Ian Grant]

BTW @Ian Grant has published several reversal formulas on his website: http://www.lostlabours.co.uk/photography/formulae/formulae.htm. All of them appear to be high energy developers.

Most are also in the Resources section on this website as well.

Ian

 

[138S]

Isn't this a false dichotomy? First developers have always been high energy (paper strength) developers but some of them have appropriate amount of silver solvent. Is there a first developer in the literature that is low energy and uses silver solvent? How would such a developer build the contrast needed for slides?

IMO there is a dichotomy, to clear highlights from 1st developer action we may enhance more the energy or more the solvent, we have both effects, but we may boost one or the other.

 

[Lachlan Young]

David Wood (aganist silver solvent tradition) has been recommending bare (high contrast) Kodak D-11 for the first developer, a bit conceptually in the way of the Scala process you pointed, being paper D-72 (Dektol) a good choice for the second round. I agree with this: Energy instead silver solvent

He also says: "The SCALA process uses a LIGHT-reversal procedure. We feel this is the wrong approach to reversing B&W film." In don't agree with that, here I'd say YMMV.

Except that D-11 has much higher sulphite levels & it has a drastically different ratio of M:Q compared to the disclosed Agfa first developer. D-11 will almost definitely be foggier than the Agfa first developer. The Agfa developer is considerably more sophisticated - the PEG likely slightly swells the gelatin as well as accelerating the development, enabling much better penetration of the developer components into the totality of the emulsion(s), which then develop at a more simultaneous rate (likely from knowledge from colour processing research- which seems to have been the background of at least one of the Agfa patent holders). A more polydisperse, less tightly packed emulsion with less complex layer structures may well develop enough of the silver without needing accelerators or solvents (though who knows, maybe HP5+ has polymeric extenders in the emulsion which have effects in line with adding PEG to the developer).

Mr Wood sometimes lets his opinions get in the way of the very high quality imaging science work done by Agfa, Kodak etc on reversal processing. Light reversal is actually part of testing/ troubleshooting the reversal step in E-6. Either light or chemical reversal will work equally well, if used correctly. The other thing which immediately colours my opinion of DR5 is Wood's lack of disclaimer about the effects of grey triacetate base film on the highlights - Photo Studio 13 in their Scala process document strongly recommend that you should only use clear base film for Scala reversal processing - which is why 120 & sheet TMax 400, Delta 100/ 400 etc are recommended, but the 35mm equivalents aren't.

 

[Ian Grant]

It's a few years now since I did some work for a lab in London (UK) planning to introduce a B&W Reversal service, unfortunatel it's still commercial and as they paid for it legally and morally I can't publish the final formula at the moment. When I get time I'll revisit my notes, this lock-down means I have gardening and housework priorities to keep the other half happy

Around that time dr5 moved location abd Dave Wood had issues, due to a change in water supply, he turned to Ron Mowrey (PE) for help and I rember Ron and I discussing it in a telephone call, Ron found some aspects of the dr5 process rather oddly backward, ut it's what works that counts.

Ian

 

[138S]

, Ron found some aspects of the dr5 process rather oddly backward, ut it's what works that counts.

I guess that in BW reversal we have several control factors and YMMV. There are several ways to do the same...

But also I guess it's difficult to beat what D. Wood does after fighting a 3 decades war. It's not only the development itself but also the toning...

He says that with TXP dr5 reaches 4.70 d-max... if this is true...

Light reversal

Well... with a controlled light reversal we are able to not fog all the halide the bleaching left. We have that "unused silver"...

If we don't fog that silver then second development won't develop it in the highlights, but we may develop it in the shadows via infection... extending dynamic range for the the projection, this is my guess...

 

[Anon Ymous]

@138S Suppose that you actually get a density of 4,7, or whatever ridiculously high value. Is it of much use? Do you believe that you're going to find much detail that can be spotted by a naked eye in that region? With what kind of projector? Consider that a typical E6 slide has a Dmax of about 3,5 and it already is plenty high. Meanwhile, clean highlights are much more important and that's what makes clear base films so nice to project. Rollei Retro 80S looks spectacular when reversal processed.

 

[mohmad khatab]

It's a few years now since I did some work for a lab in London (UK) planning to introduce a B&W Reversal service, unfortunatel it's still commercial and as they paid for it legally and morally I can't publish the final formula at the moment. When I get time I'll revisit my notes, this lock-down means I have gardening and housework priorities to keep the other half happy

Around that time dr5 moved location abd Dave Wood had issues, due to a change in water supply, he turned to Ron Mowrey (PE) for help and I rember Ron and I discussing it in a telephone call, Ron found some aspects of the dr5 process rather oddly backward, ut it's what works that counts.

Ian

Hi teacher
God bless you .
Gardening is a very great thing. I agree with you. It is our Lord more beautiful than photography, especially in the spring. The time for flowers to open.
- Assuming you brought a large format camera.
- Assuming that you photographed the most beautiful flowers of your garden using an x-ray film measuring (10x12), which is somewhat close to (4x5) inches,
What would you do if you wanted to convert this sheet into a reverse positive?
- This idea came to my mind during dinner, and it is known that the reader of the X-ray film is blue.
How can we relieve that cyanosis?
A X-ray film, he mostly has a double-sided emulsion, how can this be handled, will it be beneficial or harmful?

 

[Lachlan Young]

Meanwhile, clean highlights are much more important and that's what makes clear base films so nice to project. Rollei Retro 80S looks spectacular when reversal processed.

Good clean highlights are absolutely essential to making a transparency that looks 'right'.

Well... with a controlled light reversal we are able to not fog all the halide the bleaching left. We have that "unused silver"...

If we don't fog that silver then second development won't develop it in the highlights, but we may develop it in the shadows via infection... extending dynamic range for the the projection, this is my guess...

You're more likely to get some sort of Sabbattier effect. Why do you think that essentially no reasonably modern BW reversal process that is known to work reliably does anything other than fogging to completion?

 

[mohmad khatab]

Except that D-11 has much higher sulphite levels & it has a drastically different ratio of M:Q compared to the disclosed Agfa first developer. D-11 will almost definitely be foggier than the Agfa first developer. The Agfa developer is considerably more sophisticated - the PEG likely slightly swells the gelatin as well as accelerating the development, enabling much better penetration of the developer components into the totality of the emulsion(s), which then develop at a more simultaneous rate (likely from knowledge from colour processing research- which seems to have been the background of at least one of the Agfa patent holders). A more polydisperse, less tightly packed emulsion with less complex layer structures may well develop enough of the silver without needing accelerators or solvents (though who knows, maybe HP5+ has polymeric extenders in the emulsion which have effects in line with adding PEG to the developer).

Mr Wood sometimes lets his opinions get in the way of the very high quality imaging science work done by Agfa, Kodak etc on reversal processing. Light reversal is actually part of testing/ troubleshooting the reversal step in E-6. Either light or chemical reversal will work equally well, if used correctly. The other thing which immediately colours my opinion of DR5 is Wood's lack of disclaimer about the effects of grey triacetate base film on the highlights - Photo Studio 13 in their Scala process document strongly recommend that you should only use clear base film for Scala reversal processing - which is why 120 & sheet TMax 400, Delta 100/ 400 etc are recommended, but the 35mm equivalents aren't.

+1

 

[Ian Grant]

I guess that in BW reversal we have several control factors and YMMV. There are several ways to do the same...

But also I guess it's difficult to beat what D. Wood does after fighting a 3 decades war. It's not only the development itself but also the toning...

He says that with TXP dr5 reaches 4.70 d-max... if this is true...

There's a lot of controls we no longer use. For instance some reversal processes could vary the 2nd exposure, by varying the time or intensity of the re-exposure you can fine tune the final results. alternately the timing of the 2nd developer could be varied so development wasn't to completion. I should add these were techniques used for machine processing of B&W cine reversal films.

If we go back to E3/4 processing the 2nd (colour) development time had to be adjusted as well as te first for push processing. Most of our B&W reversal processes effectively use a full 2nd exposure and 2nd development to completion. One note is full second exposure is enough to fully fog the remaining silver halide, gross over exposure causes different issues.

Ian

 

[Lachlan Young]

There's a lot of controls we no longer use. For instance some reversal processes could vary the 2nd exposure, by varying the time or intensity of the re-exposure you can fine tune the final results. alternately the timing of the 2nd developer could be varied so development wasn't to completion. I should add these were techniques used for machine processing of B&W cine reversal films.

If we go back to E3/4 processing the 2nd (colour) development time had to be adjusted as well as te first for push processing. Most of our B&W reversal processes effectively use a full 2nd exposure and 2nd development to completion. One note is full second exposure is enough to fully fog the remaining silver halide, gross over exposure causes different issues.

Ian

I suspect that with the variable re-exposure, the window between semi-reversal, just enough to to get reversal, and fogging to completion was pretty narrow - and was probably quite tricky to hit consistently.

Anything involving colour couplers is a somewhat different thing, but I think that people underestimate just how much fundamental research work went into getting from E3/ E4 to E-6 especially in terms of coupler technology & hardening. I do wonder if Agfa was planning to shift away from Fischer couplers earlier than they did, but decided to wait until the new Kodak process (that they will likely have been highly aware of) had hit the market. There's quite a torrent of coating machine patents from Agfa at the time relating to getting slide/ bead coaters to behave like waterfall coaters - trying to catch up with Kodak's 20+ years of established high speed coating technology by the looks of it.

 

[Raghu Kuvempunagar]

some reversal processes could vary the 2nd exposure, by varying the time or intensity of the re-exposure you can fine tune the final results. alternately the timing of the 2nd developer could be varied so development wasn't to completion.

Ian, what is the effect produced by the two controls you described on the final result in b&w reversal?

 

[Raghu Kuvempunagar]

@138S Consider that a typical E6 slide has a Dmax of about 3,5 and it already is plenty high.

https://books.google.co.in/books?id=rN3kOMOPMmEC&pg=PA544&lpg=PA544&#v=onepage&q&f=false

It says though color reversal films can have a maximum density of 3.0-3.5 (dynamic range >1000), in practice the available dynamic range is reduced to 300:1 due to screen flare, ambient light and other factors.

 

[Ian Grant]

Ian, what is the effect produced by the two controls you described on the final result in b&w reversal?

I think they were controls for under exposure which would result in a dense positive, I think I have articles on it in older BJP Almanacs and pre-WWII cine books.

Ian

 

[Eldorado Quibbo]

He says that with TXP dr5 reaches 4.70 d-max... if this is true...

If I remember correctly in Grant & Haist excellent books, on the reversal section, there's written that the human eye cannot discern densities above 2.2 or 2.4.
If it's the case, saying that TXP reaches 4.7 DMax is a marketing hype, achieved almost surely with the use of some intensification.
There was a short video of the Tecnolab d&d machine which Wood still uses nowadays that pictures the display of the machine. There are at least two intensification baths at the end of the process.

 

[Raghu Kuvempunagar]

I think they were controls for under exposure which would result in a dense positive

Ian, were there controls which used a halide solvent in the second developer? Interestingly, PE's recommended workflow for paper reversal has a little bit of thiosulphate in the second developer, but was it also used for film?

 

[Raghu Kuvempunagar]

If I remember correctly in Grant & Haist excellent books, on the reversal section, there's written that the human eye cannot discern densities above 2.2 or 2.4.

Basic Photographic Processes and Materials, page #176:

"Although these films are capable of achieving densities over 3.0, the shadows are best reproduced at densities of 2.7 and less."

Good clean highlights are absolutely essential to making a transparency that looks 'right'.

Same book and same page:
"Experience indicates that the minimum useful point on the film positive curve for good highlight reproduction is approximately 0.3 above the density of base plus fog. If the highlights are produced with a greater density than this, they appear too dark, and if the density is any less, they look washed out."

If this is the consensus scientific opinion, then the useful density range is about 2.3 more or less.

 

[Ian Grant]

Ian, were there controls which used a halide solvent in the second developer? Interestingly, PE's recommended workflow for paper reversal has a little bit of thiosulphate in the second developer, but was it also used for film?

Often for amateur small scale use it's recommended that the first developer is reused as the second developer, this is more about economy and simplicity than anything else.

Back around 1973 I went to a lecture by a Research student at Birmingham School of Photography, he was Reversal processing Ilford films mostly FP4 and Pan F and then making Reversal prints on Ilfobrom, the image quality was superb. Ironically he was part funded by Kodak, at the time Michael Langford was head of the Birmingham School of Photography before he left to set up the Photography department at the Royal College of Art with John Hedgecoe.

Ian

 

[Eldorado Quibbo]

Basic Photographic Processes and Materials, page #176:
"Although these films are capable of achieving densities over 3.0, the shadows are best reproduced at densities of 2.7 and less."

I was referring to Grant & Haist vol.2, pages 316-317:

"High maximum densities are not needed becase, as H. Verkinderen has pointed out, "by normal projection all densities-discrimination for densities exceeding from 2.2 to 2.4 is lost"

 

[Raghu Kuvempunagar]

I was referring to Grant & Haist vol.2, pages 316-317:

"High maximum densities are not needed becase, as H. Verkinderen has pointed out, "by normal projection all densities-discrimination for densities exceeding from 2.2 to 2.4 is lost"

Looks like there's a consensus about the maximum density that's useful for viewing.

https://books.google.co.in/books?id=neD6CAAAQBAJ&pg=PA130&lpg=PA130#v=onepage&q&f=false

"The ability of human eye to discern detail in an image varies markedly with the luminance, and deteriorates rapidly below 10 cd m-2. In practice this means that the maximum film density cannot be higher than 2.5-3 unless special high-intensity illuminators are available for film viewing".

 

[Lachlan Young]

There was a short video of the Tecnolab d&d machine which Wood still uses nowadays that pictures the display of the machine. There are at least two intensification baths at the end of the process.

That's interesting - where was this video posted? I've found some videos of the machine on DR5's Facebook, but it'd be useful to get a handle on what he's doing. Running a couple of rounds of intensification would not surprise me given that it could use dichromate like the bleach bath and reduce the need for having Agfa etc's level of knowledge in the dynamics and behaviour of the first developer. It is striking that the Copex films he claims won't run in his system will run just fine in the official Scala process. Almost as if Agfa knew what they were doing and invented a process that worked with different grain structure approaches...