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Pere Casals
20-Jul-2016, 07:54
I tried several ways to reverse ADOX CMS 20, I failed to obtain good results.


Well, I obtained interesting burnt lomographic results:

https://www.flickr.com/photos/125592977@N05/22569910808/in/dateposted-public/


But I'd like to obtain a quality result like if it was from one of those good labs:

http://www.adox.de/Photo/adox-films-2/cms-20-ii-adotech-ii/


I've the problem with bleaching, both Permanganate and Dichromate remove too much Silver Halide (that should stay...), I've tried different times and concentrations...

So... what bleach agent can be used ?

Thanks in advance !

interneg
21-Jul-2016, 15:15
It's not your bleach that's the problem, it's your developer that you need to change. The Photostudio13 process is the standard Agfa Scala one, & that will almost certainly use a fairly powerful first developer in the D-19/ PQ Universal sort of direction. I'd strongly suggest getting a roll of CMS20 processed by them, as it'll give you a useful reference point. I've just received a roll of CMS20 processed by PS13 & can post an example if that would be of any use. It is an extremely contrasty film, even after reversal processing, but a surprising amount can be extracted if you know what you are doing with a Hasselblad/ Imacon/ high-end flatbed/ drum scanner.

Pere Casals
21-Jul-2016, 18:58
Thanks for the The Photostudio13 information... I'll consider to have a benchmark, anyway I'm interested in developing it myself.

I also tried with PQ Universal, it is in the reversal recipe from Ilford.

As first developer I used Adotech II, consider that CMS is microfilm and it renders extreme contrast as it is monodisperse, so all grains are of similar size so there is no natural tone gradation, a low contrast developer is needed !

After stop bath I open lights (as it can be done and I do with any reversal) and see metallic silver and silver halide, it is correct because if I fix it I obtain a normal negative, but if I apply bleach (permanganate or dichromate) metallic silver goes away but halide also does, when it should stay.

I'd like to see that example please, if possible, to know what results can be obtained !!

Thanks in advance

tgtaylor
22-Jul-2016, 08:42
http://www.largeformatphotography.info/forum/showthread.php?125393-Reversal-Processing-with-D-11

Thomas

Pere Casals
22-Jul-2016, 10:13
http://www.largeformatphotography.info/forum/showthread.php?125393-Reversal-Processing-with-D-11

Thomas

Hello Tomas,

thanks for that link, there is interesting information in that thread that I'll use for other films, but still no solution for an ADOX CMS 20 suitable bleach bath that do not wash out halide it should stay...

Pere

tgtaylor
22-Jul-2016, 11:51
For the bleach, I used the formula for DW-1 given at page 320 of the Darkroom Cookbook, 3d edition.

Thomas

interneg
22-Jul-2016, 13:11
Thanks for the The Photostudio13 information... I'll consider to have a benchmark, anyway I'm interested in developing it myself.

I also tried with PQ Universal, it is in the reversal recipe from Ilford.

As first developer I used Adotech II, consider that CMS is microfilm and it renders extreme contrast as it is monodisperse, so all grains are of similar size so there is no natural tone gradation, a low contrast developer is needed !

After stop bath I open lights (as it can be done and I do with any reversal) and see metallic silver and silver halide, it is correct because if I fix it I obtain a normal negative, but if I apply bleach (permanganate or dichromate) metallic silver goes away but halide also does, when it should stay.

I'd like to see that example please, if possible, to know what results can be obtained !!

Thanks in advance

153173

This is a very quickly prepared .jpg from a Hasselblad/ Imacon scan I did yesterday. I opened the shadows in the scan, but otherwise it was straightforward to get a good scan. I've not removed any dust or sharpened it or done any other work other than resizing for web. I'm aware that it'll look pretty poor as an attachment - let me know if you want me to send you a higher res file.

I'd like to re-iterate that the PS13 Scala process is, apart from time in the 1st developer, standardised across all films. Thus Delta 400 gets 10 mins in 1st dev, and CMS gets 3 mins. They are able to get full film speed out out of Delta 400 & TMY II, and according to their PDF, will push TMY to 800. This suggests a pretty punchy low fog first developer with a silver solvent (probably a thiocyanate or similar) added to ensure ultra clean highlights.

The 120 Delta 100 & 400 I had developed at the same time turned out very nicely, as did the Silvermax I had processed on a previous occasion. They all have a superb Dmax & clean, crisp highlights.

The key thing to bear in mind is that you need a contrastier, cleaner working developer for reversal than you'd use for processing to a negative - Adotech is not the right choice here. Your problems are not down to the bleaching but rather an inadequate developing stage - poor Dmax, possible dichroic fog amongst other faults.

Pere Casals
22-Jul-2016, 17:32
153173

This is a very quickly prepared

Many thanks for the information, it is of very high interest to me, I'd enjoy viewing it projected !





Your problems are not down to the bleaching but rather an inadequate developing stage


No... I'm pretty sure of it... nor Permanganate or Dichromate worked to me with CMS 20. To be sure I exposed 2 frames in a contact print frame, half of each frame was overexposed, and half of each was not exposed. Then I developed, so I had frames that half was pure metallic silver and the other half was pure halide.

One of them was fixed lights open and it resulted as expected, one half black and the other half transparent. The other one was bleached, also lights open, and halide was being washed out at near the same speed than metallic silver, when halide had to stay.

True that the developing has to to be adjusted, but bleach washed that delicate and monodisperse small halide chrystals... and also I tried different dilutions of bleach bath...

Pere Casals
22-Jul-2016, 17:37
Yes... I tried DW-1, Dichromate, and it did not work, it removes CMS hallide at near same speed than removes metallic silver.

Those grains are very small, even fixer can damage them after 30 seconds, CMS 20 datasheet says...

interneg
23-Jul-2016, 02:04
No... I'm pretty sure of it... nor Permanganate or Dichromate worked to me with CMS 20. To be sure I exposed 2 frames in a contact print frame, half of each frame was overexposed, and half of each was not exposed. Then I developed, so I had frames that half was pure metallic silver and the other half was pure halide.

One of them was fixed lights open and it resulted as expected, one half black and the other half transparent. The other one was bleached, also lights open, and halide was being washed out at near the same speed than metallic silver, when halide had to stay.

True that the developing has to to be adjusted, but bleach washed that delicate and monodisperse small halide chrystals... and also I tried different dilutions of bleach bath...

Whether the grains are mono- or polydisperse is not really of concern here, what is of concern is whether they were fully developed or not. If they did not fully develop, they will get bleached out - this is what you are experiencing. A developer with a high reduction potential and a silver solvent (a thiocyanate or di-thia-octan-diol) is where you should be starting from. The first developer from a 6-bath E6 may be a place to start from (I would not be surprised if the Scala process has remarkable similarities to E6, barring colour developer and final bleaching stages).

You should also look into what Ron Mowrey (Photo Engineer) says in these posts about reversal processing: http://www.apug.org/forum/index.php?threads/theory-of-silver-halide-solvent-in-b-w-reversal.49899/#post-724203 and http://www.apug.org/forum/index.php?threads/theory-of-silver-halide-solvent-in-b-w-reversal.49899/#post-724205

LabRat
23-Jul-2016, 04:26
Thanks for the The Photostudio13 information... I'll consider to have a benchmark, anyway I'm interested in developing it myself.

I also tried with PQ Universal, it is in the reversal recipe from Ilford.

As first developer I used Adotech II, consider that CMS is microfilm and it renders extreme contrast as it is monodisperse, so all grains are of similar size so there is no natural tone gradation, a low contrast developer is needed !

After stop bath I open lights (as it can be done and I do with any reversal) and see metallic silver and silver halide, it is correct because if I fix it I obtain a normal negative, but if I apply bleach (permanganate or dichromate) metallic silver goes away but halide also does, when it should stay.

I'd like to see that example please, if possible, to know what results can be obtained !!

Thanks in advance

Read Thomas' link carefully with the discussion we had about reversal processing...

I'm wondering if the emulsion of CMS might be too thin for reversal processing??? (Old school thicker emulsion films tend to work better...)

Steve K

Pere Casals
23-Jul-2016, 05:45
The first developer from a 6-bath E6 .


Perhaps, I ask... can the first developer of a 3 bath E-6 kit also work?

Tetenal Colortec E-6: "The film reversal takes place during the colour development. Bleaching and fixing are in a combined bleach fixer",

So first developer bath of the 6-Bath may be equivalent to the 3 bath kit one, as both are only silver developers... (I've Colortec in the shelf...)




You should also look into what Ron Mowrey (Photo Engineer) says in these posts about reversal processing

Thanks for the links, good information, I'll read it twice.

Pere Casals
23-Jul-2016, 05:57
I'm wondering if the emulsion of CMS might be too thin for reversal processing??? (Old school thicker emulsion films tend to work better...)

Steve K


Yes, it's very thin, anyway it is done by a copule of labs with "scala process" with impressive results.

CMS grains are very small, ISO 3 or 6 tipical, (even it is shot at ISO 12 or 20) so they have a large surface vs mass relationship, any harm a bleach bath do to halide chrystals if multiplied by a big factor when reversing CMS 20 microfilm material, compared to common pictorial films... what can be tolerated for other films destroys CMS 20, even fixing more than 30 seconds may destroy highlights.


I'll read again Thomas' link, thanx

Regards
Pere

Donald Qualls
23-Jul-2016, 06:34
It might be worth looking back to reversal processes intended for Tech Pan; there are similarities between that film and the document films that are the basis of CMS 20, including the use of very low contrast process for negatives. Kodak used to sell a reversal kit intended specifically for Tech Pan, but there were also a number of "off the shelf" processes, including use of self-fogging second developers for either black or sepia image (the latter was approximately use sepia toner). Key in all of these was the first developer, but I don't recall details of the process (it's been close to thirty years since I read up on it).

Pere Casals
23-Jul-2016, 09:13
It might be worth looking back to reversal processes intended for Tech Pan; there are similarities between that film and the document films that are the basis of CMS 20, including the use of very low contrast process for negatives. Kodak used to sell a reversal kit intended specifically for Tech Pan, but there were also a number of "off the shelf" processes, including use of self-fogging second developers for either black or sepia image (the latter was approximately use sepia toner). Key in all of these was the first developer, but I don't recall details of the process (it's been close to thirty years since I read up on it).

Thanks for the clue Donald,

I've searched and I found a Tech Pan process: http://www.tech-diy.com/reversal_formulas.htm

I found this formula for the Dichromate bleach bath:

Bleach: Add to 1 litre water 9.5 g Potassium Dichromate and 66g Sodium Bisulfate and stir until dissolved.


This is different from the general DW-1 of the Cookbook I was using

DW-1
Bleach Bath
(David Wood)
Potassium bichromate (Dichromate), anhydrous, 6.0 g
Water to make 1.0 liter
Sulfuric acid, concentrate, 12.0 ml


I'll try it. Thanks again.


Regards,

Pere Casals

Domingo A. Siliceo
25-Jul-2016, 00:35
Pere, if you don't have yet enough ideas, take a look at the Ian Grant's post in APUG (http://www.apug.org/forum/index.php?threads/kodak-b-w-reversal-processing-formulae.40039/) for some more thoughts.

Pere Casals
25-Jul-2016, 02:56
Pere, if you don't have yet enough ideas, take a look at the Ian Grant's post in APUG (http://www.apug.org/forum/index.php?threads/kodak-b-w-reversal-processing-formulae.40039/) for some more thoughts.

Many thanks, following your link I found this interesting video:

https://www.youtube.com/watch?v=OvGCaZy_kUY

interneg
25-Jul-2016, 03:11
Pere, if you don't have yet enough ideas, take a look at the Ian Grant's post in APUG (http://www.apug.org/forum/index.php?threads/kodak-b-w-reversal-processing-formulae.40039/) for some more thoughts.

I'd also add a couple of other things I've just remembered - it's a bad idea to use a thiocyanate containing developer with a permanganate bleach (risk of liberating cyanide) - thus why Kodak changed D94 (which contains thiocyanate) to D94a (which uses D-TOD) when they went from R9 (dichromate) to R10 (permanganate) bleach. You should read http://www.apug.org/forum/index.php?threads/kodak-d94-incompatible-with-r10-bleach.65708/ as it goes over the potential dangers of thiocyanates & permanganates mixing.

Kodak do offer a Motion Picture BW reversal development kit -http://motion.kodak.com/US/en/motion/Products/Lab_And_Post_Production/Chemicals/Black_and_White_Reversal_Kit_Chemicals/default.htm with the above developers & bleaches, however it is designed to make 15 US gallons.

http://www.apug.org/forum/index.php?threads/dtod-in-kodak-d94a-for-motion-picture-film.5653/ has the formula for D94a

Pere Casals
26-Jul-2016, 10:46
I'd also add a couple of other things I've just remembered - it's a bad idea to use a thiocyanate containing developer with a permanganate bleach (risk of liberating cyanide) - thus why Kodak changed D94 (which contains thiocyanate) to D94a (which uses D-TOD) when they went from R9 (dichromate) to R10 (permanganate) bleach. You should read http://www.apug.org/forum/index.php?threads/kodak-d94-incompatible-with-r10-bleach.65708/ as it goes over the potential dangers of thiocyanates & permanganates mixing.

Kodak do offer a Motion Picture BW reversal development kit -http://motion.kodak.com/US/en/motion/Products/Lab_And_Post_Production/Chemicals/Black_and_White_Reversal_Kit_Chemicals/default.htm with the above developers & bleaches, however it is designed to make 15 US gallons.

http://www.apug.org/forum/index.php?threads/dtod-in-kodak-d94a-for-motion-picture-film.5653/ has the formula for D94a

Many thanks for the links, I'm to use dichromate as bleach, taking necessary care (and end mixing used developer to reduce chrome later...) instead thiocyanate I'm to use tiosulfate at first.

Thanks to cinematographers we still have this asset as a benchmark, but the 15 gallons...

I'm to read those links, thanks again