Adox CMS 20 Slides, what bleaching chem ???

[Pere Casals]

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/125592...posted-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-...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]

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]

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

[interneg]

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

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]

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...

[interneg]

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?...9/#post-724203 and http://www.apug.org/forum/index.php?...9/#post-724205

[Pere Casals]

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.

[LabRat]

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]

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

[tgtaylor]

http://www.largeformatphotography.in...sing-with-D-11

Thomas