Adox CMS 20 Slides, what bleaching chem ???

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Originally Posted by Malanov

Hi,
I'm new here. Could you please let me know if you have any good results with Adox CMS 20 II?

I developed a couple of slides in Ilford PQ Universal 1+5 with 8g hypo 1 min 45 sec as longer development removes emulsion. Anyhow, a colour of developer changed to slightly black, which was not a good sign as it should be slightly green, and it turned out that emulsion started removing (even at 1 min. 45 sec) but insignificantly. For bleaching (around 45 sec) I use potassium bichromate 10 g with sulfuric acid (conc.) 10 ml per 1l of water.

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CMS20 runs well (if rather contrastily) in the old Agfa Scala process - the first developer of which seems to be disclosed here , specifically the following:

4.5 g hydroquinone
11.0 g Potassium Sulphite
41.7 g Potassium Carbonate
1.5 g Sodium Carbonate
5.5 g Potassium Hydroxide
2.0 g Nitrilotriacetic acid
1.6 g Potassium Bromide
67 mg Benztriazole
3.8 g. N-methyl-4-aminophenyl-hydrogen Sulphate (metol)
0.4 ml hydroxyethane-diphosphonic acid
1.2 g Polyethylene Glycol, molecular weight 1500
2.0 g Sulphuric acid
made up with water; pH 10.2

There are several interesting aspects, but the main thing to note (which may be important for the successful handling of CMS 20) is that there is no grain solvent, rather there is a development accelerator (the PEG-1500) & that it is an MQ developer (in this form). The problem with a highly monodisperse film like CMS 20 (that may actually have more in common with a paper emulsion than a film emulsion - ie chloride/ high chloride content) is that a solvent developer will effectively act like a weak monobath at a certain point, slowing/ stopping development rather than allowing all the silver to be developed. PQ Universal might make a good starting point, though you may need to experiment with various molecular weights of PEG (not Polypropylene Glycol that some use to mix Pyrocat in) to maximise the effect.

Thank you. This is an impressive answer. I'm not a qualified chemist, rather an amateur. As I understand the major failure of my approach is about adding hypo/grain solvent and I should rather apply PEG-1500.

Quote:

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Originally Posted by Malanov

Thank you. This is an impressive answer. I'm not a qualified chemist, rather an amateur. As I understand the major failure of my approach is about adding hypo/grain solvent and I should rather apply PEG-1500.

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Excessive solvency might be the cause of the problem - or it might not. That CMS 20 runs in Scala, but fails in other reversal systems tends to suggest that a development accelerator, rather than a silver solvent might be the answer. Unfortunately, I can't immediately suggest what the right PEG (could be as low a molecular weight as 400, or as high as 4000) might be for PQ Universal - you will need to experiment until you get acceptable reversal & highlights. If you try the above formula & use de-ionised/ distilled water, I think you could probably get away without the nitriloacetic acid and the hydroxyethane-diphosphonic acid. I am planning to look into reversing sheet CMS 20 for darkroom purposes later this year (single step separation negatives from colour negatives), so I intend to look into using PQ Universal as a first developer & the amount of PEG that might need to be added.

Quote:

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Originally Posted by Malanov

Hi,
I'm new here. Could you please let me know if you have any good results with Adox CMS 20 II?

I developed a couple of slides in Ilford PQ Universal 1+5 with 8g hypo 1 min 45 sec as longer development removes emulsion. Anyhow, a colour of developer changed to slightly black, which was not a good sign as it should be slightly green, and it turned out that emulsion started removing (even at 1 min. 45 sec) but insignificantly. For bleaching (around 45 sec) I use potassium bichromate 10 g with sulfuric acid (conc.) 10 ml per 1l of water.

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I've dabbled with reversal processing of Adox CMS 20ii. I used home brew ID-62 as the first developer without any halide solvent and I got very decent results. I used copper sulphate + sodium chloride bleach. Others have had problems with this film when using stronger bleaches like dichromate and permanganate.

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Originally Posted by interneg

CMS20 runs well (if rather contrastily) in the old Agfa Scala process - the first developer of which seems to be disclosed here , specifically the following:

4.5 g hydroquinone
11.0 g Potassium Sulphite
41.7 g Potassium Carbonate
1.5 g Sodium Carbonate
5.5 g Potassium Hydroxide
2.0 g Nitrilotriacetic acid
1.6 g Potassium Bromide
67 mg Benztriazole
3.8 g. N-methyl-4-aminophenyl-hydrogen Sulphate (metol)
0.4 ml hydroxyethane-diphosphonic acid
1.2 g Polyethylene Glycol, molecular weight 1500
2.0 g Sulphuric acid
made up with water; pH 10.2

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After being recommended to use this developer in reversal processing on photrio, I've used it as first developer for some B&W films (but not on Adox CMS 20ii or the original Scala reversal film). It works fine but is no magic bullet. Other well-known first developers give similar results.

I'll try on Monday/Tuesday PQ Universal with PEG-1500 and the same bleaching as a starting point. I wonder on timing since 1min 45 sec with hypo was too much.

Even 7 min 30 sec is not enough. A picture is visible but very dark.

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Originally Posted by Malanov

Even 7 min 30 sec is not enough. A picture is visible but very dark.

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Could be due to underexposure. What is your exposure index for this film? It won't give the box speed of 20 in anything other than Adotec developer. I rated the film at 6 and got pretty decent slides.

20 ISO, it can be underexposure, yet, the attempt with hypo produced a proper exposure. Maybe I should double PEG or add a bit of hypo, say 0.5g per 1 liter. What do you think?

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Originally Posted by Malanov

20 ISO, it can be underexposure, yet, the attempt with hypo produced a proper exposure. Maybe I should double PEG or add a bit of hypo, say 0.5g per 1 liter. What do you think?

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PEG isn't a magic bullet IMO. Increasing the proportion of an ingredient beyond what is recommended can potentially cause unintended effects. You can try adding hypo, but it may reduce density in shadows and reduce overall contrast. The last thing you want is a slide that has clear highlights but low contrast. Why not give additional exposure and see what you get?