Developers, potassium/sodium hydroxide, and reversal processing

[YoIaMoNwater]

I've had good results with TMax400 using Rodinal and HC-110. The high pH due to the presence of sodium hydroxide in Rodinal definitely helped the process.

This was also something that was discussed with Lachlan and Raghu, as the high pH allowed swelling of the emulsion for complete development during the first step. I've also tested thiocyanate and have found that it actually lowered Dmax, thus, have excluded from my tests.

 

[pkr1979]

Thanks,

This is interesting… I dont know how relevant it is, but I assume both Rodinal and HC-110 dont use Metol either. Does this mean Metol isnt the best developing agent for reversal (for particular films)?

I dont know if phenidol is better then metol but when I compare results in PQ to D11 (Tmax400), I’ll say that PQ overall produces better results based on better tonality and a larger range. But D11 is much more fine grained and more detailed/sharper (yet flatter). Why?

Is there any way to assume what would happen if I added hydroxide and lowered sulfite levels in D11?

I assume this is Ilford PQ Universal: http://lostlabours.co.uk/photography/formulae/developers/devID62.htm
Considering they are not the same would I get different results basen on if I used the regular or concentrate?

Also, can bromide be used to make any developer warmer: http://lostlabours.co.uk/photography/formulae/developers/dev_cool_wam_tones.htm

Cheers
Peter

 

[pkr1979]

OK, so I figured Id try to mix up the ID20 so it will get the same strength as PQ diluted 1:5. And make som minor adjustments.

This means (g/L):
Metol 1,25 (maybe 1,5)
Sodium Sulphite 21 (probably 20)
Hydroquinone 5
Sodium Carbonate 25
Potassium Bromide 1,7 (maybe 2 instead)

I got potassium carbonate and can use that instead, but I think then the amount should be adjusted to 15?
And add 1,7-2 g sodium hydroxide (same amount as bromide).
And increase the amount of sodium sulphite to something closer to 50 g, as I understand (or misunderstand) that this will give finer grain and more detail.

Now, since my understanding of chemistry and how these things work together isnt that great it would be nice with a heads up if Im about to waste my time and chemistry… more then I already have that is

 

[pkr1979]

I also notice that the modern version of PQ uses less bromide (and therefor less hydroxide is needed?), but Im guessing thats because it uses phenidone instead of metol?

 

[Lachlan Young]

I've also tested thiocyanate and have found that it actually lowered Dmax

The good news is that means the KSCN is not behaving atypically from what is reported in the engineering literature in terms of it causing adjacency/ interlayer adjacency effects (which is effectively development inhibition) - but it also clearly illustrates that assumptions about the use of old recipes don't consider two major changes: firstly, B&W emulsions have changed internally quite a bit since the 1970s - let alone the 1930s; secondly, E-6 process compatible materials are designed to be compatible with the components of the process, not the other way round - which means that you can end up fighting built-in behaviours of modern(-ish) B&W emulsions that are intended to improve overall imaging characteristics when exposed/ processed as negs - and which aren't really engineered with thoughts of reversal process needs in mind.

I dont know how relevant it is, but I assume both Rodinal and HC-110 dont use Metol either. Does this mean Metol isnt the best developing agent for reversal (for particular films)?

I dont know if phenidol is better then metol but when I compare results in PQ to D11 (Tmax400), I’ll say that PQ overall produces better results based on better tonality and a larger range. But D11 is much more fine grained and more detailed/sharper (yet flatter). Why?

Is there any way to assume what would happen if I added hydroxide and lowered sulfite levels in D11?

Unless you know under what P:Q ratios/ pH you won't get development inhibition effects from the Phenidone byproducts, Metol would actually seem a better choice for a B&W reversal first developer as even small amounts of HQ in the developer seems to stop Metol producing adjacency effects via exhaustion.

Realistically you'd need to run a series of developer experiments, firstly with the M:Q ratios of D-11, then D-19b varying the sulphite levels (say 30,60, 90g) and with an aim pH somewhere around 10.0-10.3. Then repeat with Dimezone S substituted for Metol (n.b. the ratios of P:Q in direct substitution of Metol with Dimezone S in D-11 and D-19b comply quite well with optimal published ratios - but not with Phenidone - I suspect you'll come up against inhibition effects more clearly in the ratio in D-11). This might eliminate some variables.

 

[pkr1979]

Thanks @Lachlan Young. As far as I understand, the ratio between metol and hydroquinone is affecting contrast and range? Meaning Id like the M:Q ratio to correspond with the P:Q ratio in PQ Universal. This is why I figured Id go with ID20, as I assumed this would be similar to the P:Q ratio in the modern PQ Universal. I might be completely off here off course.

And then increase sulfite levels - to reduce grain. But I assume this in turn would make it necessary to then again adjust M:Q, or the levels of some other components.

However, what I hear you say is that its easier to continue down the road with D11 and adjust the sulphite levels as this would give better contrast and range, as too much sulphite gives a flat image?… and add hydroxide if necessary to get the right pH?

Also, I dont know what inhibition effects is… but this will not be a problem with metol?

 

[Raghu Kuvempunagar]

A truly practical and painless solution to the woes of reversal processing is to switch to a film that is known to work well. TMax 400 like Acros 100 is rather a difficult film for reversal and the results are not great either.

 

[pkr1979]

A truly practical and painless solution to the woes of reversal processing is to switch to a film that is known to work well. TMax 400 like Acros 100 is rather a difficult film for reversal and the results are not great either.

I find that TMax400 does work well. The results I got with PQ is probably the best results Ive gotten with any film/developer combo. What Im doing now is just to see if I can mix this stuff up myself... and if it can be improved

 

[Lachlan Young]

Thanks @Lachlan Young. As far as I understand, the ratio between metol and hydroquinone is affecting contrast and range? Meaning Id like the M:Q ratio to correspond with the P:Q ratio in PQ Universal. This is why I figured Id go with ID20, as I assumed this would be similar to the P:Q ratio in the modern PQ Universal. I might be completely off here off course.

And then increase sulfite levels - to reduce grain. But I assume this in turn would make it necessary to then again adjust M:Q, or the levels of some other components.

However, what I hear you say is that its easier to continue down the road with D11 and adjust the sulphite levels as this would give better contrast and range, as too much sulphite gives a flat image?… and add hydroxide if necessary to get the right pH?

Also, I dont know what inhibition effects is… but this will not be a problem with metol?

Inhibition effects are essentially micro restraining effects taking place as iodide & bromide are released from the emulsions as they develop - in particular from more solvent developers accessing the emulsions more effectively (or from reaction with phenidone byproducts - or metol exhaustion byproducts, but only in metol only developers) - which contribute significantly to edge sharpness & can be exploited to deliver more controlled highlight density etc. For the purposes of B&W reversal with modern emulsions, their presence seems to be potentially undesirable as they may make it harder to fully develop the emulsions effectively. If you want to work with ID-20, you'll probably want to investigate restrainer levels (the least necessary to prevent general fog without impacting on tonal range), metol levels (possibly raising them) and sulphite levels - then investigating development accelerators too. From recall, I think a pH around 10-10.3 seems to be optimal in terms of sharpness.