Rodinal fine grain mod

[baachitraka]

If fine grain then why Rodinal? But then, what is fine grain?

 

[Leigh B]

Rodinal yields very high acutance, which complements fine grain quite nicely.

I shoot no film faster than ASA 100.

- Leigh

 

[Athiril]

Adding potassium thiocyanate to Xtol produced dichroic fog with some films, this wasn't the case when I used it with Rodinal, since it had no solvent ability on its own.

The grain from about 1.4g/L of potassium thiocyanate to working solution (whether you used 1:25, 1:50, or 1:100) produced grain about equal to Xtol.

There is a huge difference in the grain produced between Rodinal and Xtol, even on the mentioned films such as Delta 100 and T-max 100 etc, so Rodinal doesn't produce exceptionally fine grain on Delta 100, Xtol does, Rodinal does not. Delta 100 is already fine to start with so of course it'll be finer than conventional films.

The one film I found with the smallest change in grain between solvent and non-solvent developer was Rollei Retro 80s. Probably because its so ridiculously fine to begin with.

Potassium Thiocyanate also greatly sped up developing speed on Delta 100 I found. At least in 1:25.


There was no drop in resolving power/sharpness with this method. In fact, adding potassium iodide 5mg per litre of working developer improved resolving power on most films, Delta and T-Max slightly, FP4+ significantly. The amount for Delta and T-Max may be lower or higher for better results, 5mg seems right for FP4+.

 

[Leigh B]

Thanks very much, Athiril.

I appreciate the info.

I don't shoot any T-grain films from any manufacturer, but I do shoot FP4+.

Is the iodide in addition to the thiocyanate or instead of it.

- Leigh

 

[piu58]

If Rodinal is used adequate, the grain is not coarse. But it is SHARP and can be detected more easily.

 

[Leigh B]

If Rodinal is used adequate, the grain is not coarse. But it is SHARP and can be detected more easily.

True.

That's the 'acutance' that I referenced earlier.

- Leigh

 

[Athiril]

In my tests, Rodinal was never sharper than Xtol (replenished), it was generally the same, unless stand developing, than it was worse. Xtol was just clearer at the same sharpness at fine detail (due to finer grain).

Leigh, in addition. The potassium thiocyanate only affected grain, and in some cases increased developing speed. The iodide increased resolving power in my tests on most films. Neither seems to interfere with the other used in combination. The iodide trick also works when added by itself to solvent developers like Xtol.

 

[baachitraka]

Is pot. thiocyanate softening the emulsion?

I have used Ammonium thiocyanate to stabilize the lumen prints but they were not good for emulsion.

 

[Leigh B]

Neither seems to interfere with the other used in combination.

Thanks for the clarification.

Sounds interesting.

- Leigh

 

[Gerald C Koch]

Is pot. thiocyanate softening the emulsion?

I have used Ammonium thiocyanate to stabilize the lumen prints but they were not good for emulsion.

Depends on the amount used. When used in the concentrations for reversal processing (2 to 4 g/l) I have never experienced any difficulty.

 

[baachitraka]

Depends on the amount used. When used in the concentrations for reversal processing (2 to 4 g/l) I have never experienced any difficulty.

Now I wonder whether softening the emulsion have any influence on grain or any other properties in the matter?

 

[Gerald C Koch]

Please everyone forget the erroneous notion of "grain clumping." It just doesn't happen. The halide crystals in an emulsion are firmly fixed in position.

 

[Christiaan Phleger]

I vote to make certain photographic phrases be listed in APUG top hits as "FALSE/FAIL/". Too much effort is lost correcting bad information moving forward in regards to photography.

Grain Clumping is certainly at the top of my list for phrases.

 

[Gerald C Koch]

I vote to make certain photographic phrases be listed in APUG top hits as "FALSE/FAIL/". Too much effort is lost correcting bad information moving forward in regards to photography.

Grain Clumping is certainly at the top of my list for phrases.

+10,000

 

[Andrew O'Neill]

Not really on topic, but I sometimes would put 5ml of Rodinal with 500ml of Xtol 1+1. It really gave HP5 a kick in the pants!
Back on topic, I'll have to give potassium thiocyanate in Rodinal (actually a Rodinal wannabee, Blazinal) a shot since I have it in my d room.