Rodinal confusion

[Grandpa Ron]

In a previous post I was looking for a mix as needed developer and Adox Rodinal was suggested.

I have been doing a bit of tail chasing trying to determine the proper Rodinal mixture for 4x5 film.

• My tank holds 55 oz. or 1627 ml and will process 1 to 12 4x5 sheets. I typically process 4 to 6 sheet in a session.
• I believe I read that for an 8x4 sheet, a minimum of 5ml of Rodinal is recommended. This would be 4 sheets of my 4x5 film. However, I do not know if this is for tray or tank development. I am looking for tank information.
• If I were to do 12 sheets of 4x5 that would require 15 ml developer but only produce 750 ml of a 50:1 mixture which is less than 1/2 what I need in my tank.
• So, to maintain a 50:1 ratio I would need 32.5 ml of developer. Or, 65 ml at 25:1 in my 1627 ml tank.

If I am correct, I need to maintain the 50:1 or 25:1 developer mixture, regardless of any minimum developer data. Is this correct?

 

[Tim Tucker 2]

Yes you need to maintain the dilution, i.e. mix enough to fill the tank at say 50:1. It is the surface area/dilution that's important and this dictates the minimum quantity of developer otherwise it will exhaust before the sheet is developed.

 

[Grandpa Ron]

Thanks Tim,

This 4x5 format has been a steep learning curve, but it is so intriguing you just cannot stop.

 

[ac12]

It has been way too many years, but as I recall, agitation affects the film contrast with Rodinal.
I "think" Rodinal was meant to be used with minimal agitation, to bring out the shadows.
Agitate too much and it becomes a high contrast developer.

Hopefully, someone with more recent Rodinal experience will speak up.