FP4+ and Fomapan 100 in Rodinal

[tho60]

Dear Buddies,

Ilford FP4+ and Fomapan 100 have about the same speed. However, Ilford FP4+ requires twice developing time in Rodinal than Fomapan 100. E.g. 1:50 dilution, 20 Celsius: Ilford FP4+ 17 minutes, Fomapan 100 9 minutes.

Could you tell me the reason?

Thomas

 

[Trius]

Are you sure of the time for FP4+?

 

[Chriscrawfordphoto]

Different films need different developing times depending on the chemical structure of the film. Just because they're the same speed does not mean they need the same times.

My own tests show that FP-4 should be developed for 13 minutes to get normal contrast in Rodinal 1+50.

 

[tho60]

Are you sure of the time for FP4+?

Fomadon R09 manual gives the following data (20 Celsius, 1:50 dilution):
Fomapan 100 9 min, Ilford Pan F+ 18 min.

 

[Jockos]

Fomadon R09 manual gives the following data (20 Celsius, 1:50 dilution):
Fomapan 100 9 min, Ilford Pan F+ 18 min.

Pan F is not FP4 🙂
http://www.ilfordphoto.com/products/product.asp?n=5

 

[markus_h_photography]

This is quite common. While I don't use Rodinal I use Neofin Blue. I develop Tmax100 for 12mins whereas Fuji Acros 100 needs only 6mins.

It all comes down to how the developer reacts with the film type. If I do Tmax100 and Acros100 in HC110 for instance there's only 1min difference in their times and they are the same speed.

 

[Steve M.]

I would try it at 1:25 to give a little boost to FP4's contrast. If you don't over agitate the grain will not be an issue. That's the only dilution I ever use w/ Rodinal, irregardless of the film format. The grain is beautiful, the negs have a little bite, and the developing times are reasonable.