FP4+ requires less dev time than HP5+

[elerion]

Ilford recommends more developing time for FP4 than for HP5, for most developers. Take Rodinal for instance. 9 vs 6 minutes, 1+25 for their box speeds.

I get the opposite results. FP4 requires less dev time for Rodinal, but also for Caffenol. When I develop both films in the same tank (Rodinal 1+25), FP4 comes out with a higher contrast, and pushed like one stop. Also, Rodinal states a dev time of 8 minutes for both films.

Any experiences which correlate or contradicts these results?

 

[giganova]

I use DD-X 1+4 and at 68F, FP4 requires 10 min and HP5 9 min.

 

[02Pilot]

I use both films, expose at half box speed, and develop in Caffenol C-H(RS). FP4+ takes 12.5 minutes @ 20C, and HP5+ 15 minutes @ 20C.

 

[lawrence]

My times @ 20C are:

• Ilford DD-X 1+4 HP5+ 9:00 and FP4+ 9:30
• D76 stock HP5+ 7:30 and FP4+ 8:30

So from my own experiences FP4+ can need a little bit more time but, of course, things could be different with Rodinal.

 

[elerion]

Thanks guys.
The strange fact is that ilford (which time charts seem accurate according many people) states 6 vs 9 min for FP4/HP5 in Rodinal, while I get almost the exact opposite. I repeated it quite a few times; same results. Too much difference to be a slight inaccuracy.