Fp4+ in Microphen & Rodinal

[Willie Jan]

Hi,

I made two 4x5" on fp4+.
Shot was taken at 125 asa.
What i wanted to see is that the microphen would better display shadow details because of the speed boost. Grain is no issue for me.

1rst was developed in Microphen 1+3 at 14 minutes. (ilford time)
agitation 4 turns of the tank each minute.

2nd was developed in Rodinal 1+50 at 15 minutes. (ilford time)
agitation 4 turns of the tank each minute.

I expected the microphen to be better detailed in the shadow regions because they say that microphen boosts the film speed.
But the two negs look almost the same with the eye when i inspect the shadow areas. I have to make some prints, but i expect no great difference in tone.

Is it because of the dilution of the microphen?
Or is there another thing i did not take into account.

 

[Roger Hicks]

Often Ilford does not give ISO development times. Rather they give the time required for a specific EI. The times given were both, I suspect, for EI 125 i.e. the contrast of the DD-X shot was lower. If both had been developed to the same contrast, and given the same exposure under identical lighting, I am reasonably confident that you would see more shadow detail in the DD-X shot.

This is based on theory and I have not discussed it with Ilford but I would be surprised on this occasion if I were wrong.

Cheers,

Roger (www.rogerandfrances.com -- where there is quite a lot in The Photo School about film speed, subject brightness range, and more).

 

[Willie Jan]

both shots were taken at 125 iso, F16 at 1/30 second.
total range of the shot was 6 stops without the sky.
the first sheet developed in rodinal, the second in microphen.

If it is true what they say, the microphen should have a better detailed shadow area on the photo because microphen would be able to get the 125 speed out of the film. Rodinal would have a EI of around 64 with fp4+, so would the shadow be darker (less information on the negative) than the microphen one. But when i print both negs, the are almost the same, so the microphen one has not gotten more info in the shadows.

 

[timeUnit]

Are you able to print both negs at the same exposure and filtering, and getting equal prints?

 

[Roger Hicks]

timeUnit's question should help answer whether the dev times are for ISO contrast or for EI as I suspect. If you need harder paper for the Microphen the contrasts are different i.e. they are giving times for EIs. Separating ISO and EI is essential to understanding this, and clearly (as one dev gives a speed increase and the other a speed loss) they were not both at ISO 125, even though they were both at EI 125.

Cheers,

R.

 

[Willie Jan]

Are you able to print both negs at the same exposure and filtering, and getting equal prints?

Yes.