Neopan 400 dev time strangeness

[revdocjim]

I haven't read through too many posts here so forgive me if this topic has been discussed.
I am puzzled by the developing times for Neopan 400 (and 100). When using Fuji's SPD it is very fast, only requiring 4.25 minutes at 20 degrees.
And yet with D-76 this film requires about 6.5 minutes. Neopan 100 requires over 7 minutes. The strange thing is that with most other emulsions SPD and D-76 times are almost identical.
I'm not just quoting "book" times but have verified the above numerous times in my own experience.

Is SPD specially formulated to work on Neopan film faster than others. Is that even possible?

 

[Thomas Bertilsson]

Does the answer really matter? As long as you get good negatives, I mean.

 

[revdocjim]

Nope! Just curious to know more about how these things work.

 

[pentaxuser]

It's a fair question and one that must have an answer. I wonder what it is?

pentaxuser

 

[Helinophoto]

I would believe that a Fuji developer is kinda designed for Fuji films -some how-

 

[Thomas Bertilsson]

I would say it depends on how they test films, and to what contrast they develop them.

If you remember old Agfa APX spec sheets, they would publish curves and development times for three different gamma curves.

It could be that Fuji's testing methods are simply different from other chemistry manufacturers. Either way, to make a fair comparison, whatever developers you are comparing, they must be developed to identical contrast to bear validity. This requires fairly standardized procedures, a precise lab environment, and all 'other things' equal.

The layman's version is to make negatives that print well on the same paper at the same contrast grade and magnification.

 

[revdocjim]

Thomas,
Thanks for the info.
I wasn't aware of the variations in testing standards. I guess that makes sense, although my very unscientific experience with both Neopan 400 and 100 is that after 4.25 minutes in SPD the results do not look low on contrast at all. If anything this is a slightly punchy film with very distinct contrast. And yet when I process it for over 6 minutes in D-76 I get what appears to be similar contrast levels...

But I do need to do a few more rolls in D-76 to really get a better idea of the results.

 

[john_s]

I would say it depends on how they test films, and to what contrast they develop them.

If you remember old Agfa APX spec sheets, they would publish curves and development times for three different gamma curves.

It could be that Fuji's testing methods are simply different from other chemistry manufacturers. Either way, to make a fair comparison, whatever developers you are comparing, they must be developed to identical contrast to bear validity. This requires fairly standardized procedures, a precise lab environment, and all 'other things' equal.

The layman's version is to make negatives that print well on the same paper at the same contrast grade and magnification.

I seem to remember that Fujifilm's recommendations using Ilford and Kodak developers were different to those two manufacturers' recommendations for the Neopan400. My recollection is that the Fujifilm recommendations suited me better.

Example: Fujifilm's recommendation for Neopan400, 35mm, 400 speed, Xtol 20degC, small tank, intermittent agitation: 6.25min

From Kodak's pdf for Xtol: same conditions: 8.25min

Perhaps Kodak wanted people to say the Neopan400 isn't any good because highlights blow out or something like that.

 

[revdocjim]

Ah hah! Evidence of an anti-Fuji conspiracy...

 

[Thomas Bertilsson]

Example: Fujifilm's recommendation for Neopan400, 35mm, 400 speed, Xtol 20degC, small tank, intermittent agitation: 6.25min

From Kodak's pdf for Xtol: same conditions: 8.25min

Perhaps Kodak wanted people to say the Neopan400 isn't any good because highlights blow out or something like that.

Or, they think more mid-tone and highlight contrast is a technically better negative. I often find that I get more interesting tonality with a negative that's developed a bit longer.
How you develop your negative also depends on how you print them. You can measure differences in film curves all you want, but if it doesn't suit the paper you print on, or the paper developer you use, then none of that is worth anything. Same idea, but a different target.