Sensitometry for stained negatives

[Milpool]

Interesting results and not surprising. Thanks for posting this.

A long time ago, I teamed up with Kirk Keys over a similar question. He felt there was some special properties in staining and I believe it had more to do with the development velocity. We ran a bunch of film, but didn't get much past that stage. Below are the results for FP4P developed to a CI 0.56 in Xtol and PMK. Part of the print testing was going to determine which read densities best represented the results. If I remember correctly, I felt the Visual setting is most likely represent how the film would respond in an enlarger's light.

View attachment 413023 View attachment 413027

 

[tcolgate]

Interesting results and not surprising. Thanks for posting this.

It's very useful to know that measuring blue is not really that useful for regular enlarging. Measuring through the filter is a PITA and I might not bother in future.

This caused me to notice something interesting in the Unblinking Eye staining developer article. One of the only films there that is analysed with the same dilution and dev time in both blue and UV is HP5+ at 2+2+100
fig12 is UV

fig20 is BLUE

This does raise the question of why UV and BLUE were chosen (vs UV and vis, which would have been different, there's a few bits in the article that are a bit of an irritant in trying to compare the various charts).
This would seem to imply that measuring a blue channel might be useful for checking density range for alt processes maybe? No substitute for a UV densitometer, but I've not long brought my printalyzer, and can't really justify upgrading to the UV version.

 

[BHuij]

I have been proceeding under the assumption that agitation is going to indirectly affect EI for the reasons I specified above - more agitation = faster highlight development = less time for shadows to develop = lower effective EI at a given contrast index.

But now I am curious enough to challenge that assumption. Maybe I'll cut a roll of HP5+ in half and develop one half with my normal Ilford agitation and the other half rotary to see if the densities come out differently. Rule of thumb is to cut development time by 15% for rotary processing, right?

Is sheet HP5+ emulsion different from roll HP5+ in a way that would change development between the two?

 

[Stephen Benskin]

For reference here is the original specified formula. It's different than D-76/ID-11. Apparently one of the reasons for the standard change to remove the specified developer was that Kodak had trouble getting the earlier T-Max films to quite reach box speed with it (recall there was a time when the T-Max films were labelled EI rather than ISO).

(/l)
0.5g metol
40.0g sodium sulfite (anh.)
1.0g HQ
1.5g sodium carbonate (anh.)
1.0g sodium bicarbonate
0.2g KBr

pH 9.4 +/-0.2 @ 20C

At that time the standard also specified the fixer formula.

Regarding gamma in the standard keep in mind this is required between the speed point (Hm) and a point Hn 1.3 logH (4 1/3 stops) higher. In Zone System parlance that would be the range from Zone I 2/3 to Zone VI.

Just to clarify for everyone else, and I hope this isn't overly pedantic, but there is no gamma in the standard or at least not the gamma term referring to the measurement of the straight-line portion of the curve. Nor does it use CI or G-bar. Technically you could use the generic version of gamma (simply rise/run for any given portion). It just doesn't have a corresponding gradient method. It's more of a contrast parameter. The film curve needs to fit the parameters. The Δ1.30 log-H and Δ0.80 density range (ΔD) equals a gradient of 0.615. A short-toed film will have an approximate average gradient of 0.61 under these conditions. A long-toed film will have a higher average gradient of 0.65 or slightly higher. The reason for this is to fit the mathematical conditions to fit the Delta-X equation.

 

[tcolgate]

I have been proceeding under the assumption that agitation is going to indirectly affect EI for the reasons I specified above - more agitation = faster highlight development = less time for shadows to develop = lower effective EI at a given contrast index.

One factor with Pyrocat is also oxidation. I usually use 1+1+100 and ilford agitation, but I noticed that when doing 4x5 in an SP445, the developer is notably less brown after the finished dev time. I've put this down to the sp445 just being a bit fuller, and me having a less aggressive inversions (because the thing leaks badly enough without extra encouragement). This caused me to be a bit more gentle with my inversions when doing roll film in a patterson.
I've not tested to see if this is keeping the developer a bit more active for longer. I need to do a proper test at some point.