Some testing results - unexpected outcomes.

[welly]

I went out yesterday lunchtime to shoot a batch of tests as I've been a little frustrated with some of my negatives. I metered at 8 seconds for the shadows, 1/30th (it might have been 1/15 though - need to check my notes which are at home) for the highlights in the window and exposed all sheets at ISO50.

I put the shadows in zone 3 and exposed for 1 second at f/16. The film I was using was Fomapan 100 and developed in a fresh batch of D76 at 1:1. I'm using continuous agitation with the BTZS tubes. The tempering bath was at 24c and I let the chemicals in their caps and the tubes with the film in them temper for about 10 minutes so they should have been well up to temperature.

These were all scanned essentially the same way in Epson Scan. I corrected the output settings to go from 0 to 255 and the input settings to stop shadow and highlight clipping, as explained by Ken Lee.

My screen is calibrated with a Spyder 3 Elite although it tends to run a little dark.

So here are the results:

Developed for 3 minutes 30 seconds



Developed for 6 minutes 30 seconds



Developed for 9 minutes 30 seconds (scanned emulsion side up)



Developed for 12 minutes 30 seconds



Incidentally, when I scanned the negative emulsion side down, it was quite a bit darker than the other way round, and so I know to make sure to scan emulsion up.

I think there's probably a bit to get out of this. I'm wondering if shooting Foma 100 at ISO 50 is possibly not right for me. I may start shooting it at ISO 80 or even box speed. To me, with all the above taken into consideration, 3'30" looks pretty much on the money but developing time seems incredibly short considering I'm using 1:1 dilution. But it is exactly how I saw it, so that is good. Of course, I'm scanning negatives in, and my scanner hasn't been calibrated, so it could easily be that the image looks crazy bright to the rest of you. When I look at the negative, it doesn't look particularly thin or thick, it looks pretty good. I'd probably say looking at the actual 6'30" negative, it is probably the best out of them.

What I find most strange is that the window seems brighter in the 3:30 scan than the rest where I'd have thought it would have been the other way round. I will double check I scanned in the right order when I get home. It certainly makes me wonder about scanning and its consistency. Of course, I was shooting these over a period of roughly a minute/minute and a half (I was fairly quick in changing the film holders) so the light outside could easily, and quite possibly, might have changed.

My agitation of the tubes was pretty consistent I believe so a little surprised by the results. Anyway, if anyone has any comments, I'd definitely appreciate it.

[chassis]

These results are consistent with my experience. D-76 can be contrasty with continuous agitation, especially so when fresh.

I started using BTZS tubes with D-76 1:1 and Tri-X. I found myself wanting less and less contrast, and shortened development times over a period of time. Uneven development (streaks along the rotation path - across the 4" film dimension) started appearing. I wanted a workflow with lower contrast, and longer development times (at 68 deg F) so I tried 1:3 dilution, then settled on 1:2 dilution. I also went from continuous agitation to stand (no agitation after 2 initial inversions).

For me this gives the desired contrast, no uneven development, and reasonably short (10-12 minutes) processing times at 68 deg F.

With the lower contrast, stand development and more dilute developer, I am now shooting at EI100. It's working, at least for now.

[Kevin J. Kolosky]

you have a lot of different shadows there. which shadows did you put on zone 3, and what did you plan on being pure black with no detail? Was there any consideration for reciprocity.
And was your bellows draw longer than the focal length of your lens.

[welly]

you have a lot of different shadows there. which shadows did you put on zone 3, and what did you plan on being pure black with no detail? Was there any consideration for reciprocity.
And was your bellows draw longer than the focal length of your lens.

Hi Kevin,

I was using the shadows under the machine on the left (in the middle) for my zone 3. I've got to admit, I didn't even think about what was going to go to pure black. I might have to go back and have a look. There wasn't much bellows draw, certainly not longer than the focal length (was using a 150mm lens) and the Reciprocity Calculator app for my iPhone told me that 1 second on Foma 100 doesn't need any additional exposure.

But I've just read a few other sources that reports Foma 100 needs 1.9 seconds for 1 second. Which may go some way to explain and I do seem to shoot at 1 second a lot.

[cowanw]

If you are comparing contrast and development times don't you have to force one tone (say middle grey) to be the same in each print?

[welly]

If you are comparing contrast and development times don't you have to force one tone (say middle grey) to be the same in each print?

Unless I'm mistaken, that's what I did. I think! These are scans of negatives that in Epson Scan, the middle grey was set to 1.0 for each scan. Now I'm not sure if that middle tone value is relative to a particular negative or if that's a persistent value. I was using Ken Lee's scanning tips and used this method:



as in ensuring my histogram wasn't clipping and the middle tone was set to 1.

[sergiob]

1 sec for Fomapan 100 should bring reciprocity failure into the equation, if my memory is correct. From the examples you posted I think you inverted the order in relation to development times. Looks like it to me, at least.

[welly]

1 sec for Fomapan 100 should bring reciprocity failure into the equation, if my memory is correct. From the examples you posted I think you inverted the order in relation to development times. Looks like it to me, at least.

It looks like it to me too but I will have to check when I get home, but I'm pretty positive that that isn't the case. I remember being very specific in the order I handled my negatives. Anyway, will have a look later.

[Brian Ellis]

Increases in development time primarily affect the highlights, not the shadows. So it's not surprising that all the black/dark gray machinery doesn't change much from one time to another. But what is surprising is that the closest thing to a highlight in the photograph (some of the window panes and the little white square on the right side of the machinery) actually get darker as your development times increase when it should be the other way around. Which makes me have the same question as sergiob - did you perhaps get the development times and images reversed when you posted the images?

[welly]

Increases in development time primarily affect the highlights, not the shadows. So it's not surprising that all the black/dark gray machinery doesn't change much from one time to another. But what is surprising is that the closest thing to a highlight in the photograph (some of the window panes and the little white square on the right side of the machinery) actually get darker as your development times increase when it should be the other way around. Which makes me have the same question as sergiob - did you perhaps get the development times and images reversed when you posted the images?

That's what puzzled me and was what I expected to see. I half expected at 12 1/2 minutes development time for the window to be blown out. I'm going to check tonight and rescan to make sure I'm not going nuts. Perhaps I'll have to run another test.

Anyway, thanks for your input so far!