Disclaimer: If you are looking for a well-throughout, well-executed and well-analyzed test done according to industry standards written in industry jargon, I’m afraid you have to look elsewhere.
I wanted to test if it was possible to increase or decrease the contrast in New55 Atomic-X film developed in New55 R5 Monobath. I’m not sure what I can do with agitation or time emerged in liquid, but now I tested exposure time. I took two exposures of a still life setup, one with short exposure time and one with long exposure time and compared the negatives.
The two exposures were done back to back on the same equipment and in the same lighting condition (no filters). My incident-light meter read EV 9 which gave me the two exposures as:
1) f/5.6 and 1/15 s
2) f/64 and 8 s, which I compensated to 50 s due to reciprocity.
But I really messed up the second (the long) exposure since 8 s should be adjusted to about 37-38 s according to the reciprocity information provided by New55. My bad, but I think we can still get some information from this test. But remember the long exposure is overexposed compared to the short exposure. The negatives were developed simultaneously in the same tank, and later scanned in an old Agfa Duoscan T2500.
Figure 1 is a photo of the scene captured on my iPhone, the gray floor is quite close to a gray card. The statue made of gypsum and is positioned on a sheet of A3 typing paper.
Figure 2 shows the TIF-scans of the negatives seen as they were exported from scanner, a RAW format would probably be better but I think this is ok for now.
Fig2.pdf
As you can see in Figure 2, the development is in uneven over the negatives (there is a “pouring-pattern”), and since the negatives were places in the tank face to face different parts of the two negative have been hit by the pouring liquid. I use a Combi Plan tank, which is not suited for R5 Monbath unless you can plunge the film directly into the open tank in total darkness (as recommended by New55). I don’t have total darkness anywhere outside my changing bag so I’m limited to using the narrow ports. The pixel intensity line plots show that the bright side of the nose is saturated in both exposures and the floor boards have very different intensity in the two images. I’m not sure how much the scanner is to blame for the saturation; perhaps a better scanner can penetrate the dense parts of the negatives. You can also see that the non-exposed areas of the negatives (the areas hidden in the film holder grooves) are completely black while there is some intensity in the very dark areas between the floor boards.
Now in hindsight I realize that it is almost pointless to compare images with such different depth of field. There is almost no texture in the floor boards in the short exposure image but plenty of texture in the floor boards in the long exposure images. I should of course use neutral-density filter to adjust the exposure time. I should also have found a better subject with both dark and bright regions.
In Figure 2 I have also marked four small areas of interest in the two images. “SE” is short for short exposure and “LE” for long exposure. The pixel intensity valued for the eight areas are:
___SE | LE
1: 220 | 225
2: 108 | 145
3: 027 | 057
4: 015 | 006
The histograms can be seen in Figure 3.
Fig3.pdf
The area with the highest intensity while still having some texture (position 1 in both images) are very close in intensity (a difference of only 5 units), even though one image is overexposed. The two mid-gray areas (position 2 and 3) have both increased with about 30-40 units due to the overexposure in the long exposure. The very dark shadow (between the floor boards in position 4), actually have lower intensity in the overexposed image. This is, however, most likely due to the increased depth of field in the overexposed image. The floor board gaps are smeared into gray goo in the short exposure image while being clear and distinct in the long exposure image.
It is hard to say how the long exposure time affected the contrast, but it seems the contrast increased quite a bit in the darker areas while still maintaining acceptable in the brighter areas. It seems that the very bright areas are affected much less by overexposure than the darker areas. Is this finding true for all overexposed negatives developed in R5 Monobath, independent of exposure time (shutter speed)?
Now I would like to find a better subject and capture 3 images and with the aid of neutral-density filters keep the aperture constant.
1) One image at normal exposure and short exposure time
2) One image at normal exposure and long exposure
3) One overexposed image at short exposure time
Questions, suggestions or other feedback?
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