Following the not-complete-failure of my first attempts at reversal processing, I decided to play with a tried-and-tested developer, namely Dektol. To provide me with a set of test images, I photographed my shoe rack 4 times, giving me identical negatives to start with. In this case, the film used is 4×5 TMAX-100 film.
For the first trial, I decided to use Dektol diluted 1:2, with 0.25 mL of sodium thiosulfate (250g/L) in 60 mL of final developer volume. Development was performed on a motorized base for 12 minutes in a BTZS tube. There is a problem with using these tubes, which I will mention later.
After the first development I rinsed with lots of water, and bleached with the same under-strength potassium permanganate/sulfuric acid bleach for 6 minutes. Using around 1 tablespoon of Iron-Out, I tried to clear and fog/develop my slide. I had some success initially, obtaining a slide of adequate contrast. However, I found that the slide did not clear well – there was significant staining of the slide, yielding a yellowish slide. Reasoning that the fogging developer will, in any event, result in complete conversion of the halides to silver, there will be no harm in increasing the concentration of the Iron-Out. So I cranked up the concentration ~ 5-fold, and left the slide in for minutes. And since I didn’t have a large enough container on hand, I was only able to submerge half the slide at any time. There was no significant improvement in clarity, but I ended up with uneven density in the highlights! It was clear that there was residual halide in the emulsion, meaning that I should use a higher concentration of thiosulfate in the first developer, or fix the film after appropriate second development. There was also a clipping of the highlights in the image along with nice, strong blacks in the shadows, indicating excessive contrast in the image.
I repeated the above, except now, instead of using Iron-Out for clearing, I used a 25g/L sodium metabisulfite solution. This allows me to clear for an extended duration without fogging the highlights. I also attempted to reduce the second development time to improve the highlights. While the two images in the gallery above look disappointingly similar, that is primarily because of the scanner autoexposure function. When placed side-by-side (below), the image from the second attempt (left) is much less yellow, and has retained a lot more highlight details (see: picture in frame and clipboard on door). The contrast on the second attempt is definitely lower, and I wonder if it might not have benefited from an extension of development to darken the shadows more. The highlights are also not as clear as I want them to be, so I may increase the thiosulfate concentration in the next attempt.
Issues with BTZS Developing Tubes
The use of BTZS tubes allow for hands-free processing. However, because the tube is completely smooth, when I place the rolled-up film in the tube, it contacts the tube along the middle of the frame, preventing chemicals from accessing it. In addition, chemicals have a tendency to pool along the sides flanking this middle portion, resulting in the rather distracting yellow stains on the film. This is a definite problem, and I think I will have to engineer some solution before I use the tubes again.
All things considered, this is not a bad result. I will be testing out a few more conditions before a follow-up post. I will also write about my experience processing 16mm movie film for the first time in a Morse G3 tank. Stay tuned!