Subjective Film Test...
Subjective Film Test...
Glenn: I'm actually interested in your results, as I've never seen anything like this done in-print.
I do recall the color-film "shoot-outs" done in the mainstream mags. The thing is, since new-film introductions were relatively glacial in frequency, I only needed to glance at one such article for an overview, not each and every year. (But magazines need to crank stuff out every month, so...)
- Barrett
Barrett,
This is a loosely constructed subjective experiment. I was an analytical chemist by day in the 70s & 80s. Part of my job was calibrating spectroscopic plates for one of the instruments. I applied the same techniques to the B&W films I was using. After a couple of years of experimenting I discovered that the variation in camera & lens performance, lighting, tap water, and other parameters exceeded most of the variation in the films I was using. Now, when I try a new film, testing is fairly simple.
1. Pick a developer
2. Pick a trial EI
3. Make some test exposures
4. Develop the film with a trial time
5. Evaluate the contrast
6. Evaluate the Zone I density to determine if the trial EI was OK
7. Adjust the development time if the contrast isn't what I want
8. Adjust the EI to get the Zone I density where I want
9. Go back to step 3 and repeat until the contrast is where I want it and I have determined a satisfactory EI.
Because the experiment includes a particular camera, lens, enlarger, paper, developers, etc. contrast and EI are dependent on the equipment and techniques I am using. Your experience may vary.
I'm not measuring grain, tonal separation, or sharpness... no micrographs or fancy calculations. I'll just make some subjective judgments along these lines:
1. Does the negative print with the tonal separation that I want on the paper I want to use?
2. How does the negative scan?
2a. Do I get excessive grain aliasing?
2b. Are the high zones blocked?
3. How does the grain pattern look?
4. How do the details in the smooth regions of the image look?
5. How is the overall sharpness?
I'll post some results as the experiment progresses. I have to finish one more roll each of Kentmere 100 and Acros, so I should have some preliminary data on them next week. There is almost nothing available on the Kentmere film, so I'm particularly excited about it. I have to buy some 5231 before I can get to testing it. It's cinema negative rated at ISO 80, but because cinema films are rated for a lower gamma, it will probably manage EI 100 - 125 when processed to the higher still film gamma. 5231 is in this list because cinema films usually have longer tonal scales and wider dynamic range compared to their still counterparts. However, one has the inconvenience of loading cartridges and their lack of frame numbers.
More as it happens... back to my day job.
Glenn