UPDATE: here's a link to our Foma Data page: https://shop.stearmanpress.com/pages/film-data-foma
Overview: We've been testing FomaPan 200 Creative with our SP-76EC developer. The above curves are from a standard 21 step tablet and measured with a densitometer. All shots taken with a calibrated shutter. Click above to download a larger version.
The Film: Foma boasts that this is a new generation film. It features hexagonal core/shell tabular silver halide grains that is supposed to have better resolving power and lower granularity. So kind of like TMax but only kind of. What we've seen so far, we like.
However, we really wanted to understand it before we really started using it. So we ran it though our test procedure.
Speed: Our tests indicate that this film should really be exposed at ISO 100 for the best shadow detail (the curves above were exposed at ISO 100). We got pretty good results at ISO 125 and acceptable photos at ISO 160, though by then the shadows were a bit weak. Also, we didn't see the reciprocity failure kick in at one second like Foma claims it would; of course, we're exposing at ISO 100 instead of 200.
Gamma: You may wonder who decided that's the "ideal slope". Kodak did, and Ansel preached the same message. This is the standard Gamma = 0.62 straight line that the industry has used for decades. We've positioned the reference line to start at the Film Base + Fog + 0.1 (also standard industry practice).
But is it the right slope for you? That we don't know but we don't want argue with Kodak and Adams. Frankly, it looks pretty good to us.
Zone control: Traditionally, people control the contrast by adjusting the development time. We took a somewhat contrarian approach and varied the concentration of the developer. In fact, we kept the everything else constant:
- 450 ml of water + varying amount of SP-76EC
- 68°F/20°C
- Development time: 7:00 minutes.
- Agitation: constant agitation for the first 15 seconds, then 10 seconds every minute.
There are several reasons for this approach. First, we like to eliminate as many variables as possible; this locks down everything but the amount of developer. Also, we don't like short development times; nor really long ones. Seven minutes feels just right.
Here's our ratios, 450 ml of water + x ml of SP-76EC.
9+1: 50 ml
11+1: 40 ml
14+1: 32 ml
19+1: 24 ml
Okay, for exact ratios the 450 ml would have to vary or you'd end up with odd amounts of developer. Feel free to calculate out the exact numbers to the 0.1 ml if it makes you feel better. Frankly, 5-10 ml of water isn't going affect your results.
Shaking things up: We also changed our agitation scheme. While Foma claims that this film has the same exposure curves as their 100 and 400, we think it's a bit more contrasty. (Of course, we need to go back and retest their other films. It's been years since we first evaluated them and both our methodology and test equipment have improved.)
We finally settled on agitating continuously for the first 15 seconds and then for 10 seconds every minute.
Minor note: all testing was done in the SP-445; we'll be repeating the test with the SP-8x10 just to see if there are any differences.
Of course, standard disclaimers apply; your results will probably vary. If they do, the most likely cause is your shutter. It probably sucks. Unless it's relatively new or has just been CLA'ed, it's probably not very accurate. By "not very", I mean +/- 50% (probably minus, they're usually slow). It will also vary with temperature and the amount of use. That's going to be the topic of another blog post...
We should mention that this film is very forgiving; we overexposed (ISO 50) and underexposed (ISO 400) and still got "usable" negatives. You should experiment and find the ISO rating and processing scheme that fits your needs.
Now that the formal testing is finished, maybe we'll find time to take some real photos.