MattKing
Moderator
Thanks Nick - this is truly appreciated.
I noticed that too, but Catlabs sells directly to the consumer for less. The Catlabs film you shared there is the old version I think, rather than the "pro" version. They are easy to confuse.$8.99 vs $9.00?
CatLABS X Film 320 Black and White Negative Film (35mm Roll Film, 36 Exposures)
Buy CatLABS X Film 320 Black and White Negative Film (35mm Roll Film, 36 Exposures) featuring Panchromatic B&W Negative Film, ISO 320/26° in Standard Process, Fine Grain Structure, Wide Exposure Latitude and Tonal Range, Loaded in Plastic, Reusable Cassettes. Review CatLABS X Film 320www.bhphotovideo.com
But Catlabs already stated:
Sorry, you are right, it must be the 2019 incarnation of X 320 on the B&H website.The Catlabs film you shared there is the old version
$8.99 vs $9.00?
I paid about $6-$6.50 per roll for the ten roll pack I ordered direct from CatLabs. I have to presume and expect that B&H is taking a markup (not least to price in their "free" shipping).
Fantastic. You are right. I just confirmed it by opening up the manual, which has been sitting on the shelf all along. So all I need is a RS-232 to serial cable plus a serial-to-USB adapter, yes? I owe you one. This is going to simplify things a lot. Thanks!
You bring up a very interesting point. There is a reason the 0.1 criterion has been so widely adopted by the photographic community over the decades, esp. by Zone System and BTZS photographers, as it allows one to produce consistent negatives with ample shadow detail and a very malleable family of curves that can be easily controlled with development (usually from N-2 to N+2). Lambrecht and Woodhouse (Way Beyond Monochrome, 2003) take it even further and suggest using Zone I.5 density or 0.17 above B+F as speed-point reference. This will allow even more shadow detail, at the (small) expense of film speed.Thanks Nick for all your work. I had only ever heard of Kodak's Contrast Index(C.I. ) and Ilford's G-bar and my impression is that those 2 are pretty close but in fact there are 4 with quite a spread of speeds which in this case is nearly a stop
Without wishing to stray from the reason for the thread I wonder, just as an idle musing, what the like of HP5+ or TMax 400 might be in the Delta X method? Maybe at least 650 or even 800?
pentaxuser
You bring up a very interesting point. There is a reason the 0.1 criterion has been so widely adopted by the photographic community over the decades, esp. by Zone System and BTZS photographers, as it allows one to produce consistent negatives with ample shadow detail and a very malleable family of curves that can be easily controlled with development (usually from N-2 to N+2). Lambrecht and Woodhouse (Way Beyond Monochrome, 2003) take it even further and suggest using Zone I.5 density or 0.17 above B+F as speed-point reference. This will allow even more shadow detail, at the (small) expense of film speed.
The reason why I decided to do the comparison between different speed-point methods was to offer some sort of data-based explanation for why some people are getting results they like by exposing the Catlabs film at EI 100 and EI 200. Those "old" criteria were based on print-judgment data, so there was an additional step involved, i.e., the creation of a "first acceptable" silver gelatin print, so there might have been be some loss of shadow detail. These days, it seems, most people, especially those that are the target demographic for Catlabs, scan film by DSLR, process in Negative Lab Pro + Lightroom, and share electronically, often forgoing printing altogether. Therefore, it does not seem unreasonable that they should be getting great photographs (esp. of the punchy or moody variety) with the Catlabs film in a hybrid process, even if they are sacrificing (some) shadow detail.
Great examples! Thank you for posting the link.@ aparat, congratulations for your thorough work and clear presentation.
Back to the "paradox" of some people obtaining "OK" results at box (320) speed. Have a look at this testing of a mainstream film, HP5, there: https://carmencitafilmlab.com/blog/hp5-delta400/
scroll down halfway for a series of over (not our topic) and under-exposed pictures (click to enlarge)
Sure, the frame at -3 is a little washed out compared with the nominal exposure, but taken alone it is sort of OK. EI-320 -3stops is EI-40... And the people who shoot that new Catlab film at 320 do not bother to try exposing it 1, 2, or 3 stops more to see if it would improve the image quality.
I have found an illustration of how an underexposed negative can still produce pleasing results, in theory. Back in the 1950s and 1960s, there was some interesting research trying to determine what exactly makes a properly exposed negative, and to define all the formal parameters related to that (e.g., film speed, Average Gradient, Contrast Index, etc.). One of the key concepts was the first acceptable vs. first excellent exposure (as in, a negative that can be turned into a print). As I showed earlier (I am including the curve again here), the 0.1 criterion leads to better shadow detail, at the expense of film speed, whereas the Fractional Gradient (0.3G) method is more about getting the first "acceptable" negative, so you can sacrifice some shadow detail, but gain some speed. I suppose this distinction can, to some degree, account for the fact, as you very nicely point out, "one can get away so easily with underexposure." I think this is particularly true today, when scanners and/or DLSRs can get a lot of data out of a negative, and software can turn it into a very pleasing image.I'm still puzzled that one can get away so easily with underexposure, but at least it seems to be nothing special with the Catlabs 320 film.
It also has significantly higher B+F density (0.28).
If wishes were horses...
I'd be interested in seeing a comparison with one of the "3200" films
This is interesting. The B+F level in Ilford technical data sheet is much lower than that:
View attachment 319628
The curve is for 8 min in ILFOTECH HC 1+31. The equivalent time in D76 1+1 would be 11 min.
Are you getting consistent F+B levels with the sensitometer and your DIY setup? It is probably best compared on faster films.
It would be interesting to compare your FP4+ curve with the Ilford data. They use relative log exposure so there's an arbitrary shift along the x-axis. PM me if you need help with plotting and analysis, I'd be more than happy to help.
Once again, thanks a lot for doing these experiments. You have achieved amazing results and I hope more are coming!
If wishes were horses...
I'd be interested in seeing a comparison with one of the "3200" films - Ilford Delta 3200, or Kodak TMax P3200.
Can we crowd-fund Nick? Buy him film and chemistry and whatever else he needs?
I would expect a film manufacturer to provide free samples (and a lot of assistance) for research like that but this is clearly not happening with Catlabs.
I might as well get a couple of rolls of TMax 3200. I haven't used this new (is it new?) version yet.
You are correct, the curve is for roll film. Sorry, I overlooked this. 35 mm, type 120 and sheet film are coated on different bases, according to Ilford. That could explain different base levels.The graph you showed probably comes from 120 or sheet film.
I don't know much about how film base differs across different products. Perhaps someone can chime in and explain the differences.You are correct, the curve is for roll film. Sorry, I overlooked this. 35 mm, type 120 and sheet film are coated on different bases, according to Ilford. That could explain different base levels.
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