Need feedback on my film tests (long!)

[James Smith]

Hello,

I have been trying to calibrate HP5plus film. I am shooting 4x5, and developing in a Jobo drum, which revolves on a Beseler motor base at about 30 revolutions per minute. I am trying to calibrate the HP5 using HC110, dilution H (about twice the dilution of B) @ 68degrees, because dilution B will yield seeming too short development times.

I have previously determined that HP5 should be rated at 200 asa, using the above combinations. This yields a solid .1 over filmbase plus fog.

Here is my (tortured) reasoning for picking a starting development time:

HC110 dilution B, and HP5, with a less vigorous agitation, should be about 5 minutes at 68degrees. From some of my past experience, I was thinking more about 4:45. Ok, so, with dilution H, I should probably double this, to make 9:30 developing time. I subtract 15% due to the constant rolling "agitation" of the jobo drum (per the Jobo web site). So, I arrive at... tada- 8 minutes.

Here is what happened:

http://www.hiddenworld.net/filmtest/test.html

Questions:

1)Does this film curve look properly shaped for my materials?

2)Why am I not seeing any type of shoulder up around zone 9 and 10?

3)I am assuming that the lack of shoulder means that the highlights aren't "blocking up"?

4)Would you consider this curve about an N+1 for traditional darkroom printing?

5)I am probably going to be scanning for digital output, however. Am I right to assume this is a good curve/development time for digital output? More development? Less?

6)If I lessen development, to create a more contracted dual use negative (traditional and digital output), I am guessing that my digital output will slightly suffer from more compacted tone values?

If you made it this far, thanks!

-Jeff

[David A. Goldfarb]

HP5+ produces a pretty straight line curve, so I think it looks reasonable. Just go to Ilford's website to download the technical data sheet with their curves to compare. The lack of a shoulder just means that the film has a higher Dmax than you're using and is a good thing for precisely the reason you've stated--your highlights should have good separation, and you've got some density range left over for N+ development.

If you're getting Zone VIII in the ballpark of 1.2, which you are, that's about normal, so I'd call that about "N". You might find that you like a little more or less depending on your printing process (choice of paper, light source, etc.).

Regarding digital use, it depends on your scanner. If you find you're losing your highlights and seeing a lot of exaggerated grain and banding, try for a thinner negative. You could reduce development time to N-1, and if that works for scanning, just print on grade 3 when you want to print conventionally. Many 35mm shooters do this anyway to minimize grain and maximize sharpness.

[clay harmon]

David is right, but I'll qualify his "HP5+ produces a pretty straight line curve" statement to say that if you are doing alt-process work with large density range targets for your negs, you most certainly will run in to the shoulder on HP-5, generally at about a density of 2.3-2.4. This makes it imperative to not overexpose the stuff if you plan on getting a negative that doesn't have flat highlights, since it is quite easy to push them well into the shoulder with even a 2/3 stop overexposure..

[lee\c]

David and Clay are right on. For my work I might go another 30 seconds to push zone VIII up to around 1.3 or so. I use a cold light and need that extra contrast. But as they have said, you are in the ball park for Normal.

leec

[Henry Ambrose]

What you're getting looks good to me for normal. As far as the digital questions (5 and 6), 6 is probably not an issue you have to be concerned with. You would only lose range if the negs you make have -very- much less range than your scanner. Even if you do have "compacted values" you can re-distribute the values (within reason) to cover the range of your printer and still make great looking prints. As an example, think of XP2 which has a reputation for scanning well - in large part because it will most always give you negatives that fit within the range of most scanners. Not too dense and not too much range, just loads of information that is readily available to your computer.

Anything on the film that is too dense for the scanner to see through will be lost, so stay away from that point. You should test with a scene typical of your actual shooting and try a sheet at N and another at N-1, which would answer question 5.

[Leonard Evens]

I agree with the others that it looks pretty much like a normal characterististic curve for HP5, if I remember Ilford's published curves correctly. Note that this gives you some latitude for overexposure.

You don't say which scanner you are using. Any up to date scanner (with a dmax over 3) is going to have more than enough dynamic range to handle negative film. I've tried overdeveloping to see if this gave me any advantage over normal development in scanning (using HP5), but so far at least I haven't seen much difference.

[Jeff_3801]

Thanks so much for all the replies.

The density readings were actually obtained using my scanner, and Vuescan scanning software. Vuescan has a fairly good densitometer function from which I was able to obtain my film base + fog, and subtract this from the other values I obtained, to create the curve. So, I know these values are in the range of my scanner, because my scanner produced them . I am not sure, however, what the maximum density this scanner could read is- I would assume it would be something above and beyond the shoulder of this film? I am using an Epson 2450 scanner.

Anyway, thanks for the comments and suggestions. I feel much better about being able to reproduce consistant results. Before the testing, I was under exposing by nearly a stop, and over developing by aprox. N+1 or more..

One last question. Judging from the above, any suggestions on what percent to cut / add to my development time to produce N+ and N- curves? These tests are getting expensive, with 4x5 sheet film- don't know how much trial and error I can afford!

Thanks again, Jeff

[Bruce Watson]

James,

First, when you double the dilution, you don't multiply your development time by 2. You multiply your development time by 1.4 (sqrt (2)). That's why you ended up with N+1and not N.

Second, your experience with HC-110, HP5+, rotary processing mirrors my experience with HC-110, Tri-X, rotary processing. I found that HC-110 is difficult to control with rotary processing. This seems to be due to the high activity level of HC-110 combined with continuous agitation. With Tri-X, I found that I still had excessive density/contrast with HC-110H at 5 minutes. I switched to XTOL 1:3 and get much better results.

Third, I've read that HP5+ is not as sensitive (not quite the right word) to HC-110 and continuous agitation, so your times/density readings are not surprising. Neither is your lack of shoulder, although HP5+ is more prone to shouldering than Tri-X, while HC-110 tends to raise highlight contrast levels.

So, to answer your questions directly:

1) yes.

2) HP5+ tendency to shoulder combined with HC110's tendency to raising highlight contrast equals straight(er) line characteristic curve.

3) Highlights don't block up on negatives. They block up on traditional darkroom paper. The zone system was designed to help photographers shoe-horn a scene brightness level that can be ten stops or more through your film, to your paper that can handle 6-8 stops. This shoe-horning is what results in blocked highlights most often, IMHO. Digital printing, in my experience, doesn't have this problem.

4) Yes, because you developed too long. See sqrt(2) information above.

5) My experience drum scanning Tri-X tells me that best results come from negatives that would print well in a wet darkroom. There are lots of reasons for this - a separate threads worth.

6) No. The scanner doesn't care. It's going to take the negative's density range and spread it linearly over a range of numbers (for 8 bit scanning, from 0-255). See number 5 above.

[Mark_3632]

I can't see the link. Is it just on my end?

[Jeff_3801]

link may not work when viewed from behind some company firewalls, as the web server uses port 81. I won't bore you with why I had to do this!