Calibrating 4x5; gray card Zones don't match still life Zones

[Richie]

I have been getting a lot of inconsistent, unpredictable densities as I have been trying to calibrate my 4x5 camera. I will describe a problem I saw yesterday with idea that somebody might have a hint as to what might be going on. I am a newbie. I am calibrating camera and film and development time and print for an intro to zone class. The teachers have not been able to figure out what is going with me and my camera.

I am calibrating a 4x5 camera (Linhof Master Technika with Fujinon 5.6/150mm lens) , using HP5+400, HC-110 developer, N+1 (development time for this batch was 11'15"), ISO 125. I shot 6 frames and developed them together using tanks and hangers. I shot a gray card with lens cap on for Zone 0, then exposed for Zone I, Zone II, Zone III, Zone VI (1/15, f/64; 1/15, f/45; 1/15, f/32; 1/15, f/11 respectively.) My densities were an absolute 0.09, and net densities of 0.37, 0.63, 0.81, 0.135, the target net densities are 0.10, 0.30, 0.45, 1.05.

The fifth shot was an indoor still life. I placed my shadow detail in Zone III (125 ISO, 1/15, f/14), my highlight detail (Zone VI) was a measured 3 stops greater than my shadow detail. Zone III area on the negative measured 0.24 and the highlight detail measured 0.94. On close inspection of the negative, it looks like I have good detail where I placed Zone III even though I only have 0.24 net density, not the target 0.45.

I don't think the lens magnification factor is an issue. I shot with the lens about two feet the gray card so that I could only have only the gray card on the negative. My 150mm lens was about 150mm from the film plane. Maybe this is called the bellows extension.

In summary, the problem is the gray card densities are 2 or 3 stops higher than I expect them to be AND they are 2 or 3 stops higher than my still light, even though all negatives used the same studio halogen lights and were developed together in the same batch. Does anyone have an idea what might be going on?

[Ken Lee]

You may find this article helpful: http://www.kennethleegallery.com/html/tech/testing.php

[Neal Chaves]

I have explained my HP5+ exposure and development testing procedure below. You don't specify what your dilution of HC110 was or what the temp was. I can tell you that if I rated HP5+ at 125 and then developed for 11:15 in HC110B @68*, my negative would be so dense as to be unprintable.



Years ago I learned the method to find the correct developing time and EI for any film. I source was an article by William Mortensen. Mortensen wrote some excellent books and articles about basic sensitometry. The last time I did this test was when I abandoned Tri-X and switched to HP5+ due to cost about five years ago. I proceed as follows.

I set up my trays with my favorite developer HC110B (1:31). I pull out a sheet from the package in the dark. and then when the package is sealed again I turn on the room lights. This part of the test is done under the lights. I cut the sheet into five strips and mark them 1-5 by punching holes with a paper punch. Lets say the recommended time is 5:00. I want to see 3:00, 4:00, 5:00, 6:00 and 7:00, so I throw all the strips into the developer and agitate as usual until 3:00 when I move the No.1 strip over to the stop bath. Then I pull No.2 at 4:00, No.3 at 5:00, etc. I fix, wash and dry the strips as usual. What we are looking for is the best usable film DMax value. Obviously the film has been fully exposed! When strips dry lay down a page of news print on a table in good light. Find the strip through which the news print is barely visible. That's your developing time. Now to find the film speed.

Go outside in unchanging light conditions and expose five sheets and expose one at the manufacturers rating and then the other four at one half a stop and one stop less and one half a stop and one stop more. In the dark, develop them all together for your newly derived time. Contact print them together exposing and developing the paper for maximum usable paper DMax value. Pick out the best-looking contact print and you have your film speed.

Because my 7:00 negative looked the best on the first test, I did the test again with 7:00 as the central developing time and found that 8:00 was indeed too dense. This HP5+ time was the same as the as the developing time I had been using for Tri-X and film speed was also the same, EI400.

Many of the last generation of B&W gurus favored a development time of 5:00 for Tri-X and suggested an EI of 64-100. You can do the above test backwards, developing for 5:00 minutes and finding the film speed. I like 100. The difference between negatives exposed at 100 and developed for 5:00 is quite subtle. Both could be considered "normal" or N negatives. The 100 negative has slightly greater shadow and highlight detail that only a careful, knowledgeable viewer could detect. This slight improvement might not be worthwhile trading for two stops in the field. I do routinely rate HP5+ at 100 under powerful strobe light in the studio and it produces beautiful skin tones.

From here, if you are still with me, you can derive expansion and contraction schemes for both the 100 and 400 "normal negs". I do this by changing dilution rather than time. Make sure you have at least 1 oz. of the concentrated sauce for each 8X10 sheet or equivalent. For contraction I found that 3/4 oz. concentrate to 31 1/4 ozs. H20 yields an N-1 neg at a one stop loss in film speed and 1/2 oz. concentrate to 31 1/2 ozs. H20 yields an N-2 neg at a two stop loss in film speed. For expansions, 1 1/4 oz. of concentrate to 30 3/4 ozs. H20 yields an N+1 neg at a one stop gain in speed and 1 1/2 ozs. concentrate to 30 1/2 ozs. H20 produces an N+2 negative with a two stop gain in speed.

If you look at the chart of Tri-X film speed in Phil Davis' BTZS book you can easily pick out the film speed in HC110B 5:00 as EI 64.

Don't apply reciprosity exposure and development corrections for long exposures (1/2 sec. +) based on published data. Test for yourself and you may be surprised. I wasted a lot of time and effort producing long exposure negatives that were thick and flat. When I finally tested, I found no compensation was required for TXP out to one minute.

If you are curious about the density of very low values, don't expose with the lens cap on. All lenses, even the latest multicoated ones exhibit some flare which will affect low values. Instead, make a target box at least a foot deep and cover the back wall with black velvet. Then expose normally for the surrounding scene and later measure the density of the black target area.

[Richie]

You may find this article helpful: http://www.kennethleegallery.com/html/tech/testing.php

Thanks Ken. I did find your article helpful. If I can't find out why I am getting different gray card densities than scene densities on this thread, I will abandon shooting the gray card and try to calibrate using scenes. I found your recommendations about how to shoot scenes for calibrating very helpful. I also plan on scanning as well as darkroom printing of my negatives so I am eager to study your recommendations for scanning film.

[Richie]

Neal, my dilution was E (1:47) and my temperature was 68 degrees Fahrenheit.

[Neal Chaves]

HC110 is so economical that I see no need to dilute it more than 1:31 (B) except for the N-1 and N-2 above to give a longer working time. One must use at least 1 ounce of the concentrate per 80 sq. inches of film to ensure complete one-shot development with a 100% safety factor. When you use very dilute mixtures, you need a lot of water in large trays. You can't do it in small tanks. I got away from tanks and hangers for development years ago and learned to shuffle the 4X5s and 8X10s in trays. Now when I do 8X10s I usually develop only one sheet at a time face up in an 8X10 tray. Now I am using Ilford Ilfotech HC at the exact same times and dilutions as HC110 and notice no difference. Most dealers will not ship HC110 and the Iford is less expensive as well.

[faberryman]

I'm curious; why are you using HP5 Plus at ISO 125? That would be almost two stops overexposed. That may explain why you find that your "densities are 2 or 3 stops higher than I expect them to be".

[ic-racer]

I don't know of any useful film/paper testing method whereby one matches scene density values to print values 1 to 1 outside of copy work.

[Andrew O'Neill]

EI 125 is pretty low for that film and developer combo. You have done an EI test, correct? Almost everyday conventional and staining developer that I have used requires an EI anywhere from 200 to 250. You need to lock that in first before you proceed.

[Bill Burk]

I agree with faberryman and Andrew O'Neill,

You are getting results that look like they came from a 400 speed film. You did a series of Zone System exposures at 125, but the film is a 400 speed film. It's responding like a 400 speed film to the increased exposure that you gave it, so you are getting higher densities than the target. Your densities look good for a 400 speed film.

When you took your photograph of the still life, it seems you gave it an exposure appropriate for a 400 speed film.