Slightly off topic...
I do not - and think many doesn't also have access to a densitometer.
So, if I place the camera closely facing a evenly illuminated wall, lens at infinite focus, take a series of shots - normal reading, 1 stop less light, 2 stops less, ...., 4, 4 1/2, 5 stops less, develop normally (at manufacturer's recommended time) and print two adjacent frames at once (including the border area between two frames):
Suppose that between 4 1/2 stops and 5 stops I can notice that 4 /12 is lighter than interframe (film base) and 5 is as dark as interframe, is this 4 1/2 stop less close enought to Zone 1?
It would seem, at first glance, that what you suggest would work. I have found in my experience that it will not be accurate. The reason is that Zone I, Zone II, and approaching Zone III all fall on the toe of the film's characteristic curve. Typically, these tonalities will also fall on the shoulder of the paper's characteristic curve. Therefore the negative densities and corresponding print tonalities are not well separated there.
I have heard that most humans can visually distinguish a film density change of .07 and above. Therefore if one has no access to a densitometer, I would rely on a visual inspection of the film before I would rely on the tonal difference in the print that you suggest. I think that this would be more accurate.
There are two threads on making your own densitometer. The one I made is very cheap to make if you already have a digital multimeter.
That's one point not clear to me:
I do the exposure series and looking at the negative I obtain my personal EI.
Now, if I print the test strip and there is no difference in paper between -0.5, base, +0.5 frames it doesn't matter.
My viewpoint is that I should use as minimum density the one that gives first dark gray above black on a normal grade paper print - not in the negative.
i can't see what's wrong with this idea.
Ok, I got my densitometer readings back.
Film base value reading was 34
In both the incremental readings f 5.6 gave a value of 43
With my camera lens set on infinity, my in camera meter indicated that to capture the gray card I should use a shutter speed of 125 and an f stop of 2.8.
So that means, if I understand all this, that in order to get a Zone 1 I need only close down my aperture to f 5.6 rather than to f 11.
That being said what would I change my ASA setting to on my camera? I have the option of two dots between ASA numbers i.e. 100, dot, dot, 200. So the space between numbers is divided into thirds.
I presently have my ASA set at the first dot over 100 for FP4 which is 125 film meaning that I am exposing for a little less time than would be absolutely correct.
Whew, how I hope all that is correct! Now if I shoot a roll with several frames at Zone VIII and the rest at Zone 0 to Zone 10 I will find out if my film development time should be more or less because my Zone VIII reading should be 1.2.
If I can get modification advice on my ASA adjustment I can still, maybe, have time to shoot the Zone VIII test today—my store support being closed tomorrow. I would love that but I understand it is Friday afternoon so don’t worry at all anyone if you don’t have time to reply to my little problem right away you have all been great!
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I went to Brian’s book and looked up his modification chart for ASA. For two stops over he suggests setting the ASA at 32 (rounded number). That would be one dot over the number setting of 25 on my ASA dial.
Jeez, that can’t be right… can it? That would be way, way over shooting, my negative would look like a roofing shingle.
Operating on the basis of the information that you have provided. (Film speed set at 125 on the camera and metering and exposing as we have discussed). If the film were exposing as advertised in your system, then 1/125 second at F11 should have given you a net density (after subtracting FB+fog) of .10. However the densitometer test indicate that this occurred in the exposure that you made at F 5.6 and 1/125 second. This indicates that the film is exposing in your camera and the meter that you are using two stops slower then advertised. This would mean that the film is in fact exposing at EI 32. My question is did you manually set the exposures on the camera with the film speed set at 125?
This seems to be an excessive compensation from the mfg advertised speed, in my experience with Ilford. If I were you I would check the meter reading on this camera against your other camera in the same lighting conditions. (Gray card, evenly lit...lens set at infinity and card filling the frame.) If your two camera meters agree, then I would shoot the film at 32. I suspect you have a meter problem, but check against another meter.
If in fact you find that the two meters agree in the same conditions and the film speed is determined to be 32 in your system then the next step is to expose under the same conditions (gray card, evenly lit, camera film speed set at 32, lens set at infinity and card filling the frame) manually set your lens and shutter speed to three stops open from what the meter indicates. This will be a zone VIII exposure. I would shoot the entire roll at this exposure, cut the roll into three even lengths and develop one at 20 % less then recommended, one at 15% less then recommended, and one at 10% less then the recommended development time. Have the density read on those strips . The one that will give you a density of 1.10 over FB+ fog will be very near your development time for printing on grade 3. The one which will give you 1.20 over film base plus fog will print fairly well on grade two.
To answer your earlier question as to my reasoning on printing roll film negatives on grade three paper, the longer that you develop film the more grain becomes apparent. This is most apparent on roll film (small negatives where degree of enlargement is greatest). By reducing development on roll film, we reduce contrast but we also reduce grain. We compensate for the lower negative contrast by printing on a higher contrast paper because grain is not an issue on paper.
The way Barnbaum does it is to move the center part of the exposure up the curve. This way the lower zones don't get all muddled up on the toe.
As an example he uses Tri-X 320. He rates it at 160asa and then exposes shadows for zone 4. Effectively he is rating the film at 80asa with a zone 3 shadow placement. To develop he takes his HC-110 stock solution (mixed at 1:31) and then further cuts it 1:7. I don't have the developing times with me as I'm at work, but if anyone is interested I could give them to you.
He regularly gets way more than 10 zones of printable information on the negative if the scene yields it. Naturally he uses N + or - when needed.
His buddy Don Kirby uses TMAX 100. Rates it at 100asa and develops in Xtol. I also have the times for this as well if you want. Both of them get outstanding negs.
Both of them come from a scientific background and neither of them have any use for densitometers.
If you know what a good negative looks like--like Barnbaum, Kirby, Michael Smith, etc.-- you don't need a densitometer. A densitometer, however, is an excellent tool for someone who is starting out or is trying to learn from a book or who doesn't have examples of good negatives to look at.
Eric, I agree...but both have an idea of what a good negative looks like. I personally rate TriX at 160 as well. Why?, because that is where it exposes at. And to paraphrase John Sexton..."Nothing lives on Zone III".
Originally Posted by EricR