Sanity check on Zone System testing results

After getting a Printalyzer densitometer, I've been going through and re-calibrating all of my favorite film/dev combos.

My process is pretty standard. Load a 4x5 sheet with a slightly modified Stouffer 21-step wedge into my film holder. It has an sticker on it for a true FB+F area on the negative, and a hole punched out for a true zero density reading if needed. Set up the camera at infinity focus, fill the frame with an evenly lit, open-shade white background. Meter background and expose the sheet at Zone X. Develop, read densities for Zone I and Zone VIII. Target density for Zone I is 0.10 over FB+F; target density for Zone VIII is 1.20-1.30.

With HP5+ in HC-110 1:100 dilution, using constant rotary agitation, I found that FB+F was about 0.32 log density. I got expected densities for (N) development by rating at EI 250, and giving 13 minutes and 40 seconds in the developer. All of that sounds basically dead on with what I would expect.

With FP4+ my results are kinda weird. Here's where the sanity check comes in. I exposed at EI 64, and gave only 7 minutes and 0 seconds in the developer (Rodinal 1:100). FB+F came out at only 0.9 log density, and Zone I and Zone VIII came out dead on target for (N). This EI seems about right for Rodinal, but the development time seems very short, and the FB+F is only about 25% of what HP5+ gave me. Mostly it's the short time that seems odd. Massive Dev Chart shows times for FP4+ @ 64 in Rodinal 1:100 of like... 21 minutes, and that's not semi-stand or EMA or anything.

At the end of the day, the densities are, I assume, not lying. Just curious that my times came out so short. I suppose the short time in weak developer could also help explain the extremely low fog.

What do your prints look like. If development time is shorter than expected, that might be ok is your enlarger has a condenser head.

Either way, if you have access to printing paper covering a range of grades, exact development time is not necessary.

Out of curiosity what is your step wedge density for the Zone I test?

If the results are outside of the norm, assume experimental error and repeat the test. Keep a careful watch on the dilution and temperature.

ic-racer said:

Out of curiosity what is your step wedge density for the Zone I test?

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Are you asking because that method generally uses a step tablet density of 2.70 to determine the speed point and the density is too high for the exposure or the exposure is too low to use that density? Depending on how you look at it.

I'm quite certain I followed my normal process correctly in terms of dilution, temperature, agitation, etc. of the developer. I had 200ml of total developer in the tank with the single 4x5 sheet, so 2ml of concentrate - well within published limits on how much concentrate is needed per film.

FWIW, I metered the blank white wall in open shade as very consistently wanting 1/8 of a second at EI 64 and f/7.1. That would be Zone V. Adding 5 stops of exposure to get me to a Zone X exposure meant 4 seconds of exposure time, which after correcting for FP4+ reciprocity failure was 5 seconds, and 5 seconds of exposure is what the film got.

Nominally the #5 step on the wedge should have a density of 0.6 over base (so call it 0.65 total if the average step wedge base density of 0.05 holds), so that would attenuate the Zone X exposure to Zone VIII - the #5 section of the exposed negative is where I took my Zone VIII reading that was right at 1.25 over FB+F.

The #19 step should have a density of 2.7 above the wedge base, so call it 2.75. That corresponds to 9 stops of attenuation from Zone X exposure, so Zone I on the negative. #19 is where I got my 0.12 density above FB+F reading from the negative. A hair over the target 0.10, but not enough to justify going to an EI of 80.

I have not taken actual measurements from the step wedge. I suppose it's possible that I got a particularly bad uncalibrated copy or some such.

Am I getting concerned over nothing here? Anyone else getting normal contrast results from FP4+ in Rodinal 1:100 with constant rotary agitation at 20°C for 7:00? Just seems weirdly short.

Perhaps the best way to confirm my results is just to go shoot, you know, an actual photo, develop accordingly, and see if it prints well at Grade 2.

BHuij said:

I'm quite certain I followed my normal process correctly in terms of dilution, temperature, agitation, etc. of the developer. I had 200ml of total developer in the tank with the single 4x5 sheet, so 2ml of concentrate - well within published limits on how much concentrate is needed per film.

FWIW, I metered the blank white wall in open shade as very consistently wanting 1/8 of a second at EI 64 and f/7.1. That would be Zone V. Adding 5 stops of exposure to get me to a Zone X exposure meant 4 seconds of exposure time, which after correcting for FP4+ reciprocity failure was 5 seconds, and 5 seconds of exposure is what the film got.

Nominally the #5 step on the wedge should have a density of 0.6 over base (so call it 0.65 total if the average step wedge base density of 0.05 holds), so that would attenuate the Zone X exposure to Zone VIII - the #5 section of the exposed negative is where I took my Zone VIII reading that was right at 1.25 over FB+F.

The #19 step should have a density of 2.7 above the wedge base, so call it 2.75. That corresponds to 9 stops of attenuation from Zone X exposure, so Zone I on the negative. #19 is where I got my 0.12 density above FB+F reading from the negative. A hair over the target 0.10, but not enough to justify going to an EI of 80.

I have not taken actual measurements from the step wedge. I suppose it's possible that I got a particularly bad uncalibrated copy or some such.

Am I getting concerned over nothing here? Anyone else getting normal contrast results from FP4+ in Rodinal 1:100 with constant rotary agitation at 20°C for 7:00? Just seems weirdly short.

Perhaps the best way to confirm my results is just to go shoot, you know, an actual photo, develop accordingly, and see if it prints well at Grade 2.

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Sounds like you followed the instructions, Schaefer right? But are the instructions correct? I started to go into a whole discussion on practices and how lacking systems tend to be, but changed my mind. Let's just look at the exposure of this method.

Metered camera exposure will create an exposure of 8/ISO at the film plane. 8/400 = 0.020 lxs.
Open up 5 stops 0.20 * 25 = 0.64 lxs
Exposure at the speed point is 0.80 / ISO = 0.0020 lxs .
Exposure at the step tablet density of 2.70 is lxs.
That's a difference of or almost 2/3 stop.

The tricky point is what the intended constant of the speed equation should be. The ISO constant of 0.80 is to compensate for the blue light of the sensitometer. It reduces the resulting speed by 1/3 stop. If the test was done under more yellow or less blue light, the constant can be considered 1.0. This method (and really almost all) doesn't really state which constant to use. If I'm not mistaken, this method doesn't use a speed equation, it simply says that the step tablet density of 2.70 under the exposure conditions it specifies will give you the EI the test exposure was based off of.

Let's confirm. If a film density of 0.10 was reached at the step tablet density of 2.70 that would be 0.80 / 0.0013 = 615 using 1/0.0013 = 769.
We're basically talking about giving it between about 1/2 to 3/4 stop depending on how the speed is calculated.
For 0.10 to fall at 2.70 would require 1.011 lxs and not 0.64.
For 0.64 to create a density of 0.10 for a 400 speed film, the step tablet density would be 2.50 if using the 0.80 constant and 2.40 if using the 1.0 constant.


This method as defined by Schaefer will generally produce Zone System speeds which are methodologically 2/3 slower than the ISO speeds.

As for your development times, repeat them even if you think you did everything right. If you did, you'll just confirm the results and not have to worry. Although a density range of 1.20 - 1.30 for a grade 2 paper with a diffusion enlarger has a LER of 1.05. Another example of bad practices with a system (Adams, not you).
.

BHuij said:

With FP4+ my results are kinda weird. Here's where the sanity check comes in. I exposed at EI 64, and gave only 7 minutes and 0 seconds in the developer (Rodinal 1:100). FB+F came out at only 0.9 log density, and Zone I and Zone VIII came out dead on target for (N). This EI seems about right for Rodinal, but the development time seems very short, and the FB+F is only about 25% of what HP5+ gave me. Mostly it's the short time that seems odd. Massive Dev Chart shows times for FP4+ @ 64 in Rodinal 1:100 of like... 21 minutes, and that's not semi-stand or EMA or anything.

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If you are developing FP4+ to make sunglasses, then 21 minutes in Rodinal is about right. A time of 7 minutes with constant agitation seems good to me. Trust how your negs look, and be careful with the times you find on the MDC - some of it is wrong.
As for the film base/fog of FP4+, it is so low with the film because it’s engineered to be extremely low. This is why so many people who do alt printing techniques value FP4+ so much! It’s the perfect film for Salt/Platinum/Kallitype printing because of this low base density.

BHuij said:

With FP4+ my results are kinda weird.

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So are the HP5+ negs fine but the FP4+ negs kind of weird?

Thanks

pentaxuser

Whenever I zone system test, I avoid reciprocity territory. Reciprocity testing is done separately. Don't want to deal with too many variables at once.

Both the HP5+ and FP4+ negs look correct to my eyes, and the density readings are what they are. Totally possible I’m getting concerned about nothing here.

I would have avoided reciprocity if I could, but it has been pretty heavily overcast and dim outside here lately, and I was shooting at EI64, so *shrug*

At any rate, thanks all for your responses.

BHuij said:

Both the HP5+ and FP4+ negs look correct to my eyes, and the density readings are what they are. Totally possible I’m getting concerned about nothing here.


At any rate, thanks all for your responses.

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It'd be nice to get to the bottom of what has caused what appears to be weird but in strictly practical terms there is nothing wrong with either development processes?

pentaxuser

BHuij said:

Both the HP5+ and FP4+ negs look correct to my eyes, and the density readings are what they are. Totally possible I’m getting concerned about nothing here.

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I think you're correct. Development times for FP4+ are much shorter than for HP5+ — it's always been that way. I think that if you developed FP4+ rated at 64 ASA for 21 minutes with constant agitation, you would have nearly impossibly dense negatives. Trust your results. If the negs look good, that's your proof.

By the way, I looked at the MDC's listing for FP4+ in Rodinal 1:100 and indeed it states 21 minutes. But that is NOT a time for continuous agitation — that's for intermittent agitation (in a tray). You need to find times for continuous agitation, or you will severely overdevelop your film based on the times listed on MDC.

This info is likely somewhere else within the site. Is the info on the MDC all user derived, or at some point did someone enter manufacturer data sheet information?

AFGA's time for FP4+ (64) in Rodinal 1+100 is 15 minutes for a contrast index of 0.45. Agitation is continuous the first 30 seconds, and then 5 seconds every 30 seconds. 20 minutes is for FP4+ at 125 for a contrast of 0.50.

MTGseattle said:

This info is likely somewhere else within the site. Is the info on the MDC all user derived, or at some point did someone enter manufacturer data sheet information?

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Both. Sometimes you can identify manufacturer data using the notes.

BHuij said:

Adding 5 stops of exposure to get me to a Zone X exposure meant 4 seconds of exposure time, which after correcting for FP4+ reciprocity failure was 5 seconds, and 5 seconds of exposure is what the film got.

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For FP4+, factor is 1.26, which makes a 4 second exposure closer to 6 seconds than 5 when reciprocity failure is factored in — 5,73 to be a bit more precise, and the difficulty in getting this type of precision is the reason why, as Andrew mentioned, reciprocity is best avoided when testing, even if 0.73 seconds doesn't seem very significant.

Alex Benjamin said:

AFGA's time for FP4+ (64) in Rodinal 1+100 is 15 minutes for a contrast index of 0.45. Agitation is continuous the first 30 seconds, and then 5 seconds every 30 seconds. 20 minutes is for FP4+ at 125 for a contrast of 0.50.


View attachment 414150

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I believe Agfa uses gamma γ

Stephen Benskin said:

I believe Agfa uses gamma λ.

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You are absolutely right. My mistake.

Based on the datasheet, normal contrast at 8 minutes is achieved using 1 + 25 dilution. If you get N at 8 minutes with 1 + 100 dilution, it suggests to a potential experimental error. The way to remove doubt is to retest.

All the testing and the discussion is great, but wouldn't it be simpler to just make an exposure of a real-life normal-luminance-range scene and see how the negative prints? Testing is great, but often takes more time and resources than is practical. Making a few actual photographs and then evaluating and adjusting E.I. and development time based on those is often faster.

Have fun,

Doremus

I'd be lying if I said this wasn't mostly a case of "I just got a shiny new densitometer and now everything looks like a nail."

That’s a normal phase to go through and you can learn some interesting things. However it is good advice to test your tests by making pictures and printing along the way otherwise there is the potential to spend a lot of time and/or money lost in density ranges etc. which end up not being ideal for you.

Ultimately if your goal is print quality, it is almost entirely about print controls as opposed to negative “controls”. Making so-called great negatives is very easy / simple. As long as you don’t underexpose, the film takes care of the rest. The control is under the enlarger.

BHuij said:

I'd be lying if I said this wasn't mostly a case of "I just got a shiny new densitometer and now everything looks like a nail."

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The chart Alex posted corresponds with a publication I have from Agfa Canada from the late 90's. It shows a blanket 15 or 20 min in Rodinal 1+100 for almost all Ilford films, 15 min rated 1 stop under box speed and 20 min at box speed.

It has a note that this is in small tanks, with agitation every 30s.

Doremus Scudder said:

All the testing and the discussion is great, but wouldn't it be simpler to just make an exposure of a real-life normal-luminance-range scene and see how the negative prints? Testing is great, but often takes more time and resources than is practical. Making a few actual photographs and then evaluating and adjusting E.I. and development time based on those is often faster.

Have fun,

Doremus

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Precisely!