Zone VIII confusion

[SoulSurround]

Dear film-testers,

I always understood that development-time affects the higher zones (VIII) and exposure the lower zones (II). Now I have the following story:

I am testing in FP4 (35mm) film for flash photography. On one roll (24 exposures) I exposed zones II, V and VIII (using a greycard) for both ISO 64 and ISO 50.

This roll was developed and the result was that at 64 ISO zones V and VIII were spot on but II was slightly off (not dense enough). The weird thing is that at 50 ISO zone II was spot on... but zone VIII had become less dense!

As all exposures were on the same roll and hence developed for the same time, I wonder why the highlights differ?! I thought they should not differ a lot as development-time is the factor that influences the highlights. Does it have something to do with flash photography?

All comments are very welcome!
Jeroen

 

[Maine-iac]

Dear film-testers,

I always understood that development-time affects the higher zones (VIII) and exposure the lower zones (II). Now I have the following story:

I am testing in FP4 (35mm) film for flash photography. On one roll (24 exposures) I exposed zones II, V and VIII (using a greycard) for both ISO 64 and ISO 50.

This roll was developed and the result was that at 64 ISO zones V and VIII were spot on but II was slightly off (not dense enough). The weird thing is that at 50 ISO zone II was spot on... but zone VIII had become less dense!

As all exposures were on the same roll and hence developed for the same time, I wonder why the highlights differ?! I thought they should not differ a lot as development-time is the factor that influences the highlights. Does it have something to do with flash photography?

All comments are very welcome!
Jeroen

Are you judging density by eye or by densitometer?

A few possibilities come to mind:
One, given the vagaries of shutter performance in most cameras, the difference between ISO 64 and ISO 50 in a film like FP4, which is a very forgiving film to begin with, is not going to be very noticeable. That's less than half a stop.

Two, if these were indeed flash photos, then you've introduced a whole new element into the test. Flash capacitors vary in efficiency; perhaps the capacitor was not fully recharged between flashes, so that you actually gave the film less exposure on the shot you thought you were giving either the same or more exposures.

Three, film itself varies from roll to roll and from emulsion batch to emulsion batch, as does position in the developing tank which could account for the difference, especially when the two ISO's were so close.

Larry

 

[Claire Senft]

It indicates to me that you should use approx 80 as a film speed and increase development time, Altenately you can change development procedures so that the low zones get increase in density with the high zones recieving less contrast increase. One way to do this is with developer dilution. Another way could be stand development. A third and perhaps the most promising would be divided development.

I am uncertain of your methodology. I get the impression that you are trying to match the presribed density offered by others as being ideal. I would opine that each case is unique. You are using your enlarger with its light source with your enlarging lens and choice of paper. I think that to arrive at a good and pleasing result you will have to make some prints. There are at least 4 factors involved: film, film development, paper choice and most importantly what you like for print values. For a given negative printing on a different paper can make a substantial difference in print appearance.

All of this is fine and well. Keep improving your technique. For 35mm to be used with the zone system you need to develop each scene individually. The way I accomplish it is to bulk load 6 frame rolls and expose and develop each seperately.

Go get em!

 

[SoulSurround]

Are you judging density by eye or by densitometer?

I use the Heiland Splitgrade as a densitomer

One, given the vagaries of shutter performance in most cameras, the difference between ISO 64 and ISO 50 in a film like FP4, which is a very forgiving film to begin with, is not going to be very noticeable. That's less than half a stop.

The electronic shutter in my Canon EOS3 is quite reliable, especially since I bracketed around zone II (I could see the densities "grow").

Two, if these were indeed flash photos, then you've introduced a whole new element into the test. Flash capacitors vary in efficiency; perhaps the capacitor was not fully recharged between flashes, so that you actually gave the film less exposure on the shot you thought you were giving either the same or more exposures.

True, however I always check that the indicator of my flash indicated that it is fully charged. But once again... the densities in the bracketed series build up as I would expect.

Three, film itself varies from roll to roll and from emulsion batch to emulsion batch, as does position in the developing tank which could account for the difference, especially when the two ISO's were so close.

POSITION IN THE DEVELOPING TANK... ghee, I am now wondering why I am trying so hard. Maybe I should just start shooting some portraits instead of my greycard and see if I like them...

Nonetheless, thanks Larry, appreciate it!

 

[SoulSurround]

I get the impression that you are trying to match the presribed density offered by others as being ideal.

You got the exact right impression... I now see I am a neurotic man :-(. As my FP4-process should be OK-ish with the current results I should spend my time indeed on doing some photography and adjusting my process according to my preference...

Thanks Claire... sometimes it takes a woman.
Jeroen

 

[smieglitz]

Flash photography can introduce some variables. First is reciprocity failure due to the short duration of the flash. You usually need to extend development to compensate flash exposures. Second, if doing multiple pops to arrive at the high zone exposures, you introduce an intermittence effect and multiply any equipment errors as others have suggested.

Joe

 

[SoulSurround]

Flash photography can introduce some variables. First is reciprocity failure due to the short duration of the flash. You usually need to extend development to compensate flash exposures. Second, if doing multiple pops to arrive at the high zone exposures, you introduce an intermittence effect and multiply any equipment errors as others have suggested.

Joe

Yeah, that is indeed in accordance to the results I have for my TRI-X film; flash is developed a bit longer than 'daylight' exposures. Also - for tri-x - I have to rate my film 1/3 lower (200ISO instead of 250).
By the way, for this test I used a 550EX Canon speedlite (on the manual setting) which pops once for an exposure.

I guess I have to:
1) Redo the test to be sure.
and/or 2) start taking some pictures and see whether I like the current results.

Thanks everybody,
Jeroen

 

[Donald Miller]

I think that, in my experience, it is highly difficult to assign a tonal value in a print when one is making flash exposures without a flash meter.

Second, I don't hear you making a density value assesment of the lower zones.

Third the best criteria is to not try for a targeted high value density alone...it is best to strive for a density range on the camera negative. Normally for silver printing this is approximately 1.00. If you try for a 1.35 Zone VIII density and you have a .45 shadow value density then you will not have the optimum density range.

Finally high value density is affected by exposure and development...not development alone.

I recently encountered a fellow that was doing a lot of testing and ended up underexposing film by at least two stops and was compensating by decreasing developer dilution (increasing strength). It was a method that I would not choose for myself and speaks to the need to be sure that tests are done accurately.

 

[SoulSurround]

I think that, in my experience, it is highly difficult to assign a tonal value in a print when one is making flash exposures without a flash meter.

Who said I didn't use a flash meter? I have a Seconic that spot-flash-meter, that I use to meter the graycard I 'flash'.

Second, I don't hear you making a density value assesment of the lower zones.

I do assess the lower zones (II).

I will post my density values this evening when I get home from work. This will make things clearer... well not for me, but maybe for you ;-).
Jeroen

 

[Nick Zentena]

Some/Many camera flashes light the ready light at 80% or so. It's good enough for most things and it lets you shoot a little quicker. Unless you're sure your flash waits until 100% to light the indicator wait a while longer.

 

[Paddy]

for this test I used a 550EX Canon speedlite (on the manual setting) which pops once for an exposure.

Let's back this up a bit. First, there's the issue of using a strobe for film testing, which I never use or recommend, for reasons addressed above.

Second, regardless of light source used, how is the light positioned? On camera? Never! Why,...because the angle of incidence is very high, and this will result in glare off the grey card. Or if it's off camera, then with only one light you will not be able to acheive even lighting of the card. A densitometer will always reveal these subtle (to the eye) differences. The method I recommend is to use 2 duration blue photo-floods (daylight balanced) positioned perfectly at 45 deg. angles to the grey card. (the same as when doing copy work)

A requirment when performing these (rather dry) tests is to be stringently consistent. We want to eliminate as many variables as possible. Strobe is a variable. Daylight balanced duration light is quite consistent, and as a result, it becomes easy to detect an inconsistency like a worn shutter, etc.

A variant, is to place your grey card on the north side of a building, in open shade (no overhanging tree shade, etc) at high noon on a clear day.

Third, I'm wondering why you've used Zone II to establish your threshold exposure (.10 above FB+F). Zone I is usually used for this purpose. This echoes what Donald Miller touched on above.

If one doesn't use a densitometer, then a visual assessment of The Zone I exposure on a contact sheet printed at "proper proof/standard contact time", will provide a fairly accurate indicator of film speed.

 

[SoulSurround]

Some/Many camera flashes light the ready light at 80% or so. It's good enough for most things and it lets you shoot a little quicker. Unless you're sure your flash waits until 100% to light the indicator wait a while longer.

Thanks for the tip... will do so next test!

 

[SoulSurround]

Let's back this up a bit. First, there's the issue of using a strobe for film testing, which I never use or recommend, for reasons addressed above.

Well as I work a lot with strobes, and as a fact film speed & development-times really do differ with strobe lighting. Hence there is no choice as to test with a strobe.

Second, regardless of light source used, how is the light positioned?

I use one strobe reflected off an umbrella positioned well above the camera. I checked for even lighting on the total surface of the greycard (middle and all corners) to make sure I got the same reading on all spots

A requirment when performing these (rather dry) tests is to be stringently consistent.

I understand, however this was not "between rolls" it was the same session with bracketed series on the same roll (I just varied the ISO speed from 64 to 50 in the two series... nothing else changed)

For the record, here are the densities I found:

64ISO:
II= 0.18
V= 0.71
VIII= 1.28

50ISO:
II=0.24
V=0.70
VIII=1.15

Third, I'm wondering why you've used Zone II to establish your threshold exposure (.10 above FB+F). Zone I is usually used for this purpose. This echoes what Donald Miller touched on above.

Well that is because I am more interested in zone II than zone I. You could argue this... however, if Zone I =0.10 then Zone II falls on 0.24 for a diffusion enlarger.

If one doesn't use a densitometer, then a visual assessment of The Zone I exposure on a contact sheet printed at "proper proof/standard contact time", will provide a fairly accurate indicator of film speed.

I will keep the tip in mind, however so far the Splitgrade proved to deliver accurate results (I compared them with another densitometer and they were practically spot on).

My question remains though; can anyone explain my last value (in red), considering that the development-time was the same. So far: differences within the development-tank is the only option that explains it I think... or the not fully loaded flash (however, the results from the bracketed serie kind-of rule that option out).
Thanks for all your responses so far!
Jeroen

 

[Paddy]

Well that is because I am more interested in zone II than zone I. You could argue this... however, if Zone I =0.10 then Zone II falls on 0.24 for a diffusion enlarger.

While it may be a small difference, I feel that it's important. Zone I has that much less exposed silver than Z.II, and therefore will be less subject to drifting with development changes, esp. when trying to dial in e.i./dev. time. i.e. it's an ever so slightly more stable target for speed testing.

After all, you're trying to address an equally small, but niggling drift in Z. VIII density. I'd be tempted to say that natural shutter variation is the cause of the unexpected number. I've seen the same with my very new quartz controlled shutter. Some speed settings just don't prove as consistent/calibrated as others. Repeated tests of those speed/aperture combos will usually bear this out.

 

[Donald Miller]

Well that is because I am more interested in zone II than zone I. You could argue this... however, if Zone I =0.10 then Zone II falls on 0.24 for a diffusion enlarger.

You are making an error in reasoning in your calculations as noted above. In assigning a .14 or .15 density gain between "zones" in the lower values you are failing to recognize and acknowledge the characteristics of the film. Some films may only change by one half of the value that you think in that region...sometimes even less.

My suggestion would be that you go back and reread the material on the Zone System. It may pay you dividends.

Beyond that the speed point of a film is not a static value. It will vary with development. Density derived in changing exposure and hence development in relation to exposure will change with changes in either or both of these variables.

 

[SoulSurround]

Thanks!

My suggestion would be that you go back and reread the material on the Zone System. It may pay you dividends.

Point taken, however "Way Beyond Monochrome" is my "handbook" and they are a bit more practical than Ansel. Like a wize woman said before, I am going to focus on making nice photo's again instead of following the math. I guess I have come to the point that doing more mind-numbing tests will really take the fun out of photography for me... maybe I'll pick it up later again.

Thanks for all the good advise!
Jeroen

 

[L Gebhardt]

My method after lots of testing has come back to: figure out your film speed (zone I exposure); develop about the right amount; print on VC paper. I really haven't seen any quality difference between my images that work well at grade 2 or grade 3, so I aim for that region. This came about once I purchased a Jobo and decided I had better things to do than develop each sheet individually.

It sounds like you have the speed and aproximate dev time figured out, so as you said go take some pictures.