Results Too Dark When Testing Film Speed

Baisao · Sep 22, 2015

I've been testing various films and dev times lately, both for inversion and constant agitation. I'll bracket exposures by stop using a gray card to help me zero in on the best film speed and development time.

One thing I've noticed is that the images that more closely match the gray card have the darkest midtones and little shadow detail, yet highlights look fine. The images that look best for midtones do not match the gray card. I'm a bit stumped how I can get good highlights and shadows but midtones that match the 18% gray card.

Does this indicate that I'm developing for too long?

Here is an example where the gray card matches but the rest of the scene it too dark. This was in full sun on light colored sandstone.

Baisao · Sep 22, 2015

In comparison, this looks more closely like the scene but the card is too light.

Baisao · Sep 22, 2015

APUGuser19 said:
Looks to me like you're underexposing and overdeveloping.

The first shot is 3 stops underexposed, the second shot is metered for the scene and at box speed. Would the second image indicate that it is underexposed and overdeveloped?

bernard_L · Sep 22, 2015

the images that more closely match the gray card

What do you mean??? The gray card is a real object under the sun. The image of the gray card is a more-or-less transparent patch on a negative film. The lighter the real gray card, the darker its image on film: how can they ever match? Or, are you talking about the image on screen X, of a digital conversion by hardware (the "S" word) Y and software Z? Or a real print on silver halide paper grade G, that can be made darker or lighter just changing the exposure time?

Maybe the above sounds unpleasant, but if you think about these issues and try to answer them, you'll have made some progress towards understanding.

Once again. People posting questions "what's wrong with my negative", please don't show a digital posive conversion through an unknown process chain. Please show us a close-up picture (any compact d**l camera or smartphone will do) of the negative held against (but at a distance) a uniform white background.

David Allen · Sep 22, 2015

If you are going to devote time to testing materials you need to use a consistent methodology that fixes appropriate EI for your equipment, chosen film, chosen developer, type of tank, type of agitation, etc.

Your first problem here is that you are using a Kodak 18% grey card. Now at first this may seem like a good idea as it provides a known fixed point of reference. However, an 18% grey card does not, in fact, really give you this information because:

It's reflectance varies a great deal depending upon it's angle to the sun in relationship to the lens.
It is also not truly matt so can also give unreliable results especially when in full sunlight.
Exposure meters are calibrated to 16% grey so you immediately have a discrepancy between what you think you are metering (above variances in reflection from the grey card) plus the difference between the meter's calibration and the nominal 18% value of the grey card.

I have for many years taught students that, whilst boring to do, there is a straight forward testing regime that will fix down all of the variables down in a few hours. Thereafter, the main requirement to move forwards is to expose in a consistent manner and always follow the EI, film/developer development regime (time, temperature, type of tank/tray, agitation, etc) as used during the tests.

You can find the test sequence in this previous post:

(there was a url link here which no longer exists)

Bests,

David.
www.dsallen.de

ic-racer · Sep 22, 2015

How are you determining your (there was a url link here which no longer exists)? Work through this to solve the problem.

As a rule of thumb,

UNDER EXPOSED film prints with midtones too dark (when shadow and highlight are appropriately matched to the printing paper due to toe compression)
SEVERE OVER EXPOSED film prints with midtones too light (when shadow and highlight are appropriately matched to the printing paper due to shoulder compression)

MODERATE OVER EXPOSED film prints fine.

Dali · Sep 22, 2015

Dump the grey card and use your brain. First step: Are shadows areas blocked? Expose more. Second step: Are the highlights blown? Develop less. Third step: As you won't achieve the perfect neg each time, adjust the final contrast under the enlarger with different pape grades / burning and dodging.

Once done, you can then concentrate on the most important: the subject.

RobC · Sep 22, 2015

+1 to what Dali says.

what are you using to do your metering with? In camera average? In camera spot? Hand held incident meter? Hand held spot meter?

I'll assume you are using a spot meter.

Best option is to bin the grey card. A grey card will confuse the situation so forget about grey cards. They are a crutch for the weak of mind which only produce very average results.

Then use half film box ISO so if its a 400 ISO film then use EI 200 speed on camera and on meter.
Then reduce manufacturers recommended development time for ISO Speed (not EI Speed) by 30%. So use 70% of development time.

Then when you meter your subject with your spot meter, pick a shadow area in which you want to just retain full textural detail of that shadow area. Meter that area and the close down 2 stops from what the meter says.

Thats all there is to it. Very simple.

darkosaric · Sep 22, 2015

bernard_L said:
Once again. People posting questions "what's wrong with my negative", please don't show a digital posive conversion through an unknown process chain. Please show us a close-up picture (any compact d**l camera or smartphone will do) of the negative held against (but at a distance) a uniform white background.

Something like this - it is easy visible is this over, under or correct exposed... and you can see markings on the negative, and judge more easily.

Baisao · Sep 22, 2015

David Allen, thank you for pointing out the limited usefulness of a gray card and for the generous amount of time you took to elaborate on your method.

David, Dali, RobC, and ic-racer have collectively helped. Its easy to forget the basics (expose for shadows, develop for highlights) and miss the obvious (were working from the ends of the curve not from the middle out).

So far I dont care for the grain I get from rotary processing but Ill wait until I have my methods dialed in before I make a conclusion.

Baisao · Sep 22, 2015

bernard_L said:
Once again. People posting questions "what's wrong with my negative", please don't show a digital posive conversion through an unknown process chain. Please show us a close-up picture (any compact d**l camera or smartphone will do) of the negative held against (but at a distance) a uniform white background.

This wasn't a question about bromide drag, surge marks, mackie lines, air bells, drying marks, fog, etc. so having a snap of the negative would be of little to no use. The negative edges looked great and there was no adjustment to the scan other than it performed an inversion of the tones and I reduced the size to make it more manageable for the web. If there was something amiss I would have mentioned it. Cheers!

MattKing · Sep 22, 2015

Baisao said:
This wasn't a question about bromide drag, surge marks, mackie lines, air bells, drying marks, fog, etc. so having a snap of the negative would be of little to no use. The negative edges looked great and there was no adjustment to the scan other than it performed an inversion of the tones and I reduced the size to make it more manageable for the web. If there was something amiss I would have mentioned it. Cheers!

Emphasis added by me.

The problem is that scanners and scanning software are not neutral - they impose their own adjustments, whether you want them to, or not. Someone else will get different results from their own scanning environment, even if they are using the same equipment and software.

Which is fine, when you are doing comparisons within your own environment. And very frustrating if someone is trying to help you but not working in that same environment.

pentaxuser · Sep 22, 2015

Baisao said:
So far I dont care for the grain I get from rotary processing but Ill wait until I have my methods dialed in before I make a conclusion.

I don't want to sound like a "dismal Jimmy" but my understanding is that the grain from rotary processing may be very little different from that you will get from inversion.

If I am wrong then no doubt others will say so and if I am then maybe we ought to highlight the fact that grain is less if inversion agitation is used and by how much. If it makes a real difference then it is a major factor in any decision on processing and I am surprised posters haven't make more of this in the past.

pentaxuser

Baisao · Sep 22, 2015

MattKing said:
The problem is that scanners and scanning software are not neutral - they impose their own adjustments, whether you want them to, or not. Someone else will get different results from their own scanning environment, even if they are using the same equipment and software.

Which is fine, when you are doing comparisons within your own environment. And very frustrating if someone is trying to help you but not working in that same environment.

That's interesting. I've never given it much thought but this helps explain differences my buddy sees. We shoot the same film, use the same developer, use the same method (he uses my times), use the same scanner, yet he sees a difference in the scans.

Baisao · Sep 22, 2015

pentaxuser said:
I don't want to sound like a "dismal Jimmy" but my understanding is that the grain from rotary processing may be very little different from that you will get from inversion.

If I am wrong then no doubt others will say so and if I am then maybe we ought to highlight the fact that grain is less if inversion agitation is used and by how much. If it makes a real difference then it is a major factor in any decision on processing and I am surprised posters haven't make more of this in the past.

pentaxuser

Emphasis added.

I am of the same mind. I don't have many rolls under my belt with the Jobo but I haven't been impressed with the grain or highlights, yet can't imagine there would be a significant difference. As I said, I'll give wait to make a judgement. It's good to hear your feedback on this.

pentaxuser · Sep 22, 2015

Baisao said:
I am of the same mind. I don't have many rolls under my belt with the Jobo but I haven't been impressed with the grain or highlights, yet can't imagine there would be a significant difference.

My worry based on what I understood you were hinting at, was that you thought that inversion was going to be a kind of magic bullet held in reserve if rotary processing wasn't giving you the grainless negatives you wanted

I am glad to see that you don't see it as a magic bullet

pentaxuser

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