So this personal EI thing has got me thinking...what about pushing?

So this personal EI test to get well exposed negatives has gotten me thinking.

Let's say I find out that using my preferred film (HP-5+) at 200 ISO is what yields a good negative for me.

What happens when I want to shoot indoors with lower light? (I frequently do)

Normally, I'd shoot HP-5 pushed to 800 or even 1250 and would be happy but technically, I'd have underexposed negatives.

Does the "1/2 box speed + 25% less development time" translate over to pushing also?

In other words...would I:

Shoot at 800, but develop as if I'd shot at 1600 -25% developing time?

I'm just wondering how folks handle this after knowing that they consistently underexposed a certain film at box speed.

If you under expose the film it can be difficult to print. Many printing problems start in the camera. Exposure determines your shadow detail. If your subject matter can do without the shadow detail then under-exposure can work for you.

"Pushing" is a ridiculous term. It is only a term used when underexposing and overdeveloping which means no shadow detail, and a contrasty negative.

ic-racer said:

If you under expose the film it can be difficult to print. Many printing problems start in the camera. Exposure determines your shadow detail. If your subject matter can do without the shadow detail then under-exposure can work for you.

Click to expand...

So...let me ask.
Normally, I've been finding out that based on setting my camera at box speed, I underexpose HP-5+ about a stop, and my negs suffer. So the solution is to preset in an "error factor" that counteracts that by setting my ISO to 200 and thus with my usual exposure method, and usual camera combo...I end up with well exposed negs.

But....what about pushing where you are intentionally underexposing and then over developing?

Is it possible to do the same?

Jim Noel said:

"Pushing" is a ridiculous term. It is only a term used when underexposing and overdeveloping which means no shadow detail, and a contrasty negative.

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Ok, but folks do it and I've had great success with pushing and most definitely retained shadow detail and certainly not over-contrasty negs.
I"m not debating that...I'm asking a specific question and how it relates to the EI question.
Can you shed light on that?

rpavich


the short answer is yes.

the long answer is
you will need to do "tests" just as i described in the other thread of yours.
bracket for the 2 you mention in your OP 800 and 1250.

there used to be a suggestion 30% more development for ever stop underexposed ( and less for over exposed )
you'll have to decide what works for you, your development methods/ agitation methods, your developer/dilution &c.

good luck !
john

silveror0 said:

These two statements seem to be a contradiction. At box speed your negatives "suffer" - in what way do they suffer? Loss of shadow detail? Unacceptable contrast?

Yet when pushing (i.e., reducing exposure with a higher EI) the negatives do not "suffer" and shadow detail is retained with acceptable contrast.

Exposure and development work together to create the desired negative quality. The chosen EI will determine the shadow density; development will determine the contrast to keep the highlights from losing detail in the print. So, assuming no changes in developer or its dilution, you may find that development would need to be reduced when EI is lowered (the opposite of pushing). All this without acceptable grain considerations in small format.

Click to expand...

The third factor is the lighting the photos are photographed under. You may have better luck under "flat" light as opposed to contrasty lighting.

If you decide to adjust development to change contrast, there is no such thing as a single personal EI.

You need different personal EIs for different development adjustments.

One of those EI and development pairs will represent a compromise that gives you the best total results - from shadows, through mid-tones to highlights.

Not just details in those shadows, but how those details render as well.

Most likely, that "best total results" EI nd development pair will be quite close to the film's ISO.

The other EI and development pairs will yield results where either the shadows or the highlights will suffer - at least somewhat. But the pair itself will represent a choice where at least some tones will include details that render well.

So you need to experiment. Rules of thumb may guide you as to where to start your experiments, but not much more.

By the way, you probbly need to do seperate sets of experiments depending on how you present the final product. Darkroom prints vs. transparencies vs scans

silveror0 said:

These two statements seem to be a contradiction. At box speed your negatives "suffer" - in what way do they suffer? Loss of shadow detail? Unacceptable contrast?.

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Under exposed.

Let's go at this from another angle:

Fact 1: Changing developing time will affect film speed. Longer development times result in faster effective film speeds (E.I. = exposure index); shorter times result in a slower E.I. all other things being equal.

Therefore, it is possible that if you are using box speed but underdeveloping you will get underexposed negatives.

Fact 2: The term "pushing" for film exists. It is commonly understood to be, "intentionally underexposing film and adding extra development time to compensate."

The extra development time used in pushing increases the contrast thereby resulting in a more printable negative. It also (according to Fact 1 above) slightly increases the the E.I. of the film, which to a small extent will ameliorate the underexposure. However, the amount of the speed increase is usually in the fractions of a stop faster, and doesn't completely balance out the intentional underexposure. Pushed negatives exhibit loss of shadow detail and increased contrast by definition.

Let's use these facts to answer the OP's questions and analyze the situation:

rpavich said:

Does the "1/2 box speed + 25% less development time" translate over to pushing also?

Click to expand...

First, the answer: No, this is not pushing, by definition (see above).
Qualification: 25% less development than what? Than your time for "normally exposed and well developed negatives"? This is what I would assume you mean and what would result in underexposed and too-thin negatives. To push, you accept the loss of shadow detail and develop enough more to get the highlights to the place they would have been if normally exposed and developed.

rpavich said:

So...let me ask.
Normally, I've been finding out that based on setting my camera at box speed, I underexpose HP-5+ about a stop, and my negs suffer. So the solution is to preset in an "error factor" that counteracts that by setting my ISO to 200 and thus with my usual exposure method, and usual camera combo...I end up with well exposed negs. But....what about pushing where you are intentionally underexposing and then over developing? Is it possible to do the same?

Click to expand...

Not sure what you're asking here: If it's, "is it possible to push film by exposing the film at half of the E.I. that I really want to push it to?" then the question doesn't really make any sense. Pushing is an artificial construct to compensate for underexposure and the resulting loss of overall negative contrast. If you get usable negs by exposing at E.I. 800 and thinking E.I. 1600 at your development time, then, fine, but you're really not thinking about this clearly then.

As for using less than box speed for "normal" negatives, you're in good company. Many do this for a couple of reasons. It builds in a one-stop safety factor for underexposure, it gives a longer-scale negative, it overexposes a bit giving more printable highlights at a too-short development time, etc.

Let's look at this a little closer: When people say to me, "I'm using box speed but my negatives are underexposed" I often recommend exposing more. However, there is also the possibility that the "normal" development time is simply too short. Often just increasing development time solves the problem alone. In other words, the exposure/development system has to be balanced using both variables, exposure to get good shadows, development to get good highlights. Given also that underdevelopment is often mistaken for underexposure and I'm skeptical anytime someone says their negs at box speed are severely underexposed.

Conclusions: Pushing as commonly understood will slightly increase the film's E.I. Underexposing and underdeveloping is not pushing. Pushing is underexposing and developing enough to get printable highlights, which should be more development than needed to get printable highlights for normally exposed negs. What E.I. you use pushing is arbitrary if you get the results you want; it's just an artificial construct to guide you in the right amount of underexposure and overdevelopment to get the results you want. Using less that box speed for "normal" is common because many like the longer-scale negative and/or the look achieved plus the safety factor against underexposure.

Best,

Doremus

Thanks Doremus,
I appreciate the explanation.

Just so you know what I meant, I'll clarify what I said:

What I originally said: "Does the "1/2 box speed + 25% less development time" translate over to pushing also?"

What I meant: "Does lowering the speed chosen + shortening the normal development time translate over to pushing also?"

Example
Box speed of 400
Shot at 200
Should be developed for 15 minutes as if it were shot at 400 (one more stop than 200) but instead developed for 12 minutes (-25% dev time)

Pushed film.
Shot at 800
Should be developed for 25 minutes as if it were shot at 1600 (one more stop than 800) but - 25% dev time = 19 minutes.


Hopefully that was more clear.

rpavich said:

Under exposed.

Click to expand...

If you are getting underexposed negatives, then the most probable cause is wrong metering. Films from all major manufacturers will give nice results if shot at box speed, given correct metering. That said, downrating the film by one stop and pull processing (developing to a lower contrast) might be preferable for many.

EDIT: Underexposure by one stop doesn't require push processing. There will be some quality loss, but nothing terrible. This assumes proper metering...

When using an averaging reflected light meter, a scene of limited brightness range can safely be "underexposed" per the meter reading. If you are using a spot meter or multi-segment metering to determine the lowest scene value for exposure then you already have incorporated this into your exposure.

Michael R 1974 said:

Doremus, be careful with the use of the word "fact". The statement above is only a Zone System construct, due to the nature of the test which targets a fixed density speed point.

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Yes, Michael, I do know that; I was trying to simplify things to aid understanding. And I know that ISO is determined at a specific combination of developer, time, and temperature and that these are invariable and that determination of ISO doesn't even happen at longer or shorter developing times. So I plead guilty to imprecise language; maybe I should have used "given" or "assumed".

Nevertheless, I think it's okay to fib a bit to facilitate the introduction to a concept... And, effective film speed does change with change in development time if we're using any kind of speed point low on the curve to determine that, doesn't it?

rpavich said:

Thanks Doremus,
I appreciate the explanation.

Just so you know what I meant, I'll clarify what I said: What I originally said: "Does the "1/2 box speed + 25% less development time" translate over to pushing also?" ...
Hopefully that was more clear.

Click to expand...

Yep, clearer this time. What you are referring to is known as "pulling" (i.e., the opposite of "pushing") in common parlance. More specifically, pulling is overexposing and underdeveloping (to keep the highlights at about the same place as "normal") as opposed to pushing, which is underexposing and overdeveloping (to keep the highlights in about the same place as "normal"). The former gives you a longer-scale negative with more shadow detail and less separation from low to high, the latter a shorter scale neg with less shadow detail (due to the underexposure) and more separation from low to high.

The use of either pushing or pulling is a practical adjustment made for less than ideal conditions. Pushing for low-light situations when you need a fast shutter speed to hand hold, etc. and pulling to deal with too-contrasty situations. As Michael points out (in rightly taking me to task for imprecise language ) this really has nothing to do with the film's ISO speed. We live with underexposure and make the best of a bad situation when pushing. It has a certain look than many like and for that reason has a life of its own as an expressive approach. Pulling is a down-and-dirty way to get a long-scale neg and tame contrast a bit without taking the time to learn one of the more-complicated exposure and development systems (BZTS, Zone System, etc.).

Just so you know, I'm a Zone System user and never, ever express what I do in terms of "pushing" or "pulling".

Best,

Doremus

Michael R 1974 said:

It's more than being picky on the language. I'm talking about the entire concept of film speed and exposure. Forget about ISO per se. It's the underlying theory that's important. It is rooted in print quality. One of the key points is that the relationship between contrast in the shadows and overall contrast is what determines speed, rather than a target speed point density. As you know, a density on its own tells you nothing. It's the contrast at any given point, and relationships between these gradients that count.

Just as an aside regarding ISO speeds, the standard sets out the sensitometric criteria to be met, but does not specify a developer or development time. That is up to the manufacturer.



Only if you define speed based on a fixed target density irrespective of the overall gradient (ie Zone System).

Again, I'm not trying to change the way people do things, and I'm not arguing against whatever EIs people use. It's just about understanding how the speed on the box is determined, what we're doing when we run our own tests, what the test results tell us etc.

Click to expand...

First time I've used the new post bookmarking system.

rpavich said:

So this personal EI test to get well exposed negatives has gotten me thinking.

Let's say I find out that using my preferred film (HP-5+) at 200 ISO is what yields a good negative for me.

What happens when I want to shoot indoors with lower light? (I frequently do)

Normally, I'd shoot HP-5 pushed to 800 or even 1250 and would be happy but technically, I'd have underexposed negatives.

Does the "1/2 box speed + 25% less development time" translate over to pushing also?

In other words...would I:

Shoot at 800, but develop as if I'd shot at 1600 -25% developing time?

I'm just wondering how folks handle this after knowing that they consistently underexposed a certain film at box speed.

Click to expand...

a proper fil speed/dev test will tell you all of that.

With black and white films, methinks box speed sometimes has a bit of deliberate marketing optimism added to it. Certain film might be marketed as 100 speed, for example, when in fact you really need to use a lower figure like 50 to get cleanly printable shadow gradation. That's why certain popular films are almost never exposed at box speed. It can be a bit deceptive. So you really need to understand where you are placing the shadow values on the characteristic film curve itself, which is never a constant, but varies with type of film, the specific developer, and the combination of
exposure and length of development, which determines the contrast and often alters the curve shape a bit too. Michael hates it when I talk like this,
though I agree with everything he has said here relative to his own analytic point of view. There is no rigid diecast Zone System anywhere in the universe. Not even Stephen Hawkins has one. Everything is relative. That why you shoot, develop the film, print the film as best you can, scratch
your head, and fiddle around some more to decide what needs improving, and what does not. It's right foot, left foot. Do YOU like the results or not?
I could care less whether Minor White is rolling in his grave or not.

"Push" and "pull" are commercial lab terms for tweaking color film development using automated machines. In Zone System talk, "plus", "minus",
and "normal" development are the preferred slang. All this is, is a way to pigeonhole certain shots for a different length of development than other shots, which is perfectly feasible when using sheet film. But with any kind of roll film you have to compromise on something characteristic to the whole roll, or what your priority is. What "push" generally means is that you screwed up and underexposed the shot, and are trying to save what's left. And that is not what "plus" development means at all in Zone lingo. Rather, it means you have indeed given sufficient exposure to shadow values you intend to print, but want more overall contrast into the midtones and highlights due to too flat lighting to begin with, so develop the film longer as needed. This is an oversimplified explanation, of course, but bringing push or pull into black and white film talk just confuses the whole subject.

Michael R 1974 said:

It's more than being picky on the language. I'm talking about the entire concept of film speed and exposure. Forget about ISO per se. It's the underlying theory that's important. It is rooted in print quality. One of the key points is that the relationship between contrast in the shadows and overall contrast is what determines speed, rather than a target speed point density. As you know, a density on its own tells you nothing. It's the contrast at any given point, and relationships between these gradients that count...

Click to expand...

Michael,

I think we're in agreement here in essence. My question to you, if you don't mind bearing with me here, is, doesn't the relationship between shadow contrast and overall contrast change with different development times (I think we agree that it must) and with this, then, won't the effective film speed also change correspondingly?

FWIW (and if you've read my questions to you that other thread about maximum black testing), I don't use a fixed density point to determine my personal E.I., but rather a full range of tones of real-world subjects and "zero in" on an E.I./development combination that gives me good prints. I don't think that's really different from what you suggest, just less precise (in terms of quantification) and purely visual.

So, am I wrong in thinking that effective film speed (defined as what gives me acceptable blacks, shadow detail and highlights in my prints) changes when development time changes? My experience tells me that a significant increase in development time bumps up my effective film speed, i.e., I can expose less and still get achieve the print parameters that define my personal E.I. Just interested in your take on this since you have delved much more deeply into this than I.

Drew,

FWIW, Minor White, from all I can gather, would be applauding, not rolling in his grave!

And, while I tend to use Zone System parlance (normal, expansion, contraction, etc) myself, I used to be closer to the world of small cameras and available-light photography where the compromise of underexposure and overdevelopment to get anything at all to print was a useful if less-than-ideal tool to deal with too-slow film, too-little light, and too-much subject movement coupled with hand-holding. I'm comfortable with using the term "pushing" as a definition for that. The problem for beginners is that they often think don't realize that they are underexposing when "pushing," they just think that more development magically gives faster film...

Best,

Doremus

Well...I thought I'd report back here to wrap this up.

I did a few things yesterday.

1.) I made new "correct" proof sheets for some past negatives that I thought were fine because I noticed that I had printed them with less time than necessary to make sure I could see them. I wanted to see the reality of what I thought at the time were correct exposures.

2.) On the proof sheets that had been actually developed enough to get maximum black, I went back and labeled all of them as to what developer and what time were used. I have them in a proof sheet folder with the proof on one side, and the negatives on the other so when looking at each like that (along with the development details right there) made it much easier to see what was happening.

3.) Based on how those past proof sheets looked and the massive dev chart time as a starting point I spooled a short roll of 20 shots and went out and shot both indoor and outdoor shots at ISO 800.

4.) I cut the roll into 3 pieces and developed them at 3 different times: a.) the recommended time from Massive Dev, b.) +15%, c.) +25%


It was an eye opening experience; very informative.
I also re-learned that the scanner is a liar. Seeing scanned negatives (ones that the scanner density corrects) is incredibly different from seeing them in a contact sheet.

So once I settled on a dev time I printed one of the negatives and immediately noticed how differently they were to print. Much different. I actually had to reduce contrast filter number when printing. Normally I would have had to increase the contrast filter number to get adequate contrast. I also had much longer print times, I had been complaining about my short print times but now I realize that was due to my thin negatives.

I think that the biggest lesson here was the value of sticking to one film, and one developer combination. In looking over my proof sheets I realized how wildly they varied and it was partly due to changing developer and not fully figuring out one film with one developer. I hadn't realized what drastically different results I was getting in each...I was sort of shooting wildly. I will now stick to what I know works.

Now, on to the "box speed" test for today.

Thanks to everyone who helped in this thread.

rpavich,

I think you're really on the right track now. You should reap the benefits of your testing soon in better prints and easier printing.

Doremus

Doremus Scudder said:

rpavich,

I think you're really on the right track now. You should reap the benefits of your testing soon in better prints and easier printing.

Doremus

Click to expand...

It's interesting you say that. I printed two this morning (as opposed to my earlier underexposed negs) and they almost printed themselves. I didn't chase them around at all. I'm not sure how to say it. It was much easier for sure.

Thanks for the help.

ic-racer said:

If you under expose the film it can be difficult to print. Many printing problems start in the camera. Exposure determines your shadow detail. If your subject matter can do without the shadow detail then under-exposure can work for you.

Click to expand...

Cardinal rule. Exposure controls shadow detail. Time in developer highlight density. You can not develop in shadow detail.

Diafine will get a little extra speed ( shadow detail). D76 nothing but extra contrast.