Do personal EI's standardize printing times?

ChristopherCoy · May 14, 2021

Andrew O'Neill said:
My goal is to use appropriate EI and development, so that I'll have an easier time printing.

So my question is, how do you know what an appropriate EI is?

Vaughn · May 14, 2021

The easy way is to photograph a typical scene at box speed, then bracket. Develop and pick the best negative (the one that makes prints that one likes, or scans the easiest, or whatever). Check how far from box speed it was -- that is your EI.

Andrew O'Neill · May 14, 2021

ChristopherCoy said:
So my question is, how do you know what an appropriate EI is?

One that gives me ample exposure in the shadows. HP5-PLUS I use EI range from 160 to 320, depending on whether or not I have to give expansion or contraction development.

Andrew O'Neill · May 14, 2021

... My personal EI's are from careful, extensive testing. A densitometre comes in handy, but not necessary. Some piano testers use gadgets, and some use their ear...

grain elevator · May 14, 2021

Consistency in printing comes from consistent metering/exposure. EI is not part of that equation because it remains constant over the whole roll.

ChristopherCoy · May 14, 2021

Andrew O'Neill said:
... My personal EI's are from careful, extensive testing.

Which is what I'm doing now.

ChristopherCoy · May 14, 2021

grain elevator said:
Consistency in printing comes from consistent metering/exposure. EI is not part of that equation because it remains constant over the whole roll.

What does "consistent metering" mean? I always use the TTL meters with my 35mm's. The F2's are center weighted of course, and the F5 is set to spot. When I meter, I point the center spot at my subj and get a reading. If it's a middle tone I leave it, if it's a part of the image that should be brighter I'll drop the shutter speed a stop or two, and if it should be darker I'll increase it a stop or two.

DREW WILEY · May 14, 2021

Fred Picker's doctrinaire method was an ideological straightjacket. I doubt even he ever stuck to it. The whole point is to attain a VERSATILE negative with as much desired luminance range from the scene being present in the negative itself to allow some flexibility in printing. Anyone who goes around stating they're going to bag exactly this or that specific density in the print itself based on a personal EI for Zone V if bluffing. Papers change. Maybe our first notion of the "previsualized" outcome (in their vocabulary) changes in route. It's not a mechanical thing.

Yes, back when graded papers were predominant, it was wise to target the negative to the parameters of a chosen brand and grade of paper. I personally standardized on Grade 3 of several papers, all of which differed somewhat in actual contrast characteristics. And of course, it was feasible to switch to other grades if necessary, harder or softer. Now we've got the convenience of really good VC papers. Old negs which were hell to print back then are often easy to do now, especially if they were made prior to when I understood this kind of topic. But I approach every single shot as a its own distinct problem. I use a number of film, and know when to cut the box speed and when I don't need to, even with the very same film. No hard rules, just an understanding of what strategy to apply, exactly when and why.

For example, high contrast scenes present different challenges than low contrast ones. A calm day versus a windy day can affect such choices also, especially if I don't have a fast film along. It would all be hopeless today anyway - cold ocean wind outright howling outside, more like a typical June afternoon here rather than May. I drove up the canyon where it's usually calmer, and drove right back. Maybe tomorrow.

Bill Burk · May 14, 2021

ChristopherCoy said:
If you go through the trouble of the film speed test, and the film development test, do your printing times become standardized?

For instance, if your predetermined exposure of 15 seconds gives you zone I and zone VIII, and nothing changes, can you always just stick any negative in the enlarger for 15 seconds as a starting point and get the full range of print values, or do you still have to do the test strip thing?

You CAN change your printing times by changing your EI.

Typical developing contrast is roughly 0.5 to 0.6 (a half). This simply means if you quadruple your exposure, you double the printing time.

So if you shoot 100 film at EI 100 and get 16 seconds print time, you can set the EI to 25 and get a 32 seconds print time.

This is a great illustration of the idea of a personal exposure index. But even though I delight in explaining “this is as good a reason as any” to base an exposure index... I don’t think it is practical or wise. Neutral density filters at the enlarger achieve the same result without the trade off of speed, grain or image quality.

Your ability to hold a standard print time depends on your ability to control other factors such as subject contrast and development time.

But you could easily decide you want a certain print time and adjust your EI to get close to it.

ChristopherCoy · May 14, 2021

Bill Burk said:
Neutral density filters at the enlarger achieve the same result without the trade off of speed, grain or image quality.

Dear God that's brilliant! I've never even thought about that.

MattKing · May 14, 2021

If the process of finding a personal EI results in your ending up with more consistently exposed negatives, then you will most likely find that printing will be more consistent as well.

DREW WILEY · May 14, 2021

Christopher, TTL metering works better for color film than black and white; but even with color I strongly prefer hand-held meters. There's no intervening complication in between the light and the actual meter mechanism. In black and white work, you especially want to be able to accurately compare where the highlights are going to fall in the exposure versus the shadow values, potentially over quite a contrast range. With most color films, if you drift too far from the midpoint exposure, colors themselves with shift, and not just densities. Two different games.

BrianShaw · May 14, 2021

Vaughn said:
The easy way is to photograph a typical scene at box speed, then bracket. Develop and pick the best negative (the one that makes prints that one likes, or scans the easiest, or whatever). Check how far from box speed it was -- that is your EI.

LOL... it really is this easy and always has been!

ChristopherCoy · May 14, 2021

DREW WILEY said:
Christopher, TTL metering works better for color film than black and white; but even with color I strongly prefer hand-held meters.

I've tried hand held metering, really I have. I have a Sekonic L-408 or whatever it is, with the 5° spot. My issue is that when I shoot with the 35mm's I hate juggling the cameras, and the light meter, and actually stopping long enough to do it. The stopping part is probably the hardest part of it all. I mean, when I'm typically shooting the 35mm's I'm not out doing some grand architectural shots, or adams-esque landscapes. I'm walking around and acting more like a squirrel hunting nuts. But then I guess the old saying, you get what you pay for comes into play. If I only spend 30 seconds on a shot, then I'll only have 30 seconds worth of quality in the print.

MattKing · May 14, 2021

ChristopherCoy said:
If I only spend 30 seconds on a shot, then I'll only have 30 seconds worth of quality in the print.

Not accurate.
The quality of the results is a logarithmic function, with an asymptotic nature .

Bill Burk · May 14, 2021

ChristopherCoy said:
Dear God that's brilliant! I've never even thought about that.

Kodak No.96 0.60 is the best! 2 stops is not too hard to focus and see the easel for dodging. Just drop it inside the enlarger on top of the enlarging lens.

ChristopherCoy · May 14, 2021

MattKing said:
Not accurate.
The quality of the results is a logarithmic function, with an asymptotic nature .

Big crayons Matt.... big crayons.

Paul Howell · May 14, 2021

Vaughn said:
The easy way is to photograph a typical scene at box speed, then bracket. Develop and pick the best negative (the one that makes prints that one likes, or scans the easiest, or whatever). Check how far from box speed it was -- that is your EI.

I agree, wish I had said it, unless you are shooting zone, the whole zone system not just bits of it, bracket, pick what you like, in a well exposed negative you should see detail in the shadows, read new print through the highlights.

BrianShaw · May 14, 2021

ChristopherCoy said:
If I only spend 30 seconds on a shot, then I'll only have 30 seconds worth of quality in the print.

Nope. Incorrect. I think you’ll someday realize that your TTL exposure is right 99.x% of the time. You don’t have to be a slave to complex exposure determination unless the scene is rather complex or unusual. In other words, the exceptions to normalcy are exceptions rather than the norm.

DREW WILEY · May 14, 2021

Brian - bracketing? What if the lighting suddenly changes, or the wind? What if shooting a few more redundant sheets of 8X10 film each time you go out means you have to re-mortgage the house? Statistical probability? - I trust myself to evaluate the meter results far more than any built-in camera program. Those things don't think; they're rote. I don't want a machine making esthetic decisions for me.

Bill - what the heck is "standard printing time"? Do you still use an hourglass? We have clocks here. Yeah .... it's really a big headache to reach over and spend an extra two seconds resetting the enlarger timer. That's just about the worst reason I've ever heard for tweaking an EI. It's also nonsense densitometry. Are you the next Fred Picker?

BrianShaw · May 14, 2021

DREW WILEY said:
Brain - bracketing? What if the lighting suddenly changes, or the wind? What if shooting a few more redundant sheets of 8X10 film each time you go out means you have to re-mortgage the house?

LF is often an exception regarding the ease of a bracketing method. I agree.

For LF I’d revise what I said and assign a different percentage. Maybe 98.x % of the time a general coverage reflected reading or an incident reading is sufficient to get a reasonable exposure.

ChristopherCoy · May 14, 2021

BrianShaw said:
Nope. Incorrect. I think you’ll someday realize that your TTL exposure is right 99.x% of the time. You don’t have to be a slave to complex exposure determination unless the scene is rather complex or unusual. In other words, the exceptions to normalcy are exceptions rather than the norm.

Honestly, I haven't noticed that many detours from correct exposure to tell you the truth, especially in the rolls from the last couple of months. Most of my contact sheets are satisfactory for me. But I would still like to at least test and determine my personal development time. Thus far I've only used times and recipes that I've either found in forum posts, or on the MD site.

MattKing · May 14, 2021

ChristopherCoy said:
Big crayons Matt.... big crayons.

Where is the fun in that?
Here is an example of a picture:

The vertical axis is quality, the horizontal axis is time spent, and the dotted line represents excellence.
The large dip in the middle is where you are spending time over-thinking things!
Note that as you move toward the right, and add more time, you are getting closer and closer to excellence, but you never get there completely (that is the asymptote).
The curve is probably not logarithmic, but it looks sort of similar, and I couldn't find what I needed quickly .

wiltw · May 14, 2021

Before everyone gets so esoteric and off on tangents arguing about personal EI and its derivation, I would like to bring EVERYONE back to the OP question!:

Is is possible to make a 'standard' exposure on film, and be able to print that standard exposure in the darkroom at a standare TIME, rather than a different print time for each print?

BrianShaw · May 14, 2021

I understand what you want. Testing will either validate you current methodology or give you information to make changes. I must be lazy because when my work looks “good enough” I give composition and subject matter more attention rather than trying to make good enough perfect. But I respect both ways.

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