So I'm going to start doing some film testing..

Light, film, exposure..
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RoganJosh
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Re: So I'm going to start doing some film testing..

Postby RoganJosh » 08 Nov 2012, 17:53

Does anyone else find film testing somewhat useless unless your gonna be printing chemically? There is so much dynamic range leeway with modern films that you can afford to raise those shadows an extra 2/3 of a stop to account for box speed inconsistencies. I also find myself using contraction/expansion less and less now that photoshop can control the shadows, midtones and highlights individually and with such precision. Don't get me wrong, I think any serious photographer should know and use the zone system but there is no need to adhere so strictly to it anymore.

As long as I know the film is going to hold the information I need, why waste time tinkering that is better spent behind the camera.

Lachlan717
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Joined: 03 Aug 2012, 16:49

Re: So I'm going to start doing some film testing..

Postby Lachlan717 » 08 Nov 2012, 18:16

RoganJosh wrote:Does anyone else find film testing somewhat useless unless your gonna be printing chemically? There is so much dynamic range leeway with modern films that you can afford to raise those shadows an extra 2/3 of a stop to account for box speed inconsistencies. I also find myself using contraction/expansion less and less now that photoshop can control the shadows, midtones and highlights individually and with such precision. Don't get me wrong, I think any serious photographer should know and use the zone system but there is no need to adhere so strictly to it anymore.

As long as I know the film is going to hold the information I need, why waste time tinkering that is better spent behind the camera.


Of course you don't need to test film.

However, I disagree that PS is a panacea for poor exposure. You can only get what is on the piece of film. If you don't have shadow detail, PS will just show slabs of black. If you blow out highlights, there is no saving them in PS.

Once you have tested the film, there is nothing extra to do. It is a once-off "payment". Once you know it, you simply meter to it. No difference in effort. You have to process the film regardless, so why not expand/contract it? If it's contraction, it actually takes less time/effort!

I want the best possible negative that I can get, so I test film and process accordingly. YMMV.

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RoganJosh
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Re: So I'm going to start doing some film testing..

Postby RoganJosh » 09 Nov 2012, 11:36

However, I disagree that PS is a panacea for poor exposure.


This is true, i'm just saying that there is far less harm in not testing film than there used to be. I've been placing my shadows slightly higher than I used to to account for box speed discrepancies and i've never had trouble with blowing out the highlights in my negatives...it's actually kind of hard to do with films like t-max.

I also agree that contraction is still an important process, but expansion far less so. If you build up highlight density too much through development it's something you can't come back from in PS, whereas if you develop normally you have more useable info to play with.

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Maris
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Re: So I'm going to start doing some film testing..

Postby Maris » 09 Nov 2012, 18:05

Lachlan717 wrote:
Maris wrote:The exposure sequence with respect to "box speed" goes 1/16, 1/8, 1/4, 1/2 1x, 2x, 4x, 8x, 16x, and 32x….
I've got 10 exposures at 1 stop increments...

It seems to me that, if you don't start with a repeated time, you will not have an accurate 10-stop range; it will be just over 11 stops (1025/16th to be exact).
With the spread that you gave, you would need to run the shots as 1/16, 1/16, 1/8, 1/4 etc. As you have detailed it, the first exposure will be 1/16, the second will be 3/16 (rather than the required 2/16), the third on 7/16 (not the 4/16 needed), the forth 15/16 (not the 8/16) and so on down to a 32 second exposure being a cumulative total of 1025/16th (64 1/16th seconds). You need to factor in the cumulative aspect of multiple exposure, meaning that you will be about a stop out per "band" after the initial 1/16th one.

You are absolutely correct that the shutter speed/f-stop setting is repeated for the second exposure otherwise the doubling sequence doesn't come out right. It is what I do.
Also, I doubt that running shots past 1 second will be of much value for working out EI for most films due to reciprocity failure skewing results. It is fine once you have EI worked out, but only to ascertain reciprocity compensation for a given EI. You would be best served by shooting the first two "bands" of film at your fastest available shutter speed (light permitting).

I try not to go past 1 second but more from concerns about lack of consistency in manually timed exposures compared to mechanical timing rather than worries about reciprocity failure. For daylight exposures the problem doesn't really come up. For example 32x times Zone V exposure for a 100 speed film comes out at about 1/2sec@ f16. Actual testing of reciprocity failure is a tedious business but my results indicate that the film manufacturer's tables are often madly pessimistic. I suspect film makers don't bother to test but offer generic tables with a big "safety" margin thrown in.
It would also be very useful to have a calibration of shutter speeds done prior to doing any testing in order to know if you are actually giving the exposure at the stated shutter speed…


Yes, I have a millisecond resolution shutter tester and actual shutter speeds are known and allowed for. And you are right about the imperative to do this for sensible results.
If you have an enlarger, a simpler and more accurate process would be to flash a piece of the test film with a Step Wedge over it (see http://www.viewcamerastore.com/servlet/ ... ion/Detail).
[/quote]
Laboratory style film testing is best done with step wedges but I've convinced myself that results I get by in-camera exposures translate better to actual shooting conditions because lens flare and camera-body flare are automatically incorporated in the results. Both paths to knowledge work but mine, I reckon, is quicker if dirtier.

Walter Glover
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Re: So I'm going to start doing some film testing..

Postby Walter Glover » 10 Nov 2012, 09:48

Before you can really do any meaningful testing you need to know what it is that you want to do with your negs.

If you want to scan them and show them on the internet and possibly do ink-jet prints then, as already suggested, there is a lesser requirement for precision (perhaps).

If you want to print them with an enlarger on silver paper then matters become quite stringent.

Although I only scan at present, it is my intention (hope) that I will press the Durst into action in the not-too-distant. I apply the results of the BTZS testing I did years ago in the sure and certain hope that all will be well.
Walter Glover

"Photography was not a bastard left by science on the doorstep of art, but a legitimate child of the Western pictorial tradition." —Robert Galassi

Ray Heath
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Joined: 15 Oct 2012, 13:21
Location: Lower Hunter Valley, NSW

Re: So I'm going to start doing some film testing..

Postby Ray Heath » 10 Nov 2012, 16:02

G'day all

Alastair, I wonder if all this film testing is worth it, especially when done "scientifically". I accept there are many variations in exposing, processing, printing,aesthetics etc but really, how much better do you think you can get your negs than if you follow the advice given by the experts who made the materials.

I was convinced many years ago that because film is not made or tested for Aussie lighting conditions then I should at least half or three quarter the ISO and use the normal processing times. This I did and produced hundreds of rolls of, I think, perfectly exposed and easily printable 35mm negs over 25years. No testing, no wedges, no densi thingo, just they look good and print really well.

Newcastle-LooGhost.jpg
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Ray

Frank Meadow Sutcliffe's photographs are "a bridge that spans the widening gulf of time" (Michael Hiley 1979, 5).

Lachlan717
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Joined: 03 Aug 2012, 16:49

Re: So I'm going to start doing some film testing..

Postby Lachlan717 » 10 Nov 2012, 20:17

IMO, expansion/contraction isn't really applicable to roll film.

Andrew Nichols
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Joined: 11 Dec 2012, 17:19

Re: So I'm going to start doing some film testing..

Postby Andrew Nichols » 11 Dec 2012, 22:02

Chris from blanco recommends iso 64 for fomapan.


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