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

Light, film, exposure..
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Alastair Moore
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So I'm going to start doing some film testing..

Postby Alastair Moore » 06 Nov 2012, 18:53

I've bought some Foma 100 from Blanco Negro up the road and as this is entirely new film for me, I thought it would be a good opportunity to try doing some film testing and get my processes properly figured out. I know there seems to be a two schools of thought - use the manufacturers EI or do your own testing. I've been using the manufacturers EI for all the film I've been using up until now and I think I'm getting pretty good results but I'm sure they can be better. Film has been limited to HP5+, TMax 100 and I had a box of Neopan Quickload when I first started shooting large format.

I plan to stick to shooting one (or two) of three film types - Foma 100 (it's cheap and available up the road and I like what I've seen of other people working with it), HP5+ (it's fast and available) and TMax 100 (I like it!) so planned to buy packs of each of these films and do some testing.

But wow.. is testing expensive! I know you only need to do it once but from what I understand:

- 3 shots manufacturers EI (ISO 100)
- 3 shots at 1 stop above manufacturers EI (ISO 200)
- 3 shots at 1 stop under manufacturers EI (ISO 50)

And then you develop your film at three different times - recommended time, 10% over and 10% under.

Yikes. That's a half a pack of (TMax and Foma 100, and more than a pack of HP5+!) film gone already and I've only been testing. And that's only with one type of developer and one type of film. I've got Rodinal, D-76 and Microphen. I'm only actively using Rodinal because I've not mixed the D-76 or Microphen.

Part of me thinks - pick a developer and a film and stick to it but the other part of me thinks - what might I be missing out on?

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

Postby Ray Heath » 06 Nov 2012, 20:29

So what do you feel is lacking in the negs you've produced so far?
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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Re: So I'm going to start doing some film testing..

Postby Lachlan717 » 06 Nov 2012, 23:35

Have you got a Densitometer handy?

What is the image of?

What controls are in place to ensure consistent lighting?

IMO, if you are going to do some testing, make sure that you know how to do it and what the results mean.

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

Postby Walter Glover » 07 Nov 2012, 05:58

Alastair,

Where did you get your proposed method from? It sounds a bit dodgey to me. For film testing that means something you need an 18% grey card, sunlight and the meter you wish to standardise on.

I'd recommend choosing a film and developer combination based on whatever selection data you are moved by. It might be past experience with the 'LOOK' or it may be price, or availability, or convenience (liquid concentrate as opposed to powder developer) and, for the developer, whether you intend to work one-shot or re-use your developer with replenishment.

Focus the lens you'll be using at infinity (to negate any bellows factor) and then place the grey card into the picture. Set the ISO at the recommended setting and then shoot for Zone V, Zone III and Zone VIII. These are the key Zone that will quickly tell you if you are in the ball park: Zone I indicates the speed of the film, Zone V will indicate mid-tone placement, and Zone VIII indicates where the highlights will be placed in order for them not to blow out.) You could shoot two or three exposures at each Zone bracketing by half a stop and a full stop. Process all the sheets together in one run for the sake of consistency.

Ideally you would have access to a densitometer and read each Zone in a particular exposure set. First up, measure the density of clear film in the rebate (I used to leave the darkslide partially inserted to give yourself a bigger clear film target) and then zero the densitometer on that reading. Then, to determine the speed of the emulsion in the developer you use the Zone I neg should have a density of 0.1 above the reading for the clear film (FB+f = Film Base plus fog). Then read the Zone V neg and the Zone VIII neg.

Zone V needs to be about 0.7 and Zone VIII about 1.2

That briefly sets you on the course for the Zone System of Fred Arch and Ansel Adams. It is a flawed system but it is sort of standard.

I far prefer the BTZS (Beyond The Zone System) method of Phil Davis. I have a spare book of BTZS if you want a loan. Ditto the Adams book "The Negative". There is also the New Zone System by Minor White and Zakia which is more homespun and, as I recall, may dispense with the need for a densitometer.

Let me know if you want to hook-up to borrow the books.
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

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

Postby Walter Glover » 07 Nov 2012, 06:39

Here's another system that looks more like what you stated above. It does away with the Zone V reference.

http://www.zone2tone.co.uk/zone-system-film-testing.htm
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

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

Postby Alastair Moore » 07 Nov 2012, 08:35

Walter Glover wrote:Alastair,

Where did you get your proposed method from? It sounds a bit dodgey to me. For film testing that means something you need an 18% grey card, sunlight and the meter you wish to standardise on.

I'd recommend choosing a film and developer combination based on whatever selection data you are moved by. It might be past experience with the 'LOOK' or it may be price, or availability, or convenience (liquid concentrate as opposed to powder developer) and, for the developer, whether you intend to work one-shot or re-use your developer with replenishment.

Focus the lens you'll be using at infinity (to negate any bellows factor) and then place the grey card into the picture. Set the ISO at the recommended setting and then shoot for Zone V, Zone III and Zone VIII. These are the key Zone that will quickly tell you if you are in the ball park: Zone I indicates the speed of the film, Zone V will indicate mid-tone placement, and Zone VIII indicates where the highlights will be placed in order for them not to blow out.) You could shoot two or three exposures at each Zone bracketing by half a stop and a full stop. Process all the sheets together in one run for the sake of consistency.

Ideally you would have access to a densitometer and read each Zone in a particular exposure set. First up, measure the density of clear film in the rebate (I used to leave the darkslide partially inserted to give yourself a bigger clear film target) and then zero the densitometer on that reading. Then, to determine the speed of the emulsion in the developer you use the Zone I neg should have a density of 0.1 above the reading for the clear film (FB+f = Film Base plus fog). Then read the Zone V neg and the Zone VIII neg.

Zone V needs to be about 0.7 and Zone VIII about 1.2

That briefly sets you on the course for the Zone System of Fred Arch and Ansel Adams. It is a flawed system but it is sort of standard.

I far prefer the BTZS (Beyond The Zone System) method of Phil Davis. I have a spare book of BTZS if you want a loan. Ditto the Adams book "The Negative". There is also the New Zone System by Minor White and Zakia which is more homespun and, as I recall, may dispense with the need for a densitometer.

Let me know if you want to hook-up to borrow the books.


Hi Walter,

I got this testing method from Ken Lee at http://www.kenleegallery.com/html/tech/testing.php. I probably described it incorrectly but I understand the approach he's implying. I've got a Kindle version of the BTZS book which I bought mainly for its reference to incident metering but I'll go and "thumb" through it for information on testing as well and will check out your link too.

Cheers!

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

Postby Alastair Moore » 07 Nov 2012, 08:39

Ray Heath wrote:So what do you feel is lacking in the negs you've produced so far?


To be honest, nothing really but I do find that when I scan them I have to spend a bit too much time in the scanner software getting the scan correct. Now that could just be down to how I've got my scanner set up but am interested to see if I can get a "better" negative.. and what better is, I'll probably not know until I do some testing and either discover I'm good as I am or I get improved negatives (whatever improved might turn out to be)!

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

Postby Walter Glover » 07 Nov 2012, 09:47

Alastair,

You use whatever system you choose but I'd just say that I had a look at the link that you provided and find that his method is almost just empirical testing. You are probably already achieving such indicators in the work that you produce.
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

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

Postby Maris » 07 Nov 2012, 12:31

I do all my film testing on just one sheet of film.

Setting up the camera in front of an evenly lit grey card I place 10 exposures across the film by moving the dark-slide between "clicks". The exposure sequence with respect to "box speed" goes 1/16, 1/8, 1/4, 1/2 1x, 2x, 4x, 8x, 16x, and 32x.

Having set up the usual dev, stop, and fix trays in the darkroom I turn out the lights and cut the sheet of film lengthwise into 4 equal width strips. The strips are thrown simultaneously into the developer and processed with the standard agitation pattern. At intervals a strip is taken out of the developer and placed in the stop bath. Typical intervals are 4, 8, 12, and 16 minutes. After the last strip is "stopped" they all get fixed, washed, and dried. I've got 10 exposures at 1 stop increments and 4 different development times. That's a lot of potential information.

Strip densities are read with a densitometer or photographic spot-meter and the results are plotted like a H&D curve. A bit of arithmetic and interpolation reveals how the film reacts to changing exposure and changing development. The results can be cast in terms of zone system concepts such effective speed alias exposure index alias EI. Contrast expansion and contraction developments, N-1, N, N+1, etc are readable off the density graphs and tables.

After this treatment a film has no secrets left...unless I do something wild like changing developers, altering light metering technique, making long exposures, or using strong colour filters. Then re-testing is in order; another sheet of film to "waste".

Lachlan717
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Re: So I'm going to start doing some film testing..

Postby Lachlan717 » 08 Nov 2012, 16:54

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.

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).

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…

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).

If you don't have an enlarger (and/or a densitometer), you can use this service:http://www.viewcamerastore.com/servlet/the-34/BTZS-Film-Test-4x5/Detail. It is all described at http://www.youtube.com/watch?feature=pl ... LiadimBwmg.

Fred Newman is a great guy. He will help you to find the best process based on your set up (for a smallish fee, of course!!)


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