Testing 4x5 film in 35mm?

I usually test my 35mm film to establish an EI and development time. But now I am starting out in 4x5 and I want to shoot one film to begin with - Arista.edu ultra looks cheap - so I am thinking of getting a couple of hundred sheet boxes and 'learning' that film.

But since my testing procedure is optimized for 35mm, I was thinking if I might just buy a couple of rolls of the same film in 35mm format to do the testing instead of bothering with the tedium of doing the test on 4x5 sheets. I expect film emulsion will be the same across formats, right? One area of concern might be the difference in agitation between a daylight roll film tank and tray development, but do you figure that 15 secs/min will translate across the two processes to maintainreasonable accuracy.

Any thoughts on why I should / shouldn't do this would be helpful.

Thanks,
Anupam

I would test the 4X5 and not rely on the 35mm data. There are too many vairables. Two formats of the same film may not be cut off of the same master roll. Different anti-halation layers can have an affect also. I shoot a lot of Tmx-400 and have different data on 4x5 and 8X10 due to differences in bellows draw and development procedures.

Another thing to remember is that your technique and equipment may differ. If you test with, say, a Nikon F5, you'll be using the F5 meter and the F5 shutter. Assuming that you will get identical results with a handheld meter and your Copal #0 can be a mistake. It's best to test with the equipment you'll be using with that film format, and that requires you to use that format of film.

PhotoJim said:

Another thing to remember is that your technique and equipment may differ. If you test with, say, a Nikon F5, you'll be using the F5 meter and the F5 shutter. Assuming that you will get identical results with a handheld meter and your Copal #0 can be a mistake. It's best to test with the equipment you'll be using with that film format, and that requires you to use that format of film.

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Well, initially at least I intend to use the spot meter on my N90s as a meter and I can use that to shoot the tests, but I guess if the emulsion itself is not quite the same, I need to do it the hard way.

-A

Yes - you do need to do it the old-fashioned way. For starters, the film base is very different between 4x5 and 35mm, which will have a perceptible impact on your film developing and your printing exposures. If you are contact printing, it will make an even bigger difference. You can use the times/temps/ISO ratings from your 35mm as a starting point, but expect deviation. Test to find out what that deviation is.

I agrre with all the other posts. In my experience testing waaaay too many films, format substitution does not work.

Dear Anupam,

With 35mm, the inevitable loss of sharpness and bigger grain that you get with generous exposure is important.

With 4x5, it isn't, and you may well prefer the tonality.

For a starting point, try 1 stop to 2 stops more than works best with 35mm.

Cheers,

R. (www.rogerandfrances.com)

As you mentioned, your differing developing methods will result in a huge difference in agitation. There's no easy way to translate 35mm tank agitation to sheets in trays. But, you could use your 35mm data as a jumping off point for testing sheets.
In my experience, both the Arista.edu films and papers are excellent. Also cheap! Dean

Use your 35mm approach. There is no logic, or merit, in throwing away your experience and knowledge.

The differences between emulsion sizes is minimal, and by choosing ONE emulsion available for all the cameras you use, you can find yourself miles ahead of the 'endless testing' game.

T Max 400 and Xtol is a combination which makes life easy, and lets you shoot 35, 120, and sheets virtually the same.

As for cost, consider how much you have to pay for your leisure time.
Kodak's documentation is splendid.

Actually, using a Nikon F5 for my general testing works very well.

The variations between film sizes is well recorded by Kodak,
and - by exhaustive testing at a very high level of precision -
I learned some time ago that Kodak had done it right.

It is simple to convert results from an F5 test of T Max 400, for instance, to 4x5.

The camera is FAR more accurate than a copal shutter. It is a simple adjustment to compensate for the difference in lens contrast.

The specific adjustments in technique I've made, using reduced agitation and using mid tone density and contrast to evaluate negatives, have made it possible to use a single approach for multiple formats.

> please PM me if you would like to 'flame' this heresy,
and we can discuss it like civilized beings away from the forum ! <

df cardwell said:

The camera is FAR more accurate than a copal shutter.<

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Unless you've figured out a way to put an F5 shutter into a view camera, how does this help?

The inaccuracy of large format shutters is a part of the experience. You have to know how your shutters will perform in order to know how to correctly expose your film. The F5 constantly adjusts its own shutter so that it is always almost perfectly accurate. No mechanical shutter ever made, and particularly not a leaf shutter (because of the very nature of how they work - leaf shutters have efficiency issues that focal plane shutters do not), can come close to that level of accuracy. It doesn't terribly matter, but it does mean that you have to test with your large format shutters to know what you are going to get on your large format film.

It is always a good idea to test a specific film - 35 mm is certainly not the same as 4x5.

One problem when testing 4x5 is that you have to expose a lot of film to get a scale of negative densities. And one way to overcome that problem is to use a number of film holder slides with holes drilled into them.. Each slide can provide two exposures on a piece of film, depending on how it is put in the film holder. I use six slides for twelve exposures - the target is an evenly lit piece of white cardboard - and I expose four sheets of film. Developing could be 4, 7, 11 and 18 minutes - it's easy to pick the films out of the developer one at a time - and the 48 dots can give you all the information you need when measured in a densitometer. The rest is simply a matter of drawing some curves on a piece of paper, and you know all you ever wanted to know about that specific combination of film and developer.

j-fr

www.j-fr.dk

Roger Hicks said:

Dear Anupam,

With 35mm, the inevitable loss of sharpness and bigger grain that you get with generous exposure is important.

With 4x5, it isn't, and you may well prefer the tonality.

For a starting point, try 1 stop to 2 stops more than works best with 35mm.

Cheers,

R. (www.rogerandfrances.com)

Click to expand...

Did you mean let more light through, or use a bigger number?

You have to know how your shutters will perform in order to know how to correctly expose your film.

Of course. Of all the shutters I owned, rented, or just used... or checked on a bench, they tended to be accurate +/- 1/2 to 1 stop. And nearly every one is slower than it is supposed to be.

SO, if you KNOW your film performs relative to a perfect exposure, how hard is it to predict how it will perform over a known variation in a leaf shutter ? It isn't hard.

How is it different than testing film under an enlarger with a step wedge ? Except that the F5 - or any electronic shuttered camera - if available - is easy, and offers feedback that is useful that would involve extra steps otherwise.

Using the F5, with a high quality AF lens gives you a baseline - quickly - that transfers easily to LF methodology.

One can either build a LF technique based on pinpoint exposure that accomodate no visualisation error or performance error, and either gives a theoretically perfect negative or failure, with the statistics siding on the side of failure.

OR, one can use a technique that aims for the middle of the working range of the materials, which gives a high proportion of excellent, if not 'perfect', exposures.

If one is a professional, or just one who values every time he trips the shutter, the second approach should be considered a reasonable -if not ideologically pure alternative to dogmatic LF process.

If one is an LF beginner, with a sound basis in 35mm technique, what is the rationale to throwing out one's knowledge in order to fling himself into the morass of LF tail chasing that afflicts so many beginners ?

Dear Gadget Gainer

Let more light through, either on time or aperture.

Cheers,

R.

I prefer to photograph a Stouffer. This way I get all exposures on one frame.

RalphLambrecht said:

I prefer to photograph a Stouffer. This way I get all exposures on one frame.

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The best method, from the perspestive of time and efficiency, is to photograph a Stouffer transmission step wedge, as Ralph says.

You can do this using BTZS technique, separating testing from the camera system by exposing with an enlarger or sensitometer, or by placing the step wedge in the camera over your film and exposing to a large area that is evenly illuminated (north sky works well for this). Either way you can determine ES of your process, either by printing the developed step wedge and counting steps, or by printing the step wedge and taking reflection readings of the print and plotting the curve. I strongly advise separating your testing from any specific camera and lens system. This may sound counter-intuitive, but in the end it proves more effective in my opinion to establish a standard around generic testing and then adjusting tecnique for know variations in shutters and lenses. This is especially impoertant if you own several camera systems and use each with three or four lenses. What are you going to do? Run Zone tests for every single combination with every film and developer you use? OK, but see you in the 22nd century!

Forget about film speed. Almost all modern emulsions have an EFS speed very close to what is stated by the manufactuerer. That is definitely true of all Kodak and Ilford films. And forget about the claims you hear about some developers delivering a true film speed increase of one stop or more. That is pure BS and anyone who has done a lot of work with sensitometry knows that to be true.

One of the keys to correct exposure is to learn to use your meter, and to adjust EI according to the technique. In much of my own work, for example, I use the BTZS incident method of metering and take my meter reading in open shadows (not the deepest shadows!). For this, I set the ASA to a value about 2X times the rated film speed. There are reasons for this and they are well explained in Davis' Beyond the Zone System. There are other ways to meter with BTZS of course, say in the highlight areas and halving film EI, or by metering in both shadows and highlights and averaging the reading, but either way you *must* know how to set the EI on your meter for the type of metering you do.

As for the original subject of this thread, it is possible to extrapolate a lot of useful data between testing 35mm and sheet film, especially if you are using the same type of film processing. However, attempting to extrapolate between film sizes and different types of agitation procedures should not be done except as a very rough guide to get you into the ball park.


Sandy