BTZS Testing?

I'm about to send off some EFKE PL100 to the View Camera Store to begin the process of being tested via Phil Davis's BTZS system.

At the same time I plan on ordering his book, DVD and Power Dial. Is there anything I'm leaving out that would also be helpful? I've already been to his informative web site.

Mike A

Just make sure that you take notes on exactly how you develop the film, including developer, dilution, time, temperature, and nature of the agitation. The usefullness of the data supplied to you by the View Camera Store from their testing depends on you following the same procedures in the future.

Personally I would wait to read the book and Davis' explanation of the testing procedures before doing the testing unless you already have a clear idea of how this is done.

Sandy

Mike A said:

I'm about to send off some EFKE PL100 to the View Camera Store to begin the process of being tested via Phil Davis's BTZS system.

At the same time I plan on ordering his book, DVD and Power Dial. Is there anything I'm leaving out that would also be helpful? I've already been to his informative web site.

Mike A

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Thanks Sandy,
I think I'll do just that, I have allot of questions in my head right now regarding the whole process. I think the book will help answer some of them and give me a little better understanding of Davis' system.

Mike A

sanking said:

Just make sure that you take notes on exactly how you develop the film, including developer, dilution, time, temperature, and nature of the agitation. The usefullness of the data supplied to you by the View Camera Store from their testing depends on you following the same procedures in the future.

Personally I would wait to read the book and Davis' explanation of the testing procedures before doing the testing unless you already have a clear idea of how this is done.

Sandy

Click to expand...

You say you are about to send the film in. Is this pre exposed film that they sent you to develope? If not contact them on getting some PL 100 that they expose and you develope for a proper chart. They have a special on the tube set right now.

Math gives me a headache. The book puts me to sleep with a headache.

Mike A said:

When I spoke with Fred, if I understood him correctly, I send in the unexposed film then they expose it to the step wedge. I then process it and send it back to them for my "numbers".

Math and my day job also put me in sleepy land.

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When I did my tests with Fp4+ 4X5, they just sent me the exposed film. I believe you supply the sheets for films they don't stock and for 5X7 and 8X10 films. You get a very detailed report with all the information you need.

I had some trouble getting into the book too, keep at it, it is worth the trouble.

--John

The best way to do BTZS testing is with a densitometer, step wedge and the film / developer combination you will work with (please, don't forget the paper). This having been said, there are plenty of other ways to work with BTZS numbers to get good results, it just takes longer, costs more and isn't as accurate. If proper notes are taken and development is known, the same films can be used for a different paper to get results that work.

I've been using a system which does the same thing, but without the densitometer. Although primative, it does a good job. I take a picture and work with the scene as if it were a film test. Take the usual notes on exposure and btzs sbr number, take a couple of shots. Take a guess at development to yield your zones 3 and 7, process and print. Where are the values in the final proof? If there was too much contrast, back it down and do another sheet, if too little contrast, add time. Once you have made this proper development, you have established one point to plot in sbr, time and development.(*** this is a guess at best, certainly not scientific)

While this may not be the correct manner of testing, it gives you numbers which work well enough for everyday shooting. Once the points are plotted, the numbers are "averaged" out with a french curve and you have enough information to do any scene you already know, and a decent way of dealing with contrast and development in ones you may not have encountered yet.
A simple comparison to known values of zones 3 and 7 on a stouffer printed paper strip gives the feedback you need to evaluate the process. As I have said, it is primative, but I have learned quite a bit from this testing method and it has certainly helped me to understand the relationship between exposure, development and the finished print.

I'm sure there must be errors in my process, but don't let the number business fool or confuse you. It may be dry, but the sbr numbers open a world of understanding which I was never able to get from the N, N+ and N- zone system stuff. The beauty of the btzs numbers (sbr) is that it is an exact 1:1 relationship between zones in a print and zones in the film's development. Once plotting is done, you can dispense with any testing and there exists an infinite number of development combinations for any lighting / development scheme you can find. The hard part for me was understanding that a stop of development in the film was much more than a stop of development on the paper. Due to my personal density index (quite high), when the light bulb finally clicked on, it was like a cool shower after too many months without rain. tim

P.S. Please don't confuse the sound of a light bulb clicking on with the sound of a toilet flushing, they are not the same.

Quote Noseoil:

"The hard part for me was understanding that a stop of development in the film was much more than a stop of development on the paper."

My response:

Not only is that true, Tim, but also a stop of film exposure does not remain linear insofar as density response on the film. For instance a stop of exposure on the toe or shoulder of the film characteristic curve may amount to far less then .30 of density change. In addition, I have found that on the straightline portion of the characteristic curve, that a stop of exposure may amount to .30 of density gain.

The paper does not care, in fact does not recognize or know for that matter, what a stop of film exposure amounts to; whether that stop of film exposure is one that amounted to a .07 change or a .30 density change on the film.

This is one of the major failures, in Zone System methodology, as I see it.

This is not intended to be viewed as Zone System bashing. It is to be viewed as the objective reporting of factual information based upon densitometric evaluation of film and paper.

"This is not intended to be viewed as Zone System bashing. It is to be viewed as the objective reporting of factual information based upon densitometric evaluation of film and paper."

Donald, thanks for this clarification of my post. It really does make sense, as the paper is the starting point. Perhaps my lack of experience made the zone system testing not as easy to understand as btzs. Once the relationship between paper and film development exists, many doors open. This was just the case for me. Whatever your methods, the print is the final judge of the process, not numbers, curves or zones. tim

Just out of curiosity Tim, I often wonder why you haven't picked up a densitometer yet? With your knowledge of the BTZS I would think that it would be such a help in your process.

Mike, the short answer is money. While not poverty stricken, my wife and I have placed my son's education above the needs of a second income. It would be nice to have her working, but the extra money would be at my son's expense, not fair for him. He already has a tough time in school (severely dyslexic) and we don't need to add to his burden. tim

P.S. So far, things have worked out well with btzs numbers. I found out recently that a fellow apug member has a densitometer, he lives about 2 miles away.