tonal charcter of films

Donald Miller said:

Actually the way that I determine the curve of a film is to expose the film to a calibrated step tablet or wedge. When one does it that way the exposure will enable you to find both the speed point or EI of the film and also then determine the characteristic curve of the film by reading the corresponding negative ransmission densities.

This is at departure from what the Zone System practice indicates but it is far more accurate in my experience. Hope that this answers your question.

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Thanks Donald, that makes sense. I suppose photo supply stores like Calumet or B&H sell the calibrated step tablets?

mhv said:

Thanks Donald, that makes sense. I suppose photo supply stores like Calumet or B&H sell the calibrated step tablets?

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These can be ordered directly from Stouffer. At least that is how I purchased mine. www.stouffer.net

Good luck.

An example of scale, film vs. paper. Let's say you have a film scale of 8 stops, but paper is only 5 stops. What happens when a full stop of development is added to the film itself, without regard to the paper's scale? If we have done things correctly, the film's one stop would be 8/5 of a stop on the paper, or about 1.6 times brighter on the paper, than we would think if we just look at the film numbers (0.3 units of density). So a stop of development in the film isn't really a stop on the paper, is it?

This is why I like btzs numbers over the zone system. It just gives us different numbers to work with. It uses the paper as a point of reference, and then ties development to the film. Really much simpler to figure things out this way, but it takes a bit of tinkering if there isn't a densitometer handy. tim

Working with a step wedge is really essential to gain a practical knowledge of how film and paper works.

It also gives you the groundwork to experiment, or PLAY, with variations of combinations, to see how they affect the paper or film.

It is like sitting down to a piano ( preferably, a tuned piano ) and learning your scales. As you practise them to be able to play them, you also teach yourself how to listen, and in time you have them in your subconscious.

In time you may find the literal representation of a step wedge feels a lot like major scale, and the images you make of the step wedge on different contrast papers, with different development, etc., may remind you of different scales and modes.

I think this is the intersection of technique and creativity. You KNOW what the values of a step wedge are, and when you can reproduce them literally on a sheet of paper, you have fixed the printing process, and can be confident of THAT part of the process. As you work with films and developers, you can SEE what the character of the combinations are. Have fun.

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lenny said:

There ar films, and then there are films. Beffore I say anything, let me say quickly that it depends tremendously on what kind of print you want to make and how... Darkroom materials can only handle a certain density range in a negative, unlike platinum or scanning and printing via inkjet.

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And yet I understood that one of the problems of printing digitally was/is blocking of highlights/ shadows - or is this not quite the same thing necessarily as tonal range (Does it mean you can in fact get a better tonal range - in general - from inkjet printing??)

Dear Loveminuszero,

I think it might be time for you to quit relying on internet posts and to actually do the heavy lifting. In your original post you said that you understand the zone system--expose for the shadows and develop for the highlights. This is the basis of the system, and for BTZS. But, you don't understand film curves, paper curves, how zones are represented graphically, etc.

There are some wonderful things called books. You can find them in book stores and libraries. I suggest you go get some and actually start a program of reading to understand this stuff as a whole, instead of trying to peice it together from the internet.

I recommend Johnson, The Practical Zone System, as a place to start. Also, Davis, Beyond the Zone System, for a more detailed explation of densitometry.

The internet is a wonderful thing, but it is no substitute for actually doing the research yourself.

Allen