Density tests to find optimal development time for pushed film

Anupam Basu · Sep 15, 2006

As I was reading (there was a url link here which no longer exists) I was trying to think of pushing film as the underexpose-overdevelop concept in zone system terms.

For normal shooting, I test all my film to establish an EI and then find development times for N, N-1, N+1 etc. I have a basic understanding of it in terms of controlling the gradient of the density curve to correspond with particular zones. But since development time does not really change the density of zone 1, how would you then test for pushing film?

For example, I need to shoot a concert handheld next week and would like to shoot Tri-X at 1600? In terms of density readings, how should I test for the ideal development time to give me maximum possible tonal range and also know that tonal range so I can place my zone values accordingly.

I have done this with the digital truth times before and had good results, but I would just like to have a better understanding of it and optimize the process. So, of the three factors - EI, development time, and density range (contrast) - if EI is given, how do you find the ideal cmbination of the other two?

I hope this is clear and thanks for any help,
-Anupam

Gerald Koch · Sep 15, 2006

TX does not push well above an EI of 800. You would probably get better results using Kodak Tmax P3200 at 1600 and following Kodak's instructions for development.

Or consider pushing Fuji Neopan 1600 or Ilford Delta 1600 a bit.

Anupam Basu · Sep 15, 2006

Okay, I will try with a different film. But my question about a procedure to test for ANY film for the best pushed times remains.

thanks,
-A

Donald Miller · Sep 15, 2006

The EI of the film does change with the development time. It is not a fixed quantity. This is something that the Zone System does not explain as well as other methods.

The direction that you are approaching this from is only valid in certain parameters. The materials do have limitiations within the sensitometric characteristics of the emulsion(s).

Perhaps you would be better advised to approach this first and foremost from determining the exposure scale (sensitometric qualities) of the paper that you are using. The density recommendations of Ansel Adams no longer are valid with certain materials.

Eric Jones · Sep 15, 2006

Hi Anupam,

The first "quickie" test I do with a new film and/or developer is a basic speed test. Here is a concise web page that explains it:

Dead Link Removed

Naturally, different films and developers are going to give you different film speeds, CI's, etc. Maybe start with the Digital Truth times and fine tune from there. This test has never let me down and it's the first thing I do when starting with a new film or developer/time combo. FWIW, I like TXT400 in Diafine and I get a true 1600 ASA speed out of it, using this test. But Diafine is a compensating developer and develops to a fixed CI of around 0.7 to 0.8, so you have to print on Grade 3 or 4 paper. May be good for you concert situation, since you may have super hot light sources in the shot as well as intense backlight. Have fun.

jstraw · Sep 15, 2006

Donald Miller said:
The EI of the film does change with the development time. It is not a fixed quantity. This is something that the Zone System does not explain as well as other methods.

I don't consider myself qualified to say whether or not the Zone System explains this as well as other methods, as I'm not familiar enough with other methods to know that.

I know that the Zone System makes this fact clear to me, as determining EI involves testing exposures for Zone III and determining N development involves testing development for Zone VIII. The fact that one does first the former, then the latter and the EI doesn't change while testing for N development seems to make this clear to me.

Roger Hicks · Sep 15, 2006

Dear Anupam,

The only meanigful test in this situation, I suspect, is to shoot something analogous and see what you find acceptable -- because in photography, 'acceptable' means a lot more than any form of sensitometry, including that (relatively small) subset of sensitometry known as the Zone System.

Alternatively, plot time/gamma curves for the film/dev in question, or if possible (increasingly difficult) obtain them from the manufacturer. Take spot readings of the darkest and lightest zones in which you want texture; calculate the requisite gamma from this, as described in the other thread; and develop accordingly.

Alas, most concerts will saddle you with a miserably low gamma, because the brightness range is very high. Time for another approach:

Base your exposures on spot skin-tone readings, which (again) you correlate experimentally with actual exposures. At least this will give you good skin tones...

Alternatively, just use Delta 3200 and use the Ilford 3200 dev times. It will beat the hell out of any ISO 400-650 film (Tri-X, HP5, Neopan 1600) regardless of how hard you 'push' them.

Cheers,

Roger

Paul Howell · Sep 15, 2006

Anupam Basu said:
As I was reading (there was a url link here which no longer exists) I was trying to think of pushing film as the underexpose-overdevelop concept in zone system terms.

Pushing film is not a concept that AA used in his verison of the zone system. He spoke and wrote about contraction and expansion as a method of controlling for apparent contrast. Pushing film is from the old days of press photography, to exceed the film's rated speed for shooting low light or long lens, the trade off is loss of shadow detail. I have never come across any film density numbers that relate to pushing film. When shooting with pushed film my motto was expose for the highlights and let the shadow fall where they may.

Roger Hicks · Sep 15, 2006

Paul Howell said:
When shooting with pushed film my motto was expose for the highlights and let the shadow fall where they may.

One could hardly be more succinct or exact.

Cheers,

R.

Donald Miller · Sep 15, 2006

jstraw said:
I don't consider myself qualified to say whether or not the Zone System explains this as well as other methods, as I'm not familiar enough with other methods to know that.

I know that the Zone System makes this fact clear to me, as determining EI involves testing exposures for Zone III and determining N development involves testing development for Zone VIII. The fact that one does first the former, then the latter and the EI doesn't change while testing for N development seems to make this clear to me.

I think that you would benefit from reading or rereading the Zone System as promoted by Adams. What you have written does not seem to address the initial question nor does it seem to follow the Zone System.

Eric Jones · Sep 15, 2006

Anupam,

I mistyped in my post above. I get 1600 ASA using TXP-320 not TXT-400, I only get 800 ASA out of TXT-400. Both using Diafine using the 120 roll film versions of these films.

Eric

Density tests to find optimal development time for pushed film

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