Zone System: How is "normal" EI/developing time determined for Tri-X 320 with HC-110 dil B ?

in a sentence, the Zone System is over- (or under-) exposing, relative

to "normal" EI, and under- (or over-) developing, relative to "normal"

developiong time.

 

sounds easy in theory. if one knows the "normal" ISO, one can easily

determine by trial and error what is "normal" developing to arrive at

all 11 zones in proper relative density. the converse is also true.

but, since manufacturers' published ISOs are just "starting points"

and recommended developing times, likewise, are just "starting

points", there are an infinite number of "starting points" one can

choose for both EI and developing.

 

at the moment , i'm trying to determine "normal" EI/developing time

determined for Tri-X 320 with HC-110 dil B. how do i avoid having to

test an unlimited number of "starting points"?

errrrr.....you can't.

 

Not technically, anyhow. Exposure, ISO rating, is determined by the amount of exposure it takes to change the density of the negative above is's base density. Developement is determined by the amount of development it takes to place the zones of density, up to X, in a "normal" contrast scene, or scale, so that it prints on #2 paper properly.

 

Expose for the shadows, and develop for the highlites.

 

I think what you are missing in the process is that development (within reason....2 seconds aint gonna cut it ;o) has very little bearing on what that first zone of density is. In other words, for that first density above the base density you just use the manufacturers recommended development time, and step thru all the possible deviations of exposure from the base ISO, and the one that reads a certain value (which i now forget, but it's all over the zone system books) above base is the proper ISO............regardless of development time. Then you take that ISO and run it thru all the different development times..........etc.

 

I believe I said that correctly. Anybody have the books in front of them can probably shoot me down on a couple points, but i think i remembered the basics correctly.

there are several ways to test. but no easy way as the above thread indicates. Tests are usually in two parts. the first part is to determine the EI. which is .01 above film base plus fog. This would be the EI for your equipment.

 

You would develop the first part using the recommend times for that film rated at the recommended ISO. After determing your EI you would then run a second test using that value to determine development times. Depending on the light source in your enlarger you would aim for a denisty of 1.20- 1.25 for Zone VIII.

 

I would suggest you check out several books for the specifics as it would take too much space here to give a blow by blow. THere is ANsel Adams. "The Negative", Fred Picker's "Zone VI workshop", Minor WHite's "Beyond the ZOne System, Les Mclean has a new book out "Creative Photography" using a different method. I am sure there will be others out there to add to this list. Find the method that works for you and stick with it, I would not recommend bouncing around from one author to another as that can become mind bending.

 

Testing is not difficult, jut boring. It is more complicated to write about than to do. But the pay off is better negatives , easy printing. HOWEVER, using the Zone System does not mean you will not have to burn and dodge. Basically you are controling the contrast range of the negative which hopefully limites the amount of burning/dodging.

 

It can take just one roll to determine the EI rating, but it might take severals rolls to detemine development times.

 

Another option without a lot of testing is to rate the film at half the recommended ISO, develop at recommended times and check your results. Is the shadow detail there, are the highlights blocked up? Adjust if need be. THis method really does involve "infinite starting points" (IMHO)

 

WIth the combination you are using we rate the film at 200 and develop for 6 to 6 1/2 minutes (depending on student) in HC110 dil b.

Under our conditions in our environment this works. Whether these numbers work for you is an unkown. you will have to check for yourself.

That matches the way I understand it, Thomas, with the exception that some developers and processing methods actually can/will alter the "true" film speed, the sensitivity in the toe, Zone I. For instance, some Phenidone based "acutance" developers will give anywhere from 1/3 stop to a full stop of increased true speed with "normal" development, and a strongly compensating "contraction" in highly diluted developer (N-1, N-2, etc.) can sometimes do the same by allowing shadows to continue to develop while highlights have locally exhausted the developer. "Expansion" can do the same, to a small extent, as extended development to increase contrast brings up the shadows a little (very little, usually no more than 1/3 stop for anything a Zonie would do to his film).

 

So, to establish N, you do what you said -- but then you have to start over, more or less, to establish correct speed for N+ and N- processes, especially if, as is generally necessary with modern films, you have to change more than just time to expand or contract the scale; depending on your particular materials and methods, I've heard of people changing EI by as much as two stops (frex, shooting TMX at EI 25) when shooting high- or low-contrast scenes, in anticipation of expanded or contracted processing.

As Donald points out, different developers can effect the speed; however, just pick one film and one developer to test or your brain will cramp up; especially for a beginner.

 

ALso, when pushing or expanding film you will underexpose and overdevelop; when pulling or contracting you need to overexpose and reduce development time. Both need to happen.

 

Once you determine Normal speed and development the + - times should go quickly as you don't need to establish a new base .

Just remember every time you change film or developer combos you need to start over, or if you are using a camera that has the shutter in the lens, you need to test each lens as they can vary.

It is not uncommon for LF users to carry a little guide to remind them how to rate and develop for each piece of equipment. This is the reason the ZS is used primarly with sheet film.

 

THis is not to say that you can't use the concept with 35mm, and understanding how to control contrast can be very helpful.

thanks to all. i have been (slowly) reading Ansel Adams's The Negative". thanks to Ann's reference to it, i found that Appendix 1 contains instructions for testing film.

 

i plan on using the Zone System primarily with a Speed Graphic 4x5. however, i am beginning testing with a Mamiya RZ67II. i realize that i will have to runs tests for the Speed Graphic; but, i'd rather learn how to do this with 120 film, instead of starting out with 4x5.

just a tip. keep carefull notes. it will help to make a chart. THen if there is a problem you can double check exactly what you did. It is very common to get lost the first time you run a test. I will double check my files and see if i have something i can send you off line.

Dear Gaetano,

 

Shoot a typical subject -- whatever you normally shoot -- at a range of EIs: for example, 200-250-320-400-500 for an ISO 400 film. Develop the film acording to the manufacturer's recommendations.

 

The EI for you is the fastest that gives a tonality you like. If that prints on grade 2 or 3, you have your 'N' time. If it doesn't, change your dev time until it does. More dev time gives more contrast (so you will need softer paper) and less dev time gives less contrast (so you will need harder paper).

 

Ask yourself if you are really ready to use the Zone System. From the questions you are asking, it may be that you are not -- and by the tume you understand enough about basic sensitometry to get the full benefit of the Zone System, you may decide you don't need the Zone System anyway. It's only a subset of sensitometry after all.

 

Many photographers try to run before they can walk, jumping into the Zone System too early. I know: I was one. Then I learned a lot about real sensitometry and decided that the Zone System was a waste of time, a search for a precision that doesn't exist and isn't needed.

 

At least as many great photographers don't use the Zone System as do use it. What does this tell you?

 

Cheers,

 

Roger

<i>WIth the combination you are using we rate the film at 200 and develop for 6 to 6 1/2 minutes (depending on student) in HC110 dil b.</i>

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Ann, it sounds like are you a teacher at a photography school.

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have you also found values for N-1, N+1, N+2, etc.?

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btw, i don't have a densitometer, or ready access to a darkroom for printing. i was planning on visually inspecting negatives to see if Zone V matched the gray card, and that there is a normal distribution of the other 10 zones.