IanBarber
Member
Thank you everyone for responding and I have learnt something else new now
No its because the lower Zone densities are determined by exposure (ASA) not development. You can develop the hell out of Zones I - IV and the densities won't increase much compared to Zones VI thru VIII.It is confusing because no one ever really knows what someone else is saying unless they are very detailed in saying what they actually mean. For example, according to Adams, N+1 leaves zone IV on zone IV, so using your interpretation then zone IV would become zone V. And since everyones interpreation is different, discussion about the zone system becomes a very big circle of confusion.
N-1 indicates lowering Zone IX to VIII. With most film/developer combinations this requires about a 25% reduction in development time.When people refer to N- and N+ I know they are either extending or shortening the development time but when they say N-1 or N+1 (what does the 1 mean) in terms of development. Does it mean 10% ?
I'd also like to add that, before doing the tests, I check the shutter speeds for the lens used. I also have the habit of changing apertures in the "closing down" direction to eliminate the mechanical free-play from causing any error (no idea how much that error can be); this was suggested by AA - the geek of geeks - at a '66 workshop, so I just do it.
N-1 indicates lowering Zone IX to VIII. With most film/developer combinations this requires about a 25% reduction in development time.
N+1 indicates raising Zone VII to Zone VIII which requires an increase of 40% in normal development time.
These percentages are not always exact, but generally they are very close.
However his system did apparently work for him, as he seems to have had a measure of success with it. Dead Link RemovedDead Link RemovedDead Link Removed
The zone system tries to capture the whole curve and its dependence on development by focusing on a few points only. In particular it defines film speed as a fixed density above base and fog, irrespective of gamma or contrast index. However, the ISO film speed specifies a gamma of 0.62 and a density of 0.1 above base and fog. I think that this explains why most people using the zone system find an EI around 1/2 of the ISO speed, since the zone system aims for a lower contrast index than ISO does. Is this correct?
Good grief. Now I'm wondering whether E really equals mc^2. Surely by now there should be a standard that confirms it or a contrasting theory that attempts to disprove it.![]()
Adams in actuality wasn't very good at theory. The aims for NDR and Zone I are based on a misconception. Ever wonder why the LER for Grade 2 paper for a diffusion enlarger is 1.05 and Adams has a 1.15 - 1.25 for the NDR? Or how ZS film speed testing almost universally results in EIs 1/2 to one stop slower than the ISO speed?
Good grief. Now I'm wondering whether E really equals mc^2. Surely by now there should be a standard that confirms it or a contrasting theory that attempts to disprove it.![]()
Stephen, certainly not to take issue with what you've said, but I'm curious to know if anyone has integrated all that info that's "out there" into a published system that could conveniently be used by photographers in the field (similar to the Zone System). Perhaps it could be called Zone II (that'd really confuse everybody though) or BTZS II.
The film and paper that Adams used were different than those today. IN most cases, significantly so. Tri-X of today has little if any resemblance to the Tri-X of the 60's. Super XX hasn't been produced in years and many of his images were made with that beautiful straight line film. I occasionally pull a few sheets out of the freezer to use just for old times sake.Adams in actuality wasn't very good at theory. The aims for NDR and Zone I are based on a misconception. Ever wonder why the LER for Grade 2 paper for a diffusion enlarger is 1.05 and Adams has a 1.15 - 1.25 for the NDR? Or how ZS film speed testing almost universally results in EIs 1/2 to one stop slower than the ISO speed?
The film and paper that Adams used were different than those today. IN most cases, significantly so. Tri-X of today has little if any resemblance to the Tri-X of the 60's. Super XX hasn't been produced in years and many of his images were made with that beautiful straight line film. I occasionally pull a few sheets out of the freezer to use just for old times sake.
The basic reason for the difference in ISO speed, and a practical exposure index has to do with the method used to determine ISO. The developer is different, the exposure is very exact using very accurately controlled light sources, and the film ios fresher than any you will ever get from a retail source.
It's all out there if anyone is interested in moving beyond The Negative. It appears to be down right now, but here's a link to a number of key papers.
http://64.165.113.140/content/benskin/
Adams in actuality wasn't very good at theory. The aims for NDR and Zone I are based on a misconception. Ever wonder why the LER for Grade 2 paper for a diffusion enlarger is 1.05 and Adams has a 1.15 - 1.25 for the NDR? Or how ZS film speed testing almost universally results in EIs 1/2 to one stop slower than the ISO speed?
I disagree. He simplified a complex subject so that it's easier to apply.
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