N+1=150% of development?

[Darkroom317]

I started a large format class this semester a couple of weeks ago. We have started learning the zone system. The instructor has told us that N+1 is 150%, N+2 is 300%, N-1 is 75% and N-2 is 50% of overall development time. I am curious as to what others think about this.

I have been using the zone system for over a year now with 120 film and multiple backs. Everything I have read says that adding 15%-20% is equivalent to N+1. This is what I have been using for the past year. Who is correct? Having I been doing it wrong this whole time. Will doing what he says actually increase/ decease the highlights by a full zone.

 

[Chuck_P]

my N times for TMX and D-76 1:1 are:

N = 8 min
+1 = 10 min or 25%
+2 = 11:30 or 43.7 %
-1 = 7 min or -12.5%
-2 = 6:30 or -18.75%

Your Prof is mistaken, IMO, as far as determining basic "N" developing times. But some situations can involve extreme measures that may involve changing the agitation schemes, developer dilutions, etc...but for basic "N" compensation, no, as far as my own work goes anyway.

I have developed negatives exposed to very low SBR (1:4) for 3x my "normal" of 8 min for a 24 min developing time, that was a 300% increase in development even using standard inversion agitation at 1 min intervals. You can see the result of that negative on my Flickr---see "Yellow-Poplar Leaves".

 

[tkamiya]

Ask him what film/developer combination he is talking about.... What it takes to slide the film one stop on a scale depends on an exact combination. You can't generically say, for N+1, 50% or 20% more.

 

[polyglot]

He may well be right for a specific film/dev combination as they all differ. +50% time is a big expansion for most films though.

Best way is to expose a couple test strips from a wedge and run a densitometer over it. That will give you a definitive answer on the contrast you're achieving.

If you're struggling with ZS concepts, get "Beyond the Zone System" (BTZS) by Phil Davis. There are plenty of secondhand copies floating around cheap and you can read it cover-to-cover in a couple nights assuming you already have a passable grasp of mathematics.

 

[artonpaper]

A good starting place to determine N+1 development is to multiply your standard time by 1.4. For N+2 you can then multiply that time by 1.4 again. Differnet films and developers will of course generate different results, but this g=has worked as a very good starting place for me. usually getting me very close to my target densities. I might add that N-1 can obtained by dividing your standard N time by 1.4. This is what I learned back in the 70s while studying the Zone System with John Dowdell, coauthor of The Zone Systemizer, along with Richard Zakia.

 

[RalphLambrecht]

none of these factors work reliably.trust me, only a proper film test will do

 

[Darkroom317]

I figured as much from everything I've experienced and read: Like I said, I've been using ZS for over a year.

Ralph, I use your book in place of the recommended text book

 

[Bill Burk]

Darkroom317,

As has been pointed out, your instructor is mistaken. The numbers he quoted are not the kind of time series that you would find by testing (like CPorter's times, which I'm familiar with from looking at his curves.)

However, look at it from the point of view of "how bad" the advice is... It's not that bad. For the shot you need N+2, if you develop 300%, you have a fighting chance of pulling out a workable negative. The converse is true, N-2, developed 50% the time, would hold the highlights in check.

And, it's very likely it will be on the test. So go ahead and commit it to memory.

 

[pgomena]

It depends entirely on the film, developer, exposure, agitation scheme, and developer temperature. That's five variables that need to be controlled.

A "rule of thumb" will get you in the "ballpark." Experience will get you into the infield. Testing will get you into the batter's box.

 

[henry finley]

It would seem to me that the Zone System of development would require a developer that works in a totally linear fashion, which I believe, is why Adams settled on D-23. It is not an Elon-Hydroquinone combo that works in an un-linear fashion. (I use the word linear for lack better word in my personal vocabulary). But I believe my object is understandable. D-76 was the most popular Kodak product, but not necessarily the best at all. Lacking a pound jar of Elon/Metol, and a big canister of sulfite, I'd say the closets thing pre-packaged would be straight Microdol or the Ilford equivalent. I could be wrong, but best of my knowledge, Microdol was an Elon-only product. D-76 did one thing very well--gave a rigorous development with plenty of grain.

 

[Terry Christian]

Extending (or shortening) development times by as much as 150%, 200%, etc., is essentially pushing (or pulling) the film. With Zone System N+ or N- development, the goal is not to push or pull, but to gently tweak the contrast level to fit it into the range the film or paper can hold.

 

[henry finley]

I did not know Adams had switched to HC110. I suppose the 5-book series I read back in the 70's and 80's could have been at the branch library for a coon's age. The HC110 news is new to me. I never used it. I don't even know what's in it.

 

[Usagi]

I have found that N+1 time is usually 25-45% longer than N time. Most films gives N+1 around +30% time.

N+2 is hard to reach with my methods. Perhaps it could be something like 150% =)


I use slosher for sheet film with D-76 1+1 at 20°C. For roll film I use normal tank and inversions.
If I would really need N+2, I would do test set with some stronger developer for N+ times.

 

[Darkroom317]

The other thing that he asserts is that we should always be able to print on grade 2 if we use the Zone System. I have heard this other places but I have heard if refuted. Even Adams said that some people consider grade as their "normal" grade. Since I switched to the Zone system, I have noticed that I generally used grades from 2-3.5. I have color enlarger in my darkroom so I can go down 1/8 grades. I am happy with the prints I have been producing with this. Also, if your negative is perfect, why would you need to dodge and burn which I use extensively. I like my prints so none of this really matters but I am rather curious on thoughts about all of this. I must keep in mind that my instructor says we should never crop and that the square is more difficult to compose.

 

[RalphLambrecht]

In particular, the notion the Zone System leads to perfect negatives that require no burning, dodging etc. is preposterous. The "perfect" negative is one that contains all the information you need to make the print you envisioned or "visualized" when making the photograph.

this is exactly rightandshould be taught as the first commandment of the zone system. this would avoid much confusion from the start

 

[Chuck_P]

this is exactly rightandshould be taught as the first commandment of the zone system. this would avoid much confusion from the start

+1

 

[Stephen Benskin]

A good place to get a feel for the rate of development of any film/developer combination is from the manufacturer's time/gamma curves.

 

[RalphLambrecht]

I GOT FAR MORE RELIABLE RESULTS FROMcustmized film tests.probablybecause exposure and development is conductedwith my equipmentand workflow.

 

[JBrunner]

Extending (or shortening) development times by as much as 150%, 200%, etc., is essentially pushing (or pulling) the film. With Zone System N+ or N- development, the goal is not to push or pull, but to gently tweak the contrast level to fit it into the range the film or paper can hold.

Yup, in addition to testing to find the actual development needed for your film/developer combo, the film needs to be exposed in the first place with the intention of expansion. Just over cooking film for some arbitrarily stated time doesn't necessarily get you N+ anything but a bullet proof negative.