N+1=150% of development?

Discussion in 'B&W: Film, Paper, Chemistry' started by Darkroom317, Jan 27, 2013.

1. Darkroom317Member

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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.

2. CPorterMember

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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".

3. tkamiyaMember

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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.

4. polyglotMember

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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.

5. artonpaperSubscriber

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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.

6. RalphLambrechtSubscriber

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

7. Darkroom317Member

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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

8. Bill BurkSubscriber

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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.

9. pgomenaMember

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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.

10. henry finleyMember

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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.

11. Terry ChristianMember

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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.

12. michael_rSubscriber

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Henry, a few things:

1) Adams ultimately settled on HC-110

2) Generalizing about curve shapes based on the developing agents is an incorrect approach. Little can be said about the characteristics of a developer without looking at the concentration of developing agent(s), the concentration of preservative (Sulfite) and the concentration/type of alkali (pH, buffering). As an example, G. Haist (Kodak) created a modified version of D-76 with identical working characteristics (but less capacity) by slightly increasing the amount of Metol (Elon) and omitting the Hydroquinone entirely. D-76 is a fine grain developer very similar to D-23 in practice.

3) Microdol is said to be D-23 with a little less Metol (5g/l rather than 7.5g/l) and somewhere around 30g/l Sodium Chloride. Microdol-X contained at least one extra ingredient - an anti-silvering agent.

13. henry finleyMember

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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.

14. michael_rSubscriber

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It's a concentrated syrup. The exact formula is proprietary but based on the published patents and MSDS the developing agents are Phenidone (or one of the Phenidone derivatives) and Hydroquinone. It is a traditional favourite of Zone System users, mostly because Adams was using it in the 70s/80s, and because it is easily diluted to different working strengths. It also last a long time. The working characteristics are very similar to D-76.

15. UsagiMember

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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.

16. Darkroom317Member

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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.

17. michael_rSubscriber

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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. Straight prints are very uncommon, even with great negatives. Adams put a lot of effort into his prints, and used whatever grade of paper he needed. Many of his more famous images were printed on grades other than 2.

The Zone System is not an easy way out. It is simply a tool to help you get more predictable results.

Never crop? Why not? The "never crop" thing is just an attitude or personal mantra. It means nothing.

The instructor seems like a stubborn, opinionated person with not much actual technique to teach. Unfortunately in an academic setting you've got to do what the guy says for now so you get a good grade.

18. RalphLambrechtSubscriber

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

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+1

20. Stephen BenskinMember

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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.

21. RalphLambrechtSubscriber

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

22. JBrunnerModeratorStaff MemberModerator

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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.