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# Thread: Plus and Minus Development Percentages

1. ## Plus and Minus Development Percentages

Stimulated by a couple of recent threads and some testing I've been doing, I'm just wondering what people are finding *in general* for N+1 N+2 N-1 and N-2 development, given as percentages of Normal. Do you find it depends highly on the developer, or do the percentages stay pretty much the same?

Tim

2. I use 15% for traditional films and 10% for T-grain films.

3. Originally Posted by david b
I use 15% for traditional films and 10% for T-grain films.
That would be for +1 and -1? This is less than I would have expected.

4. yes +1 is 15% more development

-1 is 15% less development

5. Most developer manufacturers will provide augmented development times for their film, such as Kodak's literature available on their website, but your getting some pretty good numbers here. It's mostly trial and personal preference after time.

6. Tim,

My tests for 4x5 T-Max 100 shakes out as:

N+1 = +25%
N+2 = +44%

N-1 = -12.5%
N-2 = -31%

I can't provide any insight to the second part of your question because I've only tested thoroughly with D-76 (1:1). I'll be doing some testing with Microdol-X sometime in the not too distant future. I've been reading that it has some pretty decent compensating affect with TMX.

Chuck

7. Originally Posted by CPorter
Tim,

My tests for 4x5 T-Max 100 shakes out as:

N+1 = +25%
N+2 = +44%

N-1 = -12.5%
N-2 = -31%

I can't provide any insight to the second part of your question because I've only tested thoroughly with D-76 (1:1). I'll be doing some testing with Microdol-X sometime in the not too distant future. I've been reading that it has some pretty decent compensating affect with TMX.

Chuck
Interesting- these are some pretty different numbers- close to what's recommended for the minusses but quite a bit more than the general recommendations for your plusses. And with a T-grain film too......

Tim

8. I think that the percentage figures are rough numbers. Unless you do your own tests, everything is a rough approximation. I suggest that you use development times that are easy to remember and intuitive, e.g. times like 4 minutes, 5.8 minutes, 8 minutes, 11 minutes.

I did TMAX 100 4x5 testing with TMAX 100 developer using the BTZS process with the results measured by the View Camera Store. My results in BTZS tubes at 75 degrees differed quite a bit from published numbers but seem consistent.

For minus through normal development, I use TMAX RS developer at 1:9 dilution. For plus development I use 1:4 dilution. The processing times range from 4 minutes in dilute developer for minus development to as long as 16 minutes in stronger developer for plus development. I can range from about N-2 to N+2.

Don't forget that film speed changes with development, in my case by a considerable degree. Film speed is slower with contracted development and higher with expanded development.

9. ...
For minus through normal development, I use TMAX RS developer at 1:9 dilution. For plus development I use 1:4 dilution. The processing times range from 4 minutes in dilute developer for minus development to as long as 16 minutes in stronger developer for plus development. I can range from about N-2 to N+2...
Anyone else use dilution to push 'n pull?

I used to use HC-110 at various dilutions and a set development time and temperature (6 minutes 20C). [Since I've gone more primitive (SF lenses and salt or vdb printing) most stuff gets dilution A or stronger to pop the contrast and increase the negative density range.]

Anyone have contrast index or G-bar numbers for N, N+, etc.,? I should have some to compare in a couple days as I work through some tests.

Joe

10. I would have to go with Porters numbers - 10 and 15 percent has not worked for me - that is just the compensation for variations in temperature - not a significant density change - at least for developers that normally take 10 minutes to get to N

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