Processing times

[gbr1000]

I'm just starting out and I'll be using D-76 developer for TMax100 4 x 5. Just wondering how do you figure out how to calculate zone system development times for N-1, N-2, N+1 etc ? I know that in the zone system, you expose for the shadows and develop for the highlights. If there's any web site to guide me to would help.

Thanks

Gary

[bob carnie]

Gary

I am not a big fan of D76 for tmax film, I prefer Tmax developer.
Over the years and many tests tell me to stick with Tmax dev for Tmax films.

[biglewsmi]

That's a question with a fairly long answer, so I'll point you to a couple of sites that take you step by step.

http://www.viewcamera.com/pdf/2006/V...%20Started.pdf
http://www.halfhill.com/speed1.html
http://www.halfhill.com/speed2.html

Hope this helps.

[Louie Powell]

Gary -

You've asked a question for which the answer is a book!

You have two challenges. First, you must determine the optimum film speed for your choice of film, lens and meter. Basically, that is the speed at which you should expose your film in order to get a negative density of 0.1 over film base and fog when you are metering a Zone I subject.

After you determine your film speed, you need to do a processing test. There are sensitometric criteria that you can use, but it's often close enough to find a development time that produces a print from a Zone VIII subject that barely shows highlight texture.

That's easy to say, but not so easy to do. If you do a web search, you will no doubt find a number of articles that describe the techniques for performing each of these tests.

[Paul Bujak]

An excellent book is The Zone System Craftbook by John Charles Woods. It has chapters on "Zone System Visual Testing" as well as "Basic Testing Using the Densitometer". (I use a densitometer)

I find it very helpful as the information is well written in terms that are easy to understand.

Paul

[ki6mf]

A good place to get step by step instructions online is on Jerry Orabona's web site
http://www.jerryo.com/teaching.htm.

I recommend and use using D 76 and HP 5 diluted 1/3 developer 2/3 water. Normal development time for me is 14 minutes. I cut development time 2 minutes per stop of over exposure. N-1 is 12 minutes -2 10 etc. For compensating I use 1 to 5 with 15 minutes development and agitation every 2 minutes. I do not pre-soak. My ISO test is for ISO of 300 and you need to do a speed test for your light meter and development technique. Changing chemistry or gear in the middle of your testing results in guaranteed 100% failure!