TMAX Developer... when should I throw it?greenspun.com : LUSENET : B&W Photo - Film & Processing : One Thread
I'm a complete newbie in B&W processing, please forgive my ignorance. I developed 2 rolls with the same developer but not shure how long will keep the chemical properties and give decent results? Same question will be for fixer.
Thanks for your he
-- Felipe Huicochea (firstname.lastname@example.org), June 17, 1999
For the fixer, the standard rule is to find how long fresh fixer takes to 'clear' the film. This might be, say, 2 minutes. You can carry on using it until this clearing time doubles (in this case, to 4 minutes).
Film developer is more difficult. I used to use T-Max once only. Then I read the instructions, and noticed that Kodak suggested you could reuse it twice (for a total of three times). I have tried this, and it seems to work. I increase development time by 20% for the first reuse, and another 20% for the second.
I haven't done proper testing on re-use, such as using a densitometer on the blacks. For critical work, I don't use second-hand developer.
-- Alan Gibson (Alan.Gibson@technologist.com), June 18, 1999.
As a newbie you probably want to simplify the situation. Until you have a real feel for your gray scales, use your neg developer only once. Get in the habit of simply pouring down drain each time. Chemicals are cheap. Consistent development is everything.
As for fix, I strongly recommend a nifty product called "Hypo Check". Comes in a small eye-dropper plastic bottle, a single drop tells you when fix is shot.
-- Standish Lawder (email@example.com), July 21, 1999.
If you save the narrow leaders that you cut off of the film before developing, you can use them to check the fix. Fresh fixer might clear felm in 45 seconds. If it takes twice as long, the fix should be discarded. The product named Hypo Check costs about a penny per check, but is more sensitive than using scrap film. As for developer, with less expensive developers, using once and disgarding is practical and safe. I mix T-Max developer a liter at a time, and run maybe 20 or thirty rolls of film through it over several weeks, increasing developing time gradually until I might develop an extra minute before disgarding the developer. It isn't scientific, but, by closely checking the film for proper development, it works for me.
-- jim jones (firstname.lastname@example.org), July 23, 1999.