CONTINOUS AGITATION

[sajjad]

Am i correct to say , that if i wanted to reduce my developing time

i can choose continous agitation? if yes by how much reduction in

developing time do i require to reduce?

My regards to all

[macgregor_anderson]

There is now way to answer that question simply. Depends what method you are using, how you agitate now, what chems and film, etc. You would need to test for yourself, making sure that you were as consistent as possible.

 

If you are using roll film for instance in a tank, maybe shoot a roll with 11 zones on it and develop it in your regular way. (don't leave the rest of the roll blank, fill it with some other shots, but leave one or two frames blank) Contact print them at the standard time it takes to achieve maximum paper black on the clear portion of film.

 

Then shoot another few rolls of the same and develop with constant agitation for say 10%, 20%, 30% less time. Contact those for the same time and see if you get the same result in any of them.

 

You will want to keep everything else the same, and be as careful as you can be. Develop freshness, temperature, etc. Best to use a tripod and shoot a neutral colored wall or something, middle of the day, in the shadows.

 

You might consider before doing this first testing to see if you are developing for the right amount of time already. And before that if you are shooting at the right speed for your methods.

 

This has been explained before in zone testing on the forum. Basically you first shoot some frames at 2, 3, 4 and 5 stops under your meter reading (trying to find the right zone I for your film) and develop those for your usual time. Do a standard contact print and see which one is just above black, first discernable grey. If it's not 4 stops then you need to adjust your film speed accordingly.

 

Then shoot some zone V stuff. Develop for various times around what you usually use. See which time gets you a contacted zone V (use a grey card for a reference). Now you've got your film speed and development time.

 

I suppose you can do that step with constant agitation. But you may find problems with extreme contrast, uneven development, streaking, etc.

 

That's the long answer. The short answer is to just experiment a bit and see what looks good to you and gives the most printable negs.

 

mac

[__jon__]

I use a rotary and generally reduce manufactureres' suggested time 15% or so depending on the film and scene. Read more here:

 

http://unblinkingeye.com/Articles/Rotary/rotary.html

[grain]

The development times I use for EFKE 25 in Neofin Blue are:

3:45 with continuous agitation//

8:30 with four inversions each thirty seconds. Both with one min. pre-soak. Both at 68f.

 

It makes a difference in the contrast levels, the 30 second agitation method yields slightly higher contrast. (one would expect the opposite)

[ronald_moravec1]

Some developers work well and other do not. D 76 types seem fine and others like rodinal suposedly like the rest periods. Reduce your normal times by 20% with a N subject and test print. Adjust from there and then apply the same correction to all previously detirmined plus and minus times. This will be close.

[esa_tuominen]

I am also changing to rotary processing with a Jobo Duolab. It runs at 24 C degrees by default, and the recommended times for Xtol 1:1 at this temperature for FP4+@125 produced awfully contrasty thick negatives. I'm still in the process of testing, but I seem to be approaching something like 4 min developing time.

Does anyone else have similar experiences?

[david_beal___richmond_hts.]

I've found that continuous agitation works well for sheet film (old Tri-X) in BTZS tubes (I typically use Rodinal 1:100 at 20 *C for 20 minutes), but it isn't so good for Ilford DD-X (which I use for all Delta films). In that instance, I begin development with 1 min. of continuous agitation, and follow with 5 sec. agitation every 30 sec. That seems to be best for that developer. YMMV.

 

Best wishes.

[lex_jenkins]

The straightforward answer is: yes.

 

The realistic answer is: it depends.

 

Meaning, it depends on whether it's a good idea. Speaking only for myself, I find continuous agitation or frequent agitation (35mm or 120 on reels in tanks) to be difficult to control. For example, recently I got extremely dense negatives with Efke R100 in Neofin Blue and continuous agitation (data extrapolated from various sources). But the same film and developer with "normal" agitation intervals produces excellent negatives.

 

I suppose if I worked at it more I could come up with some reliable data and reproducible results. But in most cases it doesn't seem worth the effort.

 

An exception would be when it's impossible to achieve the desired contrast/gamma (sorry, I tend to use these terms imprecisely) with a given film, developer and normal intervals between agitations. That can occur with Neofin Blue, among others.

[__jon__]

>David Beal , may 28, 2004; 10:17 a.m.

 

>I've found that continuous agitation works well for sheet film (old Tri-X) in BTZS tubes (I typically use Rodinal 1:100 at 20 *C for 20 minutes), but it isn't so good for Ilford DD-X

 

I've been using DD-X in my rotary with several films, all with great results.

[Bilal Zaheer]

Whoa... continous agitation... and I thought it meant you continously go and agitate till the guys develop it faster for you haha! hmm really have so much to learn.

[lex_jenkins]

Definitions and techniques for continuous agitation vary. With rotary systems agitation is truly continuous. But with hand agitated tanks the usual practice is to invert the tank about once every 3-5 seconds. Either way it'll take some experimentation to get good results since most published data is for agitating every 30-60 seconds.