How important is agitation?

<p>I started wondering how much difference agitation makes?<br>

MY normal way of developing is that I invert the tank for 30 sec after filling then invert 6 times (10 sec) every minute for the rest of the development.<br>

I'm willing to do the tests but if there is someone who can answer this then I would not have to spend the roll's and developer. <br>

I figure that to get some kind of decent result I should do the following:</p>

<ol>

<li>set up somekind of still life scene.</li>

<li>select a comon film (for arguments sake: Ilford HP5+ 120)</li>

<li>meter it and use that setting. (Let's use say 1/15 and f5.6)</li>

<li>get the camera on a tripod and blast away 4 rolls</li>

</ol>

<p>Now that I have the 4 exposed roll This is how I would develop them:</p>

<ul>

<li>the first is just 6 minutes in rodinal 1+25 and sit there, apart from a few taps to dislodge air in the begining (All I have is Rodinal, and 1+25 is the dilution I always use)</li>

<li>the second one will be done the usual way ( see above)</li>

<li>a third one wil have erratic and slightly random agitation </li>

<li>fort the last one I probably know one of the side effects I will get: a sore wrist ;-) as I will be inverting it for the full 6 minutes.</li>

</ul>

<p>The reason I would take 120 is that it only takes 12 shots per roll and the larger negatives would make it easier to see the differences.<br>

It would probably take a lot less time with sheet film but I don't have large format camera.<br>

So if you might be able to shed some light on this than please let me know otherwise I'll keep you posted of the experiment.<br>

Regards,<br>

Erwin.</p>

 

<p>Without agitation, you'll get underdevelopment, since the developer that is in contact with the film will become exhausted and there is no movement to slosh fresh developer into contact with the film.</p>

<p>Proper agitation isn't just important, it's critical. All the data available on the subject comes from years of experience. The tests you suggest amount to to trying to re-invent the wheel.</p>

<p>Our father Ansel Adams would agitate constantly for the first minute, and then once every minute. You don't need to invert it six times. Twice, slowly, with a big tap is enough.</p>

<p>I use Ilford's recommendations:<br>

<a href="http://www.ilfordphoto.com/Webfiles/2006210204272065.pdf">Ilford pdf file</a></p>

<p>Do you really want to know? Track down a copy of Grant Haist's tome "Modern Photographic Processing." It's two volumes and most university libraries will have a copy -- check their card catalogs on the 'net.<br>

Haist did vast amounts of research into agitation while he worked at Kodak. Most of what he found out made it into his master work. Suffice it to say, agitation is one of the main variables in processing film.</p>

<p>It is very important, however, the published inversion and rotation systems are horrible, just barely better than than no agitation at all, but not much better.</p>

<p>Regarding the plastic tanks with the "spinner" type agitation, this actually works! For the first 15 seconds, spin two to the right and two to the left repeadedly. After than, for each cycle, 2 to the right and 2 to the left and leave it alone 'til the next cycle. If you fog film to a density 1.00, this will give you 1.00 +/- .04 to .05, (1/6th to 1/7th f stop) that is quite good relative to the information given to us by Kodak back some years which says that +/- .20 is an acceptable range (total of 1 1/3 stops), I don't think so. </p>

<p>A good rotary drum with continuous reversal will give +/- .02, occasionally better, assuming that the operators does the right things. The drum system with and eccentric wheel which gives later agitation as well as rotation is much because it tends to give streaky processing.</p>

<p>I wish I could describe the "Dobro" method that we Brookies had to learn from our mentor, Boris Dobro in the 1940's through the 1960's, it gave the best hand processing in a stainless steel reel/tank system, I could show you but I'll be darned it I can describe it in words even though it is actually simple. It yielded +/- .03 (1/10th f stop) in a unimaged 1.00 density.</p>

<p>At Calumet in the old days when the company actually manufactured things, we guaranteed density variation of +/- .02 sheet to sheet and film to film, 1/10th of the so called standard. For special uses with special temperature controlled processes, we would guarantee +/- .10.</p>

<p>I did research on these systems and of course the very best was motion picture spray processing which was +/- .01, or 1/30th of an f stop variability, we did a still version of these for TV shadow masks, and sensitometric processors (which we also made).</p>

<p>Lynn</p>

<p> </p>

<p>How important? That depends on you point of view. If you want to process you film in 5-20 minutes, yes, it's important. If you can let the film sit in the tank for up to 3 hours, then agitation become umimportant, or at least less important. This is called stand developing. I never had much luck with it, but there are lots of photographer who process their film in this manner. You agitate for the first 30-60 sec., then let the film sit there for "x" number of hours. This requiers a very dilute dev., like Rodinal @ 1+300.<br>

Some photographer use semi-stand where they agitiate every few minutes.<br>

The idea of this is to bring out "edge effects" (can't recall actually seeing one) and very sharp negs.</p>

<p>Bill,</p>

<p>That's basically the routine I use; apart from the longer agitation in the beginning<br>

erwin</p>

<p>I can back up, with my own limited powers of determination, what Lyn says about spinner type plastic tanks and reels. I always use the spinner with these, in pretty much the same way he described, and the results are remarkably consistent. </p>

<p>99% of the problems that people have with streaking and so called surge marks are in improper or not sufficiently agressive agitation with the first 60 sec being the most important.</p>

<p>People who pour developer into a daylight tank are asking for trouble. The wet/dry edge must meet the developer and proceed across the film quickly and without retreating. </p>

<p>Of all the agitation schemes I have tried over 50 years, the most agressive yielded the best results. As soon as i read help, I am doing nice slow gentle agitation and i am still getting uneven results, I know the problem.</p>

<p>I have tried stand with diluted developers, and although the pics may look streak free, the exposed leader is full of streaks which raised suspicions about the pics. Agitation removes bromide developing byproducts that lead to streaking.</p>

<p>Don`t know about Drobo, but invert while twisting, upright while twisting, repeat again was how I was tought in 1960. Never got marks. </p>

<p>Bill Pierce wrote in Modern Photography of his method about 1964. Use a double size tank with top reel empty, fill with enough developer to cover the only the bottom reel with the film. Roll 400 degrees, reverse 400 degrees and repeat for a total of 1600 degrees. Stand the tank up between rolling cycles. This works like a charm.</p>

<p>You can find Bill at the Rangefinder forum today as an accomplished full career photojournalist.</p>

<p>Ronald that is where a nice presoak comes in. I know some don't like to do that and others say it is a waist of time but I presoak most films..... Just my method.. does not have to be anyone elses</p>

<p>Larry</p>

<p>I use the inversion method - six inversion in the first 30 seconds, then one inversion every 30 seconds after that. And I pre-soak.</p>

<p>Erwin - I would never try to discourage experimentation because, if done carefully, you will always learn something even if only "well I won't do that again". For me, the primary role of agitation is to assure even development so I consider it extremely important. Unfortunately, problems are not always immediately evident. In your still life scene uneven development may or may not be obvious. But your proposed setup may be very good at demonstrating changes in negative contrast due to changes in agitation. Suggestion: first confirm your development routine produces evenly developed negatives. How: expose several frames throughout your next role to a clear blue overhead sky and print each at your usual size. If the prints show a relatively even tone you know your system is humming right along. If not you know you have a problem with your negatives or your enlarger. I determined an agitation pattern and frequency that produced not perfect but satisfactory evenness and limited my variables to exposure and development time.</p>

<p>Rick ,<br>

Thanks for your input. If the sky permits it, not too cloudy, I'll get some pictures of the sky inthere<br>

Actually I wasn't planning on printing any of them just study them at a light table or maybe contact prints That's why I intend to do the test with 120.<br>

To all the others also a big thank you for your insights.</p>

<p>

<p>

<p>

<p>How important is agitation? Very important.<br>

Whatever you do for processing, do it consistently. Stay with one temperature, one agitation plan, one dilution for your developer etc. That rules out the "a third one will have erratic and slightly random agitation" scheme. Don't bother with any erratic scheme; it will cause you endless trouble. Do your darkroom in a repeatable way so you can diagnose any errors that come up.<br>

In general, the less you agitate, the longer you need to develop. If you agitate less, the highlights will exhaust their developer relatively quickly, and allow the shadow areas to develop a bit more than proportionately. This goes most with very dilute developers and very long development times. The extreme in diluted developer and minimal agitiation is known as stand development, since you let the film "stand" in the developer nost of the time. Stand development can go on for one or two hours or more. It can be prone to some problems with uneven development.<br>

The other extreme is one or another maximum agitation scheme. Constant agitition will build highlight density fastest.<br>

But whatever scheme you use, make a system and stick with it so you can alter just one variable at a time to get the results you want.<br>

Best,<br>

C</p>

</p>

</p>

</p>

<p>Along with agitation you need to consider how much air space you leave in your tank. Rather than a full single reel tank I use a double tank with one reel and air space in the tank. Seems to work OK for me with PMK pyro developer. You will probably find people using many different agitation and air space methods and all having results they are happy with. Best to stick with one method unless you have a problem. Then research a method people have used to solve your problem. </p>

I'd like to know how agitation affects grain. Anyone has ezperiences?

<p>I like to use a high-contrast developer recipe, and I think the influence agitation has will be relative to the composition of the developer. For a "gentler" developer, like a Metol-only D23, I'd say it would have much more bearing. For the recipes I use, temperature seems to be a more powerful, volatile influencing factor than agitation.</p>

<p>An accurate thermometer is of equal importance as agitiation, the non-adjustable glass 'color thermometer' from Paterson (about 12" long) could be a good investment for anyone. Re: agitation - first 30 seconds, two light taps, then each following minute I give one gentle "swoosh" level rotation, then 2 inversions and two taps over approx. 8 seconds.. works for me.</p>

<p>I went ahead and tested it.<br>

I made a few changes to the test as I described it in the first post:</p>

<ul>

<li>I only did the test with three films (I was out of HP 5+)</li>

<li>As for agitation I dropped the "Random" one.</li>

<li>The one with full agitation was done by an old jobo cpe I have on the high speed.</li>

<li>Further conditions where the following:

<ul>

<li> Developer was Rodinal at 20°C 1+25</li>

<li> Developing tank was a Jobo 1521</li>

<li> Filling was complete with 470 ml of solution</li>

<li> In order to not have to prepare the solution for each roll I prepared 750 ml of solution and reused this each time figuring that the 250 ml unused solution is more than enough to replenish.</li>

<li>The scene was metered using my D80 both on centerweight and matrix and I settled on 1/4 and f 5.6</li>

<li>for each roll I shot the first 6 frames on the settings (1/4 - 5.6) the rest was done on equivalent settings; 1/8 f4 and so on.</li>

<li>Shooting was of course done on a tripod.</li>

</ul>

</li>

</ul>

<p>The first roll I developed was done in stand developing 6 minutes. The second one was done on the jobo with full 6 minutes agitation. The last one was 'my' standard way of developping 30 seconds of agitation and then 10 seconds every 60 seconds.<br>

I don't have a scanner yet so I cannot show you the results.<br>

I'll make a few prints and scan try to scann these at work in the coming days and show them.<br>

As for the results the 'stand' roll has reasonable images on it be it they are on the light side. (looks like 2 stops under exposed). They look very printable however.<br>

Both other rolls are virtually indistinguishable.<br>

These results lead me to believe the following:</p>

<ul>

<li>Agitation is important </li>

<li>Above a certain amount agitation It does not matter any more </li>

<li>The scheme you use does not matter as long as you agitate enough.</li>

</ul>

 

<blockquote>

<p><em>Along with agitation you need to consider how much air space you leave in your tank. Rather than a full single reel tank I use a double tank with one reel and air space in the tank.</em></p>

</blockquote>

<p>Chuck,<br>

I did that once but with rodinal it's not such a good idea. It will foam and you will see the pattern of the foam in the lighter parts of the negatives.</p>

<p>Erwin</p>

<p>Thanks for the headsup on that Erwin...I havent used my Rodinal yet but will be soon so this info may have saved me a lot of grief.</p>