Perplexed about agitation--recommendations vary widely.

[lesged]

I have scanned this forum regarding agitation and have found such

wide variety of techniques used: constant agitation at beginning then

few agitions every 30 sec or minute. I've been the Rip van Winkle

away from b&w for many, many years and when I awoke, I was giddy with

all the new films and developers and tried so many combinations with

limited degrees of success.I've settled down to use two new films:

Ilford's Delta 100 and the new Tri-X in 35mm and 6x6 format. Tanks

are s/s Nikor type for inversion agitation, sizes: 1,2 and 4- 35mm

s/s reels (latter two equal 1- 120 and 2-120 reel.) minminum volumes

of chemicals are: 250cc, 375-450cc and 850cc, respectively.

Developers I have been using are D-76, FG7, Xtol and home brew

Beutler. Also have Paterson tanks in similar sizes.

 

What agitation would you recommend? I used to use 5 sec every 30 sec

agitation from initial pour or dunk.

 

Les

[michael_goldfarb]

Yes, this is a highly personal issue, with recommendations all over the map. Everybody's darkroom procedures and experiences seem to differ...

 

In my own case, I have found that you can get by with MUCH less agitation than is commonly thought. While I was on the quest for great Minox negatives (where getting less-visible grain is the name of the game!) I found that I could develop TMX in D-76 1:1 with gentle agitation at 30 seconds, 1 minute, or 2 minutes - with very little change in the results (including not all that much better grain at 2 minutes). I have gotten similar results with everything else I tried: APX 100, FP4+, PX, TX, TMY... I ended up standardizing on agitation at 1-minute intervals.

 

I have recently switched to HC-110 (because the volume of b/w that I do has gone down dramatically, and I've found myself throwing away batches of D-76 after almost a year), and here I've been using 30-second agitation because development times are so much shorter, and I'm a bit scared of not getting sufficient development otherwise...

 

All I can say is, start with the manufacturer's recommendations, and feel free to experiment. With my own special interest in keeping grain less prominent, I have found that too much agitation is more likely to be a problem than too little - but everybody's experiences are different.

 

What I do think is definitely true is that there is more wiggle-room in agitation practices than is commonly thought. But then, I'm following my dad's (the recently retired 50+ year pro) motto: "An amateur knows how to follow the rules. A professional knows how to break the rules.", and I was raised as a pro!

[dhananjay_n]

The basic trade-off with normal developers is between evenness of agitation and compensation and somewhat different developing times. As you reduce agitation, you get compensating effects but at the risk of uneven development. With staining developers based on pyro or catechol, increased agitation also runs the risk of aeriel oxidation and increased general stain. Some folks suggest that increased agitation rates reduce adjacency effects - Richard Henry reported some testing to disprove this, but I haven't seen that replicated anywhere else (although Richard Henry's argument that adjacency effects are due to developer migration within the emulsion makes a lot of sense). All of this of course assumes that the increased agitation is random agitation - if you agitate in such a manner that you set up flow patterns etc, you will get uneven development.

 

In some tests I had done earlier, I found that the difference in curve shape between continuous agitation and agitation once every 30 seconds was pretty minimal. It was only when you reduced agitation to about once a minute or preferably once in 2-3 minutes that compensating effects became more clearly visible. It should also be noted that these things also depend upon your picture - large, even areas of tone like smooth skies are more likely to show the effects of midly uneven development, rather than na subject with lots of local contrast.

 

Cheers, DJ

[john_cook1]

Everyone seems to have his own style of agitation. As long as it gets the job done, the kind of English you apply to turning over your tank doesn't probably matter. As long as you are consistent from run to run.

 

Your method is pretty standard. My personal favorite (for what it's worth) is five quick inversions in five seconds at the top of each minute. Simply because I was taught (first) to agitate sheet film only once per minute instead of every 30 seconds.

 

My only caveat is to get it over-with as soon as possible. Very slow, prolonged, agonizingly-gentle agitation movements tend to set up developer flow patterns around the reels which cause plus density at the film edges. As I have been known to say before, purchase a Tito Puente album to help to keep up the tempo. Now and then, everybody needs a little salsa!

[richard_cochran]

Something I've recently discovered is that the amount of

air space in the top of the tank is quite significant. I've

been a practitioner of the "fairly vigorous inversions

ten seconds out of every minute" school, which has usually

given good results. But recently I noticed that some of my

120 negatives were coming out much more strongly developed

at the edges than in the center. I believe the difference

between my evenly developed negatives and my uneven ones

was that the uneven ones were filled with developer to

overflowing, while the evenly developed ones had a bit

of an air space in the top of the tank, so the

agitation really sloshed things around.

<p>

The only thing I'll say for certain though is that you

should find a method that works for you and stick with it.

Pay attention to the details, including the level to which you

fill your tanks, and keep things consistent.

[johnmarkpainter]

Les,

 

The main thing is to find a method and STICK TO IT for a while so that you can have

consistent results.

 

I always do 1 full minute of agitation at the start of development and then I do 10

seconds every minute. I have quit inverting because I got tired of getting chemicals

on my hands when the tank would leak....I just use the little twister thingy.

 

jmp

[jorge_oliveira2]

I think it becomes clear that if there are so many different viewpoints on agitation, it's because it's very non-critical...

 

As long as you do some - from 30s to 2min would be the typical range, it shall be OK.

 

I've choosen 2 min for two reasons:

 

I like some compensation (a bit is better than none; I use only 35mm)

 

It give me time do to some small chores - like washing used measuring cups, etc between agitations.

 

Note; I've purchased a cheap down counting timer (used for cooking). It beeps at 2 min; it makes life at the laundry, er lab, easier.

[rick_jones5]

Lester - I struggled with this issue and fought it tooth and nail until I finally got the upper hand. So what did I learn: the primary goal for any agitation scheme is to achieve as even development as possible. "As possible" because I don't believe truly even development can be achieved in small tanks with spiral reels-but we can come close enough for government work. Also I believe the actual mechanics of agitation are of little consequence as long as you are getting even development. Sooooo! do yourself a favor and shoot a single roll of a clear North sky(try a Zone V exposure), develop and proof. Look at the proof carefully and critically. Are you seeing a nice smooth even density? If so ask no more questions about agitation and just do your thang. Then again, if you see more density (lighter in the proof)on the edges a new scheme is in order. Just as Richard C. mentioned, for me a generous air space in my 32oz s.s. tank seemed to be very important (26oz developer, more or less, in 32oz tank) in solving my problems. I also configured the reels so there was little or no movement within the tank. Initial 30 constant then 10 sec(3 inversions) each min. One inversion is inverting the tank with a twist and returning to upright. I also never pour the dev into a tank with film. I drop the film into a dev filed tank. But most important of all - IF IT AIN'T BROKE DON'T FIX IT!

[mike_scarpitti]

The following general points are beyond dispute:

 

For 35mm work, where acutance is important and edge effects must be preserved, minimal agitation is advised. I use single-shot acutance types of developers (Paterson Acutol, for instance) and process & agitate in the following way:

 

I first fill the tank with water at the same temperature that I'll be developing at (usually 68F) for at least 5 minutes. This allows the film to become fully saturated and helps even out development.

 

After draining the tank, I fill it with developer and immediately begin agitation for about 30 seconds. This consists of inversions and simultaneous roatations, all performed gently. The tank is then rapped firmly but gently on the table to dislodge air bubbles.

 

Beginning at the top of the succeeding minute and for all successive minutes, I agitate ONCE per minute, with TWO inversions/rotations in rapid succession, totalling no more than 5 or 6 seconds of agitation per minute.

 

I use a water stop bath, begun about 30 seconds before development is supposed to end, etc.

[lesged]

I thank you all for your comments and suggestions. As I a newbie to this forum, I'm impressed with the generous helping hand spirit and the high quality of responses from so many serious photographers. I know I have to eliminate as many variables as possible and to stick to the two films I mentioned till I "master" them.

 

One variable that puzzled me completely was why I got such flat, dense negatives with a variety of films--which I overcompensated by developing way beyond any published times. The problem was an error in my dial thermometer. I finally compared it to my 14" mercury laboratory quality thermometer that has been hibernating in its protective tube in my darkroom for decades. The dial bi-metal themometer was 6 deg F lower than the mercury one. I remember dropping it on the concrete floor once (or was it twice?) I bought a new dial one that is adjustable and check it from time to time against my trusty standard.

 

Les

[john_hicks___]

First of all, I found that if sufficient agitation is given for very good evenness there's no difference in curve shape between that and continuous agitation. None! See http://unblinkingeye.com/Articles/Rotary/rotary.html for info.

 

Second, to the best of my ability to see, I don't see any significant difference in acutance or edge/adjacency effects between intermittent agitation and continuous agitation. This echos Henry's findings. Now, I don't doubt that there's a difference between very-minimal agitation and continuous agitation, but since very-minimal agitation results in poor evenness, it doesn't matter. I find a _far_ greater difference in acutance between using two different types of developers, say, Rodinal and D-76.

 

For intermittent agitation, I recommend a half-full tank; that is, use a double-size tank, put a loaded reel on the bottom and an empty reel on top, and use only enough developer to cover the bottom, loaded reel. Give 30 seconds initial inversion agitation and five seconds inversion agitation every 30 seconds. INVERT THE TANK VIGOROUSLY! You certainly aren't going to hurt anything or make the film blurry. Doing a magical gentle pattern while murmuring sweet nothing is BS and only gives bad evenness.

 

Others have mentioned having a big air space in the tank; it's essentially the same idea. I used to do up to three rolls in a four-reel tank, seven rolls in an eight-reel tank etc. The idea is to _force_ the developer to move over the film surface. Conversely, a stuffed tank prevents liquid movement. Think of baffles in a big, flat water or fuel tank in a boat, that prevent the liquid from sloshing back and forth.

[mike_scarpitti]

<i>"John Hicks -- , oct 18, 2003; 11:04 p.m. First of all, I found that if sufficient agitation is given for very good evenness there's no difference in curve shape between that and continuous agitation..."</i><p>

 

<i><b>(Moderator's note: Above quote was edited for space and clarity. It isn't necessary to quote entire messages verbatim.)</b></i><p>

 

First of all, I'm speaking primarily about 35mm. Are you? Secondly, far less agitation is required than is usually given if evenness is demanded. The perforations of 35mm film cause streaking if agitation is too vigourous. Keep it on the gentle side.

[mike_scarpitti]

Beutler requires more frequent agitation than solvent developers as it is near exhaustion constantly. Solvent developers are not as critical on agitation. The move dilute the developer, the more likely streaking may appear unless gebtle, moderaste agitation is given.

[lesged]

Thank you John and Mike. I've gained a much richer appreciation of what goes on in the tank when it shakes, rattles and rolls. You two and the others before, have all shared your knowledge and experience and I'll try to put much of what I've learned to use starting with the very next roll. My Burke & James bulk winder has just given up its last 28 exposure to a reloadable cartridge of HP5 plus. Its empty tummy awaits supper which will be 100 feet of new Tri-X 400TX.

 

Be assured that new film for me, will be agitated with great respect. That I promise.

 

Thanks everyone.

 

Les

[mike_scarpitti]

I want to emphasize that I have found that most beginners over-agitate, and that two gentle inversion/rotation cycles in immediate succession once per minute give me both excellent evenness and good sharpness with high-acutance developers like Acutol. I expect HC110 should be handled similarly. Solvent developers may differ slightly in the amount and frequency of agitation required. Twice per minute agitation is probably verging on excessive for 35mm, and once every two minutes would probably not hurt, but I split down the middle.

[chris_waller]

I use Rodinal as my prinicpal developer, but that doesn't make any great difference in itself. I pre-soak (opinions vary on the benefits of that) for 2 minutes in water at 20 C. I give about half a dozen inversions, tap the tank to dislodge any air-bells, then let it stand. Then I pour out the pre-soak and pour in the dev, inverting the tank 4 times in the first 30 seconds. Then I give one inversion every 30 seconds after that. Prior to each inversion I give the tank a half-turn as it stands on the bench, relying on the inertia of the liquid to effectively give some movement in the horizontal plane. This latter is probably a vanity but it makes me feel better!

[john_hicks___]

> First of all, I'm speaking primarily about 35mm. Are you?

 

35mm through 8x10.

 

> The perforations of 35mm film cause streaking if agitation is too vigourous. Keep it on the gentle side.

 

If your agitation is replacing all the developer at the emulsion/liquid interface during each agitation cycle, _which is the intent of agitation_, then it's impossible to have more replacement caused by sprocket holes. If the sprocket holes are causing streaks of higher density then obviously the agitation over the entire surface of the film isn't enough.

 

Anyway...enough about this; back to the original question.

 

The only to test evenness is to photograph an even tone..a grey card, clear sky etc...develop the film and, preferably, read areas of the entire neg with a densitometer, or at least make a print, giving the paper continuous agitation to try to avoid introducing artifacts there.

 

If your agitation method is giving sufficient evenness then don't change a thing. If it isn't, then most likely you need to increase the vigor or amount by which the film is moved through the developer. If that change makes things worse then agitate less vigorously; if that change makes things better than keep on doing it. Only _YOU_ can decide if your agitation method is giving sufficient evenness, and only you can decide whether some much-touted method is better or worse than what you're doing.

[david_goldfarb]

And just when you thought everything has been said on this topic, has anyone ever encountered the <a href="http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=2959724866&category=629">Vokar Film Agitator</a>?

[mike_scarpitti]

To John Hicks:

 

You don't want violent agitation. It is certainly possible to over-agitate. Agitation methods are specified and described by ASA, etc.

[lex_jenkins]

That's pretty funny, David! I've recently considered ways to hook a timer to a vibrator for exactly this purpose. For example, to agitate every half-hour during stand processing.

 

Anything I can think of, including shoving a half-full can of beer up the butt of a whole chicken during barbecuing, someone's beaten me to it and marketed it for $4.49 at Wal-wart.