Agitation, surge, and uneven development?

[koraks]

Sorry Matt , all links I had to this issue are dead now. Author GEORGE POST exposed 200 rolls of 35mm Plus X and processed it using various tanks and methods of agitation.
I'm not aware of anybody who did this level of research on the subject.

@MattKing forwarded a pdf to me; it's kind of poor quality (image, non OCR) and the critical bits are kind of difficult/tiring to read. I've summarized the key information from the pdf below. The table towards the bottom is a literal quote of the original work. The brief notes preceding it are my summary of the accompanying text.


Source: "Shake it Up - The ups & downs and ins & outs of 35mm film agitation", George Post, Darkroom Photography, March-April 1986, pp. 20-26
----------------------------------

Purpose: find out what agitation method works best and why.

Materials: Kodak Plus-X, Kodak D76 1+1 (Kodak donated 100 rolls). Nikon F3 @ 1/125, Nikkor Micro Nikkor 55/3.5 @ f/4.

Metal tanks: two-reel 16oz. Omega, four-reel 32oz Nikor

Plastic tanks: Paterson, 2-reel and 5-reel Super System 4

Test setup: light box with collection of ND gels and opaque disk on top to create various densities ranging 1-4 stops. Unfiltered light box set at zone IX or +2.5 stops. f/4 @ 1/125s with MLU. Unused area on light box masked off and room lights off to cut flare.

Film loaded onto reels and reels into tank to ensure known orientation.

‘Moderate agitation’: flip tank at one second, flip back up at next second.

‘Vigorous agitation’: flip round and back up on the same second.

Each test preceded by 1 minute pre-soak against bubbles.

Process:

• Presoak, 1 min 68F
• Development 8 min intermittent agitation, 7 minutes constant
• Stop 30 sec.
• Rapid fix 2.5 mins.
• Water rinse
• Hypo clear 2 mins.
• Wash 5 mins.
• Photoflo
• Sponged off, hung to air dry

Contact printed to Polycontrast Rapid IIRC heavy magenta filtration. Visual inspection and densitometry (RH Products B&W Densitometer) on frames 1, 18, 36

Conclusions

• No, minimal, moderate agitation: unacceptable streaking and mottling
• Repetitive flow patterns like rotation: directional streaking
• Rotary: lengthwise streaking
• Sprocket hole streaks commonly occurring
• Vigorous & constant rapid multi-form agitation produce most even results. Vigorous = 5 inversions, 1 inversion per second, every 30 seconds. Twist or no twist makes no difference.
• Plastic Paterson tanks gave best result due to lid design leaving air on top, but Nikor tanks were used entirely full with no air on top. Filling them only to cover the reels improved results.
• Frames close to core/column more prone to artefacts. Rotary: more development on the outer windings of the reel than close to center column (up to 0.10-0.15 logD difference).
• Large metal tanks full of reels: upper reels more prone to fill streaks.
• Paterson tank prone to fill streaks on bottom roll due to center column design
• Rotary: metal reels more prone to excess edge density than plastic Paterson reels
• Presoak helped with uniformity especially with some photoflo added to presoak to get rid of bubbles

Agitation methods & results:

Method	Description	Rating	Comments
No agitation	Fill, rap & let tank sit	Horrible	Severe non-uniformity, streaking
Minimal inversion	2 slow inversion cycles @ 2 sec each per minute	Fair (Paterson), poor (stainless)	Heaving streaking and mottling. These methods are insufficiently turbulent to produce uniformity in heavily exposed regions of the film
Moderate inversion	3 slow inversion cycles @ 2 sec each per 30 sec.	Fair (Paterson), poor (stainless)
Moderate with a twist	Same as above; tank is also rotated ½ turn during inversion and another ½ turn as it’s return to upright	Poor (Paterson & stainless), (Fair if agitation is continued for first 30 sec of development period)
Vigorous inversion	5 quick inversion cycles @1 sec each per 30 sec	Excellent (Paterson), Good (stainless)	Very even, uniform development. Slight streaking & non-uniformity
Vigorous inversion half full	Same as above, but with SS tank only half full of developer, film on lower reels only	Excellent (SS only)	Airspace due to new lid design in Paterson tanks seems to improve turbulence. This method was an attempt to achieve a similar effect in a stainless tank
Vigorous inversion with a twist	Same as “vigorous inversion”, but tank rotated ½ turn during inversion and another ½ turn as it’s return to upright	Excellent (Paterson) Good (stainless)	Good uniformity Fair uniformity, noticeable excess edge density
Paterson method (from Paterson Super System 4 Tank instruction sheet)	At start of development, reels are given several left & right vertical rotations with plastic agitator; then tank is rapped, covered, and given 1 inversion cycle per minute	Fair	Moderate mottling & streaking, probably due to insufficient turbulence
Vertical rotation	Alternating rotation around vertical axis 5 sec per ½ minute. Tank standing upright.	Poor	Lengthwise streaking, excess edge density (especially stainless)
Horizontal rotation	Tank rolled back & forth on countertop 5 sec per ½ minute	Fair (Paterson) Poor (stainless)	Reasonable uniformity, slight lengthwise streaking) Strong mottling, excess edge density, lengthwise streaking.
Constant horizontal rotation	Tank rolled back & forth on countertop, reversing direction every 4 seconds	Poor	Lengthwise streaks, poor uniformity, excess edge density
Constant horizontal rotation (half full)	Same as above, but with tank only ½ full of developer	Poor	Strong lengthwise streaks, poor uniformity
Constant slow multiform	10 sec of slow inversions, 10 sec of horizontal rotation, 10 sec of up & down “cocktail” shake, then repeat continually	Fair (Paterson) Poor (stainless)	Slight streaking, non-uniformity Pronounced non-uniformity and excess edge density
Constant rapid multiform	5 sec of quick inversion, 5 sec. of horizontal rotation, 1 sec of up & down “cocktail” shake, then repeat continually	Excellent (Paterson) Good (stainless)	Faster alteration of direction appears to randomize turbulence. Slight excess edge density with stainless.
Dunk & pump	In total darkness, film lowered into prefilled tank with T-bar, agitation by pumping reels up & down constantly first 15 sec & 3 times each 30 sec thereafter	Fair (Paterson) Poor (stainless)	Minor streaking across film, poor uniformity Pronounced sprocket hole surge
Dunk & pump & turn	Same as above, but reels are also rotated in alternating directions as they’re pumped	Good (Paterson) Poor (stainless)	Better uniformity than above Less sprocket hole surge than above, but worse uniformity

 

[koraks]

Apologies; the table doesn't display well. Here's a screenshot of the same table:

 

[Chuck_P]

Apologies; the table doesn't display well. Here's a screenshot of the same table:
View attachment 381866

Wow that's quite an extensive study. I wonder if the SS tanks that use the plastic lid would've performed with the "Good" rating as well. I've always used the plastic lid on my SS tank and have always been quite satisfied. But I guess I need to expect that it's possible I haven't recognized some of those anomalies that were stated with the Nikkor SS tank.

 

[runswithsizzers]

Thanks to @gorbas, @MattKing and @koraks for your combined efforts to share the results from this study; interesting! I do wish I could see photographs of what George Post is calling "excess edge density" -- is it a very narrow band of density with relatively hard edges? Or is it a longer, smoother graduation of density extending from the edge and fading out into the central area of the frame?

And I wonder if conclusions about test results done with 135 film can be extended to 120 film?

I never noticed the edges of my 35mm negatives exhibiting the same density pattern I am seeing on my 120 film, even though I am using the same agitation (more-or-less). Looking back at some of my 35mm negatives, I just can't find any examples that clearly demonstrate the kind of increased edge density which I am seeing on my 120 negatives.

I just developed two more rolls of Tri-X 120 in my 32 oz tank, but with more vigorous and longer agitation than what I have been using. I have not tried to print any of the new rolls yet, nor have I had a chance to carefully examine the scans, but a quick look at the negatives on a light table suggests there was no improvement. (Unfortunately, I am seeing a new issue, but that's another story.)

What I changed:
Previously: one agitation cycle = a 1/4 rotation twist, then a slow inversion to upside-down and back again, taking about 2 seconds per cycle.
Initial agitation: continuous for 30 seconds
Subsequent agitation: 2 agitation cycles per minute, taking about 4-5 seconds of each minute.

This last time: one agitation cycle = a quick inversion combined with a 1/2 rotation twist, a one second pause, then a quick return to upright while twisting again.
Initial agitation = continuous for 45 seconds
Subsequent agitation: 5 agitation cycles every minute, taking 10-12 seconds of each minute.

In both developments, I left about 1/2 inch of air space in the tank, and the two reels were allowed to slide up and down about 1.5 inches with each inversion.

 

[ediz7531]

Apologies; the table doesn't display well. Here's a screenshot of the same table:
View attachment 381866

This is an interesting study. Does the article author mention if the reels were loaded into a tank full of developer in the dark or whether the reels were loaded in the tank first and then developer was poured in? The latter can take much longer - reading Anchell and Troop I gather they claim this can introduce inhomogeneities early on thus they advocate for a longer initial agitation.

 

[koraks]

Does the article author mention if the reels were loaded into a tank full of developer in the dark or whether the reels were loaded in the tank first and then developer was poured in?

Yes, he specifically tested this. He observed that fill streaks are a real issue esp. on the stainless tanks he used and that dunking the film & reels into the pre-filled tank in the dark also gave evenness problems, but of a different kind. On the plastic Paterson tanks he also observed fill-related unevenness on the bottom-most roll in the tank which seems to relate to the fill funnel/center column design and interactions with the lower row of sprockets on the film. Ultimately, the answer to these problems appears to be to introduce a pre-soak, at least that's what I conclude from this article and the results & conclusions presented in it.

 

[Augustus Caesar]

Apologies; the table doesn't display well. Here's a screenshot of the same table:
View attachment 381866

Did you fill the Paterson tanks fully?

 

[koraks]

Did you fill the Paterson tanks fully?

Please give this thread another thorough read before commenting.

 

[gorbas]

Did you fill the Paterson tanks fully?

Take glass jar, fill it fully with water, close and agitate it. Note motion of water in it. Now take bit of water out, agitate it again, note flow patterns. Think!

 

[runswithsizzers]

Take glass jar, fill it fully with water, close and agitate it. Note motion of water in it. Now take bit of water out, agitate it again, note flow patterns. Think!

If there is nothing else in the jar except water, this is a valid point (although one might need to define "a bit of water" more precisely).

However, as mentioned in my post #52 the SS reels I have - when put into the SS tanks I have - can move up and down when the tanks are inverted. In other words, even if the developing fluid does not move much in a full tank, the spiral reels move within the fluid. I am trying to work out in my mind if there is any predictable difference between moving the liquid over stationary reels or moving the reels through stationary liquid?

In my case, I usually do not fill the tank completely, so both the liquid and the reels are moving with each inversion.

 

[koraks]

I am trying to work out in my mind if there is any predictable difference between moving the liquid over stationary reels or moving the reels through stationary liquid?

The way you formulate it, doesn't matter - the reels and the liquid move in relation to each other.

What does matter is in an entirely full tank, the motion of reels sinking to the bottom when the tank is tilting is likely to produce a more laminar flow across the film surface. This effectively means less agitation than if the flow would be more turbulent. The flow will in practice be turbulent if there's some air/space left on top of the liquid volume inside the tank. @Augustus Caesar has repeatedly stated that he does so. Effectively this means that his way of working will give more or less the same qualitative and quantitative degree of agitation as in a tank that's only filled enough to just cover the reel(s) present. Concerning the story about the bubbles - I don't see how filling the tank nearly to the top vs. covering the reels with a small margin will make any difference in terms of bubble formation, persistence etc. I've also never noticed a difference in my own practice.

 

[Loren Sattler]

Here are some comments I posted about this subject in 2007 on this forum:

"For several years, I fought uneven development with 120 film in a single roll stainless steel tank. I thought I was helping the uneven development with less agitation. I got to the point of just swirling the tank slightly at 30 second intervals. Someone on a forum suggested that insufficient agitation caused the uneven development, and I concur.

Read Kodak's typical agitation instructions (page 4 of 12):http://www.kodak.com/global/en/professional/support/techPubs/f9/f9.pdf

These instructions call for "5-7 vigorous inversions every 30 seconds". I switched to this method and rarely see any uneven development with Tri-x 400 and Plus-x films. Contrast increases. My standard development time (for a condensor enlarger) is about 85% of the suggested time."

At the time I was having more issues with Plus-X film than Tri-X, so all films are not the same. What I found was that vigorous agitation was the solution. I use SS reels and tanks and invert 6 full inversions in 5 seconds. (That is 12 180 degree motions in 5 seconds which is a very rapid rate). Developer is D76 1:1, Tri-X and T-Max films exposed 1 stop over box speed, then developed at about 85% of recommended time for "normal" contrast (bright light, but not direct sunshine and also flash).

Here is a current link to Kodak technical paper on development including agitation: https://www.digitaltruth.com/products/kodak_tech/AJ-3_How-to-Process.pdf

 

[Loren Sattler]

Also, I pre-soak film. My purpose is to better control temperature of the developer.

 

[Loren Sattler]

Here is a link to the February 2007 forum:

uneven development.

Hi, I don't know how I have suddenly developed this problem because I think I do everything the same like before -- and I didn't use to have this problem. I have 2x 35mm reel paterson tank and I have been lately getting uneven development to the film on the top reel. Uneven underdevelopment...

www.photrio.com

 

[runswithsizzers]

Here are some comments I posted about this subject in 2007 on this forum:

"For several years, I fought uneven development with 120 film in a single roll stainless steel tank. I thought I was helping the uneven development with less agitation. I got to the point of just swirling the tank slightly at 30 second intervals. Someone on a forum suggested that insufficient agitation caused the uneven development, and I concur.

Read Kodak's typical agitation instructions (page 4 of 12):http://www.kodak.com/global/en/professional/support/techPubs/f9/f9.pdf

These instructions call for "5-7 vigorous inversions every 30 seconds". I switched to this method and rarely see any uneven development with Tri-x 400 and Plus-x films. Contrast increases. My standard development time (for a condensor enlarger) is about 85% of the suggested time."

At the time I was having more issues with Plus-X film than Tri-X, so all films are not the same. What I found was that vigorous agitation was the solution. I use SS reels and tanks and invert 6 full inversions in 5 seconds. (That is 12 180 degree motions in 5 seconds which is a very rapid rate). Developer is D76 1:1, Tri-X and T-Max films exposed 1 stop over box speed, then developed at about 85% of recommended time for "normal" contrast (bright light, but not direct sunshine and also flash).

Here is a current link to Kodak technical paper on development including agitation: https://www.digitaltruth.com/products/kodak_tech/AJ-3_How-to-Process.pdf

@Loren Sattler, thanks for posting. BTW, your first link gives me a "404" error.

I would be curious to know, do you fill your tanks completely, or do you leave some amount of air space?

In the Kodak Publication in your second link (How to Process and Print Black-and-White Film, February 2016 • AJ-3) Kodak does not specifically say how full the tank should be. In other publications* Kodak say to: "1. Fill the empty tank with developer," and ... carefully place the loaded reel into the developer solution."
* from KODAK PROFESSIONAL XTOL Developer - February 2018 • J-109; and these instructions are repeated in the D-76 Data Sheet.

Ilford does not say that the tank should be filled, but only, "The solution volume must be enough to cover all the spirals used."

 

[Loren Sattler]

When I process a single roll of 120 the tank is full or near full. I do not know the capacity of the tank or measure the quantity of D76 precisely. When processing two rolls in a tall tank the quantity is enough to cover the two rolls but not enough to fill the tank. There is both air at the top and the rolls slide significantly in the tank as I agitate (probably slide one inch or so). I do not notice any difference in the negatives when processing one or two rolls of film.

 

[Loren Sattler]

By the way, I get the same error message when trying to open the old link. But, the information on agitation in the newer technical data sheet referenced is the same as the old link.

 

[ediz7531]

If there is nothing else in the jar except water, this is a valid point (although one might need to define "a bit of water" more precisely).

However, as mentioned in my post #52 the SS reels I have - when put into the SS tanks I have - can move up and down when the tanks are inverted. In other words, even if the developing fluid does not move much in a full tank, the spiral reels move within the fluid. I am trying to work out in my mind if there is any predictable difference between moving the liquid over stationary reels or moving the reels through stationary liquid?

In my case, I usually do not fill the tank completely, so both the liquid and the reels are moving with each inversion.

In a 32 oz ss tank I tend to get some edge density - only noticeable in bright skies - on my 120 negatives after developing if I try to develop two rolls at once. That’s using around 800ml of chemistry so there is still plenty of air inside. However, when I develop just the one roll in the tank - so there is one loaded reel at the very bottom with a 120 and a 35 empty reels on top - and using about 500ml of chemistry, I get very even development . I gather that the 32oz tanks aren’t great at enabling suffficient turbulence, so being half empty really helps it in this regard. This seems to match the nice article from George Best that Koraks summarized - although the article tests 35mm film only.

 

[runswithsizzers]

In a 32 oz ss tank I tend to get some edge density - only noticeable in bright skies - on my 120 negatives after developing if I try to develop two rolls at once. That’s using around 800ml of chemistry so there is still plenty of air inside. However, when I develop just the one roll in the tank - so there is one loaded reel at the very bottom with a 120 and a 35 empty reels on top - and using about 500ml of chemistry, I get very even development . I gather that the 32oz tanks aren’t great at enabling suffficient turbulence, so being half empty really helps it in this regard. This seems to match the nice article from George Best that Koraks summarized - although the article tests 35mm film only.

Thanks for sharing your experience. It does seem to me that I never noticed the edge density issue until I started developing two rolls of 120 film at the same time in a 32 oz tank.

If I have only one roll of 120, I normally use a 16 oz tank. After taking a second look at those single-roll results, I can say they definitely show less edge density than do those rolls which were developed two-at-a-time.

I hate to give up the convenience and time savings of processing two rolls together, but I might have to if I can't get more even results.