Do rotary processors affect how the film looks in the end? (tonality, film speed / shadow detail, etc.)

[albireo]

Out of all the photo communities on the internet, Reddit's AnalogCommunity has some of the highest percentage of false information. They have a sub dedicated to making fun of them, AnalogCircleJerk, which I find entertaining.

I don't know.. If AnalogCommunity is dumb, that CircleJerk community is a million times dumber. It was fun at some point, but now it's basically people who hate on people who own or use a Leica. Loads of sour grapes. This 'red dot' pro/against obsession is something I just can't fathom.

Also, I find that r/AnalogCommunity posters who are simultaneously heavy /Circlejerk posters contribute some of the highest amount of false information to that community.

 

[Cholentpot]

This whole setup looks intriguing, it's cheap and accessible. For films with long development times, 10min+ this can really help things out. Are people doing this with multiple rolls of film or only one?

 

[loccdor]

@albireo Sure, any counter-criticism or irreverence can always be too broad or go too far. I just pop in there briefly to smile when I've been seeing too much of people taking themselves very seriously.

 

[GregY]

You can even do rotary processing with steel reel tanks - but if the tank is steel as well, you may be bothered by the infernal racket!
View attachment 407076

or you can just roll the tank on the counter continuously which i do when i use my 5 or 8 reel tanks

 

[xkaes]

I've got to throw in another (for me anyway) BIG plus for tube processing -- with sheet film anyway (and, of course, prints).

So little chemicals are used, each piece of film (or paper) gets FRESH chemicals -- and it saves a lot of money. That's not just the Jack Benny in me -- it makes disposal simple.

 

[Paul Howell]

I have a motor base and Unicolor film drums and reels, I just processed 2 rolls of Foma 400 in MCM 100. I use motor base and drum as the time for Foma 400 is 18 mins at 68 degrees. with the motor base I can shave mints off the time and don't need to watch the timers for agitation. Over the years I have not noticed any difference in shadow details. I do find using a rotary process somewhat of an issue if using a fast acting developer like DK 50 with a ballpark time of 3 1/2 for most 400 ISO films, taking off another 15 to 20 percent, even with continues agiatation I think the risk for uneven development increases.


















rn

 

[pentaxuser]

It's especially noticeable when trying to develop something like sheet film in a tube, you can get streaks referred to as "bromide drag" ..

Isn't bromide drag the result of lack of rotation/agitation as in full stand development ? Or is the phrase "bromide drag" used to describe a similar effect in terms of appearance but isn't in fact bromide drag at all ?

pentaxuser

 

[DREW WILEY]

I've been developing sheet film in trays for the past 40 years and have obtained perfectly even development with every type of film. The devil is in the details, as usual. I temporarily tried drums for film, and found it a less efficient for me personally (I still use drums for processing color prints).

As far as my own devices go, I can adjust the roller spacing on the bars to accommodate drums anywhere from 8x10 inch capacity to 30X40 inch. A key feature is that one of the rollers is eccentric, so it slightly rocks the drum up and down as it rotates, creating 3-way agitation. And I can set the control for either 1-way or 2-way rotation, over a wide speed range. The drums themselves fill and drain much faster than Jobo drums do;
that's really important when making large prints.

My primary film developer for many years was PMK pyro. It can be problematic in drums, so special tweaks have been developed like Rollo Pyro, or tubes have been used to displace the air with inert argon gas, or some
have simply filled the entire drum volume with developer, which seems rather expensive. Then there are Pyrocat based options, rather than Pyrogallol ones. The problem in general can be too much agitation, combined with too high an RPM. If building your own roller device, keep this in mind, and opt for a gear motor control capable of lower speeds.

 

[mshchem]

Isn't bromide drag the result of lack of rotation/agitation as in full stand development ? Or is the phrase "bromide drag" used to describe a similar effect in terms of appearance but isn't in fact bromide drag at all ?

pentaxuser

I (foolishly) tried to develop 2 sheets of 8x10 Tri-X in a Jobo 2800 series tube on the famous Jobo Duolab. I made 2 big mistakes. First I didn't use enough developer, that drum can hold a pint, more liquid means more random flow patterns. Duolab goes one direction, all I would have needed to do was to take the drum off and give it a good shake, or used more developer (I did this 2nd time worked great)

The failure demonstrates "laminar flow" doesn't need to be static like stand development. My situation was such that the products of reducing silver Br-, I- etc acted to restrain development downstream, i.e. bromide drag.

You need to insure your agitation scheme provides enough chaos that you have even development with no artifacts.

In other words follow the freaking instructions.

Also stand development (a version that used viscous developing agents) was practiced by the US spy guys to increase edge effects etc etc. Unless you are flying over enemy territory (Thunder Bay Ontario ) taking 70mm shots you don't need it.

 

[MattKing]

You can even run into problems with uneven development when you use inversion agitation, if you always agitate in a very constrained, exactly duplicated way.
For that reason I always tell people who are new to this to both invert and rotate the development tanks - you want the developer to tumble ang cavitate through the film. You should be able to hear it gurgle.
It is possible to achieve good results with a less energetic approach, but it takes a lot of attention and care toward adding a reasonable amount of chaos.

 

[grahamp]

I learnt a few things the hard way about rotary development. 1) make sure the tank is level (not the machine) if not using an eccentric rotation, 2) if using a print drum, ignore the suggested volumes and use enough chemistry for the format and number of film sheets.

 

[pentaxuser]

The failure demonstrates "laminar flow" doesn't need to be static like stand development. My situation was such that the products of reducing silver Br-, I- etc acted to restrain development downstream, i.e. bromide drag.

You need to insure your agitation scheme provides enough chaos that you have even development with no artifacts.

So any amount of agitation as long as it is completely repetitive creates bromide drag? So based on this and Matt's comment even regular inversion agitation can create bromide drag?

It's news to me and certainly something that I have never seen mentioned in terms of other than stand development. So, along as semi-stand agitation were to be completely regular, this too runs the risk of bromide drag?

It's a pity that Ilford and Kodak do not warn against this in their instructions for agitation. At least I cannot recall seeing reference to the necessity of randomness

I have been using what can be regarded as "regular/repetitive inversion agitation for the last 20 years and haven't seen this effect of bromide drag

Have I been lucky, perhaps?



pentaxuser

 

[MattKing]

So any amount of agitation as long as it is completely repetitive creates bromide drag? So based on this and Matt's comment even regular inversion agitation can create bromide drag?

It's news to me and certainly something that I have never seen mentioned in terms of other than stand development. So, along as semi-stand agitation were to be completely regular, this too runs the risk of bromide drag?

It's a pity that Ilford and Kodak do not warn against this in their instructions for agitation. At least I cannot recall seeing reference to the necessity of randomness

I have been using what can be regarded as "regular/repetitive inversion agitation for the last 20 years and haven't seen this effect of bromide drag

Have I been lucky, perhaps?



pentaxuser

No.
Bromide drag isn't the only mechanism that results in uneven development.
The geometry of tanks and reels also plays into it, along with agitation patterns. Anything that might cause there to consistently be more "flow" of moving developer adjacent to one part of the negative vs. other parts of the negative can result in there being different amounts of development in different parts of the negative.
And as for providing instructions, this is what Kodak says:

 

[Vaughn]

For testing one's skill in maintaining even development, try the SS sheet film racks and dip-and-dunk into tanks. It is the method I was (and then we) taught at the university for 4x5s. I do not believe it was 'bromide drag', but we called them surge marks along the edges of the negatives, where developer surged thru the holes of the SS film rack. If the agitation was not 'randomized' enough, the film areas next to the holes got more development. Actually just lifting, tilting 45 degrees, then back into the tank a few times was all it took.

In another's words..."In other words follow the freaking instructions." We had SS tanks that held four 4x5 racks -- I did have one student who must have missed class that one day -- they got the tanks filled with the chemicals, turned off the lights, removed the darkslides, and proceeded to develop the film in the film holder instead of the SS racks. They had to re-shoot. I tossed out the holder, but had a couple spare darkslides.

I have not used the SS racks for decades -- some find them handy for reducing scratches on x-ray film that has emulsion of both sides of the film.

I use either Pyrocat-HD or Ilford PQ Universal Developer in the Expert Drums. Usually around a liter developer in the 3005 with 5 sheets of 8x10.

 

[koraks]

So any amount of agitation as long as it is completely repetitive creates bromide drag?

Repetitiveness does not automatically create a laminar flow. The problem that @mshchem refers to is that of laminar flow, which can be summarized/simplified as a liquid flowing relatively slowly across a surface, with the liquid forming more or less discrete 'layers' that don't mix (much). The net effect in film development is that a perfectly laminar flow effectively constitutes little to no agitation. A perfectly laminar flow will however never exist; there's always a degree of turbulence. The problem is that this degree of turbulence will differ in various spots across the entire film surface (roll or sheet). This results in differences in the degree of agitation across the film surface. In turn, this can turn up as variations in the degree of development.

Many factors influence turbulence, including speed and pattern of agitation, but also the surface characteristics of the film as well as the geometry of the reels and the tank.

It's a pity that Ilford and Kodak do not warn against this in their instructions for agitation.

They do in certain places, but instead of boring people with theoretical stories about rheology and fluid dynamics, they just give practical points that will avoid or at least minimize the risk of uneven development as a result of issues like this one.

 

[MattKing]

As I recall it from 1st year Physics so long ago, the study of thermodynamics and fluid flows was a far from simple exploration!
Tumbling ang gurgling is a pretty reliable way to attain the chaos you need though.

 

[abruzzi]

No.
Bromide drag isn't the only mechanism that results in uneven development.
The geometry of tanks and reels also plays into it, along with agitation patterns. Anything that might cause there to consistently be more "flow" of moving developer adjacent to one part of the negative vs. other parts of the negative can result in there being different amounts of development in different parts of the negative.
And as for providing instructions, this is what Kodak says:
View attachment 407106

Interesting...5-7 inversions in 5 seconds is a lot more vigorous that what I generally do. I guess that not a problem if Kodak says so, but I generally do 5 inversions in 10 seconds (one second invert and twist, one second return to upright and twist--5 times. It helps if I have some music on that is 60 or 120 BPM. The scherzo to Beethoven's 9th synphony works well since each measure is 1/2 second, so two measures upside down and two measures right side up.)

 

[mshchem]

I remember at my old job some genius thought that we all needed to be proficient at computational fluid dynamics

My problem with developing the 8x10 sheet film never would have happened if I would have used more developer .

 

[Alan9940]

For testing one's skill in maintaining even development, try the SS sheet film racks and dip-and-dunk into tanks. It is the method I was (and then we) taught at the university for 4x5s. I do not believe it was 'bromide drag', but we called them surge marks along the edges of the negatives, where developer surged thru the holes of the SS film rack. If the agitation was not 'randomized' enough, the film areas next to the holes got more development. Actually just lifting, tilting 45 degrees, then back into the tank a few times was all it took.

I think it takes a special voodoo skill to get absolutely even development with tanks & SS hangers! Over the years, I've come close using a very smooth, slow(ish), even lift-tilt agitation but much prefer my Expert Drums. I do still use the tanks & hangers for minimal agitation techniques with Pyrocat-HD. Funny thing...if you don't agitate as much you don't run into issues like surge marks.