You probably should think about presoaking for a couple minutes.
Are you presoaking the film prior to development?
No.
No. I have standardised with DDX for many years
These are the only films I use.
Within +/- 1 degree
Oh right, because you feed the film into the tank in the daylight. There might be a way to send the film through it the other orientation, but could be a hassle. If I understand correctly, with this tank, the film spool is in a vertical direction. So when a film frame reaches the bottom of the spool it is in a horizontal position with respect to the ground. This is interesting because gravity would not cause materials to sink from the top of the frame to the bottom.
I have experienced pouring marks with steel and plastic tanks and the aberrations always ran parallel to the length of the film. Because film in the Lab Box is oriented the other way, if there were pouring marks they could go in the direction of your examples. Pouring marks might be a long shot, but at least it is something to rule out. I found that presoaking mitigated pouring marks. I assume you could do a presoaking cycle with the Labbox to see if it made any difference.
The tank is actually a Rondinax which iin principle is the same as the Lab box. The spool sits vertically in the tank. Agitation is constant by hand. No tipping/rocking etc
The Lab Box looks like it cannot be inverted or even tipped much to the side and the internal spool is 90 degrees rotated from a typical hand processing tank like a Peterson; is this correct?
Do you rock it from side to side or do you wind it/rotate it in place?
How do you agitate?
If you only rotate it, you might try adding an occasional "left-right wagging" motion to the Lab Box to break-up any laminar flow within the box itself.
I'll hazard a guess and say these negatives were on the outermost wind of the reel; do you remember?
Directional effects are not confined to bromide drag. If you have a strip of film running through an otherwise still tank of developer, the liquid can develop hot and weak zones of developer strength without agitation to displace or move them around depending on the density or lack of density being developed below. You see this a lot in early continuous development processors for motion pictures until they devised turbulation or impingement bars that sprayed developer directly on the surface of the emulsion, breaking up any zones of strong or weak developer in the solution.
Think of these as very broad "Mackie Lines"...
FYI I added to post #20. Sometimes it takes a while to compose an answer...
Noted. Thank you.
I could take photos of the negs on a light table should it be of more help.
I have only experienced vertical marks as shown in the examples.
I don't think it is possible to change the orientation of the film with this particular tank.
Yes, you got the orientation right. I have a 35mm Rodinax and 120 Load-All rotary tanks that are like yours. Make sure you use the proper rotation speed, which you should find out for yourself. Mind cycles are in the 45 to 55 rpm's a minute. Also, I use as much developer as I can for each roll.
FYI I added to post #20. Sometimes it takes a while to compose an answer...
How did you ascertain the actual rotation speed that you are using? The amount of developer I am using is well within the limits of the minimum. I checked that with Ilford many years ago. As you know the tanks only hold 200 and 150 ml respectively so some dilutions are not advisable.
I found my speed of rotation by trial and error. I had no instructions for any of my tanks when I got them. So, when I used the Load-All tank the first time I thought the "slower the better", but learned different. I'm not saying I had the common bromide drag, but I did seem to notice a slight variation in density in wide-open sky. I then starting speeding things up a bit while keeping a close eye out for effects in highlight range. When I hit in the 40 rpm range, I was happy enough. I never tried high-speed rotation, so I can't speak on that. I only would use the tanks when I traveled to my cottage and back. We've been full time at the cottage now for several years, so I haven't used them in all that time.
A lot of gear discussion, but no matter what kind of tank (or tray), these are development fundamentals of agitation, for me:
Always random in direction - directional patterns in uniform areas ( like your skies) usually indicate a linear direction to agitation. If I'm doing sheet film, open tray, shuffling through top to bottom, rotating the stack each time 90˚. For roll film, in cylindrical tanks (Nikkor, etc), agitation is always inversions, with axis twisted, to avoid patterns. Even then then, I can get edge surge, from the rebate area.
Your artifact, noticing the direction of overdevelopment (the negative image is useful, for me), makes perfect sense to me as bromide drag. Thin areas (shadows, like the trees) do not exhaust the developer. The heavier (sky) areas do, so if the film is moving in the down direction, relative to the trees, there will be relatively unused developer coming into the sky, where the developer is already more used, or exhausted, and will go for the more highly exposed silver halides in the sky. You see them more against the sky areas that are not adjacent to trees, where there is no unused developer entering.
For what it's worth, medium format film has always been most susceptible, to me - more open areas for this to happen in the larger (than 35mm) frame. With sheet film, open tray, the agitation is totally random.
Without wanting to veer of topic my rotation speed is similar. A little faster than a 33rpm long playing record
To my eye, it looks like silver has migrated and then reattached itself to other silver grains
Was going to say the same thing myself Andy, but thought folks might laugh at me. Nobody laughs at a guy that devours donuts, so you're safe. Ask the cops. Those trees in the shot have lost a lot of silver, and it's got to go somewhere if not in the fixer or rinse?
Chuckroast can you say why pre-soaking may cure the problem when the OP has never used this and has never suffered this problem before?
pentaxuser
If this is the case, what is the cause and how does one avoid it?
As I stated earlier, try "wagging" the tank in a side to side motion occasionally while cranking the film during development and see if that helps; break up the flow of the developer.
These tanks are a compromise for convenience; they are not ideal for ultimate quality processing.
As an aside (and don't give this too much weight), I have been reading Grant Haist's book on Monobaths and it speaks of silver re-depositing itself via physical development when a small amount of sodium thiosulfate is present in the developer. Any chance of a slight fixer contamination in the tank when you process that could cause the silver to redeposit itself on active developer sites?
Just wool gathering here; fun to speculate.
I will certainly try 'waggling' the tank a little just out of curiosity although I have never had the need to do so until now.
I have developed at least a hundred films in this tank and apart from the mackie/edge effects that one gets with the inversion method I have never seen any difference in quality. But yes, it certainly is convenient and until now, very easy to achieve repeatable results.
I always use distilled water with the developer and for the last rinse. The fixer and washes are with filtered water through a Patterson filter.
Each chemical has its dedicated beaker and the tank is always washed immediately after use.
So I don't think contamination is an issue although it is certainly fun to speculate.
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