Ken, thanks for the details on these. Would it be possible to drill a series of holes in the top plate to allow bubbles to escape? Seems like it should be feasible.
Originally Posted by Ken Nadvornick
Also, since the inner cage has a solid top over the loaded sheets (with a single large hole in the middle), it is possible to get trapped air bubbles underneath the top that show as irregular strips of lower density along whichever negative edge was facing up between agitations. Rapping the tank does not work in this case as the cage is not a spiral and there is no place for the bubbles to escape. One solution can be to add a few drops of Edwal LFN to the developer to reduce the formation of bubbles in the first place.
Given what the Nikor tanks cost, I wouldn't mess with it. Presuming you could find enough spots to drill without cutting anything, if the plate is weakened, then over time it could go out of alignment, and then you would really have problems. I could also see agitation problems emerging, and ultimately, the holes would have to be small and might not actually let bubbles escape, and could cause more bubbles.
I'm with David on this. One of the benefits of the Nikor tanks is their ruggedness. I wouldn't want to do anything to compromise that. And if you did purchase one, then later wanted to sell it, holes drilled into it by the previous owner might not be such a good selling point.
Regarding the issue of air bubbles, to be fair I've never read anywhere else about someone having that problem with this tank. Or if they did, they never wrote publicly about it. But I also know I have definitely seen it in my processing. Now I do compound all of my b&w solutions from bulk chemicals, so that may have something to do with it as well. Perhaps I'm leaving out some magical secret ingredient from the commercial equivilents.
Using the Edwal LFN seems to mitigate the problem for me, without affecting the development process. A much simpler solution than drilling, I think.
Beyond that, if one didn't mind a little leakage then laying the filled tank on its side with the top facing away from you and rolling it right-to-left at least one full revolution would give any trapped bubbles a clear path to spiral out from between the loaded sheets. Something like that may work, although I haven't tried it.
"Hate is an adolescent term used to stop discussion with people you disagree with. You can do better than that."
—'blanksy', December 13, 2013