Quote Originally Posted by Michael R 1974 View Post
Ming Rider - uneven development and/or streaking are often the result of insufficient or non-agitation. The reason is that as development proceeds, by-products of development accumulate. These by-product compounds come from both the developer and the film.
I also believe (without any chemical knowledge) that this could be the sources of the streaks due to higher concentrations locally.
But what is the process that's going on:
1) heavier elements are sinking down, thus causing extra development from the bottom up;
2) lighter elements float to the suface, thus causing extra development from the top down;
3) heavier elements are sinking down, thus reducing development from the bottom up;
4) lighter elements float to the suface, thus reducing development from the top down?

All four seem theoretically possible, at least to me.
What are the chemicals that cause the effect and are they heavier or lighter than water?
Also, do we know if the side with the light streak was on top or at the bottom in the tank?

So maybe in the next test making a mark in the film (cutting out a sprocket?) to mark the top side?
And maybe develop a second part of the film under the same conditions, but with some minor agitating, say three or four times, to see what the effect is?