[Michael]

Trevor - Your method has to be superior to mine on one major count; but I have a question for you.

Firstly, on inspecting my *dried* negatives, I notice small (but disastrous) marks from contact with the flow control vanes in the tank - or else from to strong a flow governed by those vanes. It's not quite clear which. That means to me that my mat is too thick overall, leaving too little room for the film to move. Back to square one.

Now, the question for you: your illustration shows a tank lid without those vanes. Has the lid been modified or did it never have them?

[Don't worry about my light leak business - it's a separate issue which I'm going to ask about in a separate thread].