Paterson Tank 500ml of Chemistery as reccomended by Paterson.
I have even made a small plastic spacer for the centre column in the tank to make sure th Reel cannot slide up the column during Processing.
Agitation by Inversion method.
I've just checked - I assemlbed the reel and spindle and placed them into the Paterson tank without the "liner". 500 ml *will* cover - but there isn't a great deal of room to spare.
Interesting comment about a "plastic spacer". My Paterson reel is quite tight on the spindle - there is *very* little chance of its sliding.
I wonder - You DO have a Paterson "spindle".... smooth on the bottom, with no bumps to prevent the spindle from rotating, as are found on the JOBO spindles...? JOBO spindles are considerably smaller in diameter, and the reel would be free to slide up and down in inversion.
Other than that ... It must either be that 500ml is not quite enough, or that, in some way, the reel is chemically contaminated during development.
Or ... uh,... maybe burning some yarrow as a sacrifice to the gods of photography ... ?