Quote Originally Posted by polyglot View Post
I'll give the preflashing a shot... do you preflash white? filtered? Seems to me (totally guessing here) it might be useful to preflash magenta to get an upswept curve: high contrast will register immediately in the highlights but the lower contrast won't have any effect until perhaps VI.
I preflash with a grade 2. To be honest, I haven't tried any other grades, as I simply assumed using the "ideal" grade 2 would give the best results as it would effect both of the VC "layers". But your thinking may have some usage. Try it out with different grades and report the results here for all of us to learn something new if anything interesting comes out of it...

In terms of exposure time: as required for pre-flashing, I determine the maximum exposure that still leaves my paper white. On my Laborator L1200 with Ilford Multigrade 500H head, that means 0.4 seconds at F16 and enlarger head set at its highest position.