Quote Originally Posted by Rick A View Post
MG filters will act somewhat as neutral density filters, but enlargment times that short smack of thin negatives. You will have to adjust your in camera exposures to account for this. Finding your personal ISO is necessary for quality prints. Read(or reread) the Negative and The Print by A.A.
Are you sure? I use a Zonemaster II to analyze my negatives and I've been developing them to print well with a 2.5 filter. I'm sure if I attempted a 5x7 with no filter on my Beseler 23C III it would be a mid to low single digit exposure. You can't change the density of the negative without changing the contrast.