I am experiencing problems with inconsistent test strips (tests do not match the chosen time for the straight print, thereby rendering my tests almost useless). My equipment: Omega B-8 enlarger with an Aristo coldlight head (v54 lamp, I think! I purchased it from an individual who did not know himself and I can find no indication of which type lamp). Contrast tests performed with Kodak Polymax filter se; after the exposure time is decided upon (all strips with grade 2 filtration), I then test for contrast by exposing one strip at the chosen time for each whole grade number. All strips/straight prints are checked in white light after drydown. The coldlight head is a greenish blue light, more green than blue to me and was installed in 2002. I believe the v54 lamp is compatible with slot in filtration.
Sorry for length of this question, but as an example: Last night I tested for exposure at 3,6,9,12,15sec (I do not use times that may correspind to f/stops)---all at grade 2 at f/8. The best time was, oddly, 6 sec,. usually its in between. I then tested for contrast, hoping that the contrast strip for grade 2 at 6 sec would match the exposure test at grade 2 for 6 sec------not even close. In fact, I ran a test without a filter (for the hell of it!) for 6 sec. and it matched the grade 2 test for 6 sec----crazy! It is not fun when I can't rely on my tests. I've had my eye on a Durst M670 Variable Contrast Black and White Diffusion enlarger and am fixing to pull out my wallet if I can't get help.
Thanks for any responses.