Quote Originally Posted by Ed Sukach
The color differences between brands of enlarging lenses, and between different lenses of the same brand, would not surprise me much - but then after the years I've spent, it takes quite a bit to surprise me. I still don't understand a great deal - I'm just not surprised that there are things I don't understand.

It's interesting that you cycle the enlarging lamp a few times to "warm it up". I analyze the color characteristics of the lamp in my enlarger before every session, and randomly, during the session, and I've never found that the ambient temperature that exists in the optical system affects anything worth mentioning. What lamps - halogen, incandescent - or? are you using?

Between the three lenses I use - two Rodenstocks and one Schneider - I only see 3-4 cc difference. More would not surprise me, though (see above).
Variations in color balance of the negatives and paper, and chemistry - are more pronounced .. and analyzing for those would mask other variables.

I **LOVE** my ColorStar 3000 Analyzer. Without it I'd be lost.
The lamp is one of these here thingys - http://www.bhphotovideo.com/bnh/cont...=173239&is=REG

The main reason I cycle the lamp is due to another issue with this old dichro 45 computerized gizmo. If the lamp hasn't been operational for some time (haven't quantified 'some time' yet) then there exists a delay after hitting the timer switch before the lamp lights. I use the same Beseler time on two other condenser enlargers without any problem so I know it's this head. It's happened more than once where I would hit the switch (makes no difference whether I use the foot switch or the button) and stand for a few seconds dumbfounded in the dark before suddenly the lamp comes on. If I cycle it a few times just before getting the paper out I don't have that problem or the resulting under-exposed print.

These heads are quirky. I now understand why they went back to analog display for the filtration. The filter values being displayed by the LEDs fluctuate and are not consistent. It took me a few errors to find out that when I would turn the head back on after a period of time and the values were different than they were before -- leave it. The filtration remains the same, but not the display. There is no analog display to use either. So it is not possible with this head to return to a previous setting when re-visiting a negative with any degree of certainty.

The lenses then become one more variable, but at least they should be a consistent variable. I'm finding about 8 cc difference between my Rodenstock and Nikkor.

I have a working PM2 analyzer that gets me back to a skin tone ok, but that's all I've programed it for thus far.

Regarding the last sentence of your first paragraph... that's very Rumsfeldish.