I'll measure the light output with my incident meter and keep it for reference. It's probably a handy chart to have around anyway...
I've given it some thought and now believe the
Originally Posted by David A. Goldfarb
above statement the more likely correct. Two other
non-related matters were considered in making my
One; point light sources and the inverse square law
came to mind. Two; years ago I went from a 75mm to
a 105 when working close to the base board. More room
to work but had thought my exposure times longer
without actually testing. Dan
Yes, although cyan filtration is irrelevant to most B&W paper, at least in theory, so you could do 25C/40Y/50M, 0C/40Y/50M, or 100C/40Y/50M and they'd all print the same. Remember, cyan is "minus red," and since most B&W papers are (nearly) insensitive to red, adjusting the cyan filtration will have no effect. Again, this is in theory. In practice, there might be a tiny effect, particularly if your cyan filter blocks any non-red light. I did some tests once and found no effect with Agfa MCP310RC paper and my enlarger, but it's an oddball Philips PCS130 with PCS150 controller, which uses separate red, green, and blue lights rather than a white light with cyan, magenta, and yellow filters.
Originally Posted by PVia