Calibrating my dichroic enlarger using Paul Butzi's method - a few questions
I've just read and I think I understand most of Butzi's method of individually calibrating each paper stock to one dichroic enlarger head, but I have a few questions.
-Instead of buying an Em10 meter and never using it for anything else, can I just use my Sekonic L358 handheld meter to measure the light intensity change in the "Neutral Density Calibration" step? If so, would I use the incident or reflected attachment? If the incident, I assume it would be with the ball retracted as I am measuring a flat area?
-I had planned to get the Stouffer T3110 "3/4 x 8" 31 step wedge that Butzi uses and contact print it. But as long as I'm trying to save money, I do have a photograph I took awhile ago on 4x5 film of a Kodak Q14 greyscale (20 steps in 0.1 density increments between 0.10 "white" and 1.9 "black") Can I use this? 3 steps on the Stouffer wedge equals 1 stop, and the same goes for the Kodak. I just have to make sure that the steps remain about the same for each contact print through adjusting the lens aperture, and this should be just as easy on the Stouffer 31 step wedge as the Kodak wedge, as these both deal with 0.1 increments? But then what are the extra 11 steps on the Stouffer wedge? Just 11 more pure blacks? I did do a contrast assignment in college (it didn't deal with calibrating the dichro values to keep the same exposure) where I had to make prints from 0-5 contrast grade from this same Kodak Q14 reproduction negative and keep the 2nd whitest value the same for each grade. I remember reading these prints with the densitometer and that 2nd whitest white varied a little for each print even when I thought they looked the same. I won't have a densitometer to check this time.
-Paul Butzi mentions that you should use between 35-70cc's of filtration for each contact print, and I assumed you would choose one number (eg. 50cc difference in each step), but the differences in filtration for the original Magenta and Yellow aren't the same. Basically, his Calculated Exposure Scale numbers don't differ from each other equally. eg the lowest contrast is 21.00 the next is 18.5, the next is 14.75. Figuring out how he arrived at these numbers would help me, because I would like to think of these Calculated Exposure Scales as Contrast Grades, because saying Grade 2 makes more sense to me than saying Exposure Scale of 12.00. I understand that his Calc. Exposure Scale of 12.00 is probably equal to about 2 or 2.5 from what he wrote about it suiting most of his negatives, but how did he know that 12.00, not something like 12.75 or 13.00 was equal to 2 or 2.5?
Thanks and sorry if I sound a bit confused, I'm just trying to wrap my head around the whole idea before I actually do it.
Last edited by rjas; 08-03-2006 at 02:27 AM. Click to view previous post history.
If I were you, I'd send your questions directly to Paul. He's very quick in answering emails in my experience.
I did use his method quite a while ago, and I still use the charts I made from the data. It's helped my printing quite a bit.
Regarding your questions,
I'd give your Sekonic a try in incident mode without the dome. I didn't use an EM10 either.
Personally, I'd spend the few buck for the Stouffer scale. Wouldn't the film curve of whatever film you photographed with affect the spacing of the steps? If you could check it with a densitometer to verify the spacing, that'd be ok. If you want, I could read it for you.
Regarding grades, exposure scale is a more useful method for indicating paper grade than "grades", as the later very significanly from manufacturer to manufacturer. If you look in "Way Beyond Monochrome", and excellent book, it'll show you the ISO indication for various grades.