I am trying to calibrate my equipment for black and white landscape photography, I don’t have a densitometer to get the density of my negatives.

I´ve done a procedure I found in internet; I took pictures over of a coarse towel (with a good rough nape so to get detail in shadows) using a series of exposures to get the gray scale, and changing my developing time, being very careful with your time, temperature, and agitation,……

I get a developing time I think I´m near to my objective according to the prints I did, getting details in shadows and in high light .

I scanned the negatives and get for each one his media value from histogram from Corel Photo Paint which values vary from 0 to 256. I notice that grey (18%) is more or less 128 media histogram value,

MY QUESTION IS:

According to the media value I get for zone V (168.73) Do I need less time developing??? Maybe 30 seconds less.

Who calibrate my scanner and computer?????

-- MIGUEL DAVILA (mdavila@isolux.com.mx), October 14, 2002