Contrast grades can vary significantly from manufacturer to manufacturer.
The paper we have had made in the last few years, Lodima, which is the sliver chloride replacement for Kodak's Azo, is currently in grades 2 and 3, both of which are softer than the grades of enlarging paper. We have just ordered a grade 4, which will be a little contrastier than an enlarging paper grade 3. There are ANSI standards for grades, but we have gone with what prints the best. Silver chloride papers are contact printing papers, with extremely long tonal scales and very rich blacks. We feel Lodima paper is the most beautiful paper available since the early 1940s. It has a slightly warm tone when developed in Amidol with the formula I devised. Here is a link: http://www.michaelandpaula.com/mp/newpaper.html
Michael A. Smith On 7/26/13 4:48 PM, BOB KISS wrote:
*DEAR MARK,** Fasten your seatbelt because, when Richard gets home from work, he will give you a thorough description of the methods used to determine paper contrasts for both graded and VC paper. ** However, in summary, although there are standards of how manufacturers are supposed to determine contrast of their papers, the reality is that, from manufacturer to manufacturer, there are significant variations of the contrast of both graded paper and VC papers for each "number" claimed by them. **As long ago as Adam's books, The Print and The Negative, he talked about the significant variations of contrast of #2 papers from manufacturer to manufacturer. Recall that his zone system was based on trying to produce a neg that print nearly perfectly on a "middle" contrast paper and he aimed his process at #2 contrast graded paper. **I pass the scepter to Richard...* * CHEERS!* *BOB* ** --------------------------------------------------*From:*pure-silver-bounce@xxxxxxxxxxxxx [mailto:pure-silver-bounce@xxxxxxxxxxxxx] *On Behalf Of *Sauerwald Mark*Sent:* Friday, July 26, 2013 2:09 PM *To:* pure-silver@xxxxxxxxxxxxx *Subject:* [pure-silver] Contrast gradesI understand how a higher number for the contrast of a paper, or for variable contrast papers, using a filter for the higher grade results in a higher contrast print. What I am wondering is if there is any objective measure of what a contrast grade of 'N' is. If I use contrast grade 3 paper from one manufacturer, will I see the same contrast as if I use grade 3 from another manufacturer?I imagine that plotting the exposure vs density you would be able to measure the slope of the curve at some point (perhaps when the density is at a predefined level,) and the steeper the slope, the greater the contrast - and you could define the contrast grades by defining this gradient for each grade has that been done? If so, where is it documented?Mark__________ Information from ESET Smart Security, version of virus signature database 8613 (20130726) __________The message was checked by ESET Smart Security. http://www.eset.com__________ Information from ESET Smart Security, version of virus signature database 8613 (20130726) __________The message was checked by ESET Smart Security. http://www.eset.com
