Re: possible answer to archivalness comparison between carbon gum andpt/pd
Really good observations.
I am currently making a very thick carbon tissue (weight height of about 1mm) for negatives with a log density range of about 2.7. With the correct sensitizer
this tissue is capable of prints with great relief. I push the envelope on this since relief is one of the most distinctive characteristics of a carbon print.
At 4:53 PM -0500 3/1/08, etienne garbaux wrote:
Gawawin wrote:There are several reasons for this. One is, of course, that cracking occurs over time, particularly in prints that have been repeatedly cycled between high and low humidity, so it is most prevalent in old images. Newer images (i.e., most alt-process work) may not have been subject to cracking yet. Additionally, commercial carbon tissue from the 19th and early 20th centuries was typically made with thicker layers of gelatin with lower concentrations of pigment than is common among alt printers of the late 20th and 21st centuries, so for prints with equal D-Max the shadow areas are much thicker and more prone to cracking.The most amazing thing to me is that Sandy and others, who have no doubt seen far more carbon prints than I, have never seen cracking in the dmax areas. This has been so common in my experience that it often useful for identification. It doesn't always happen by any means, but I have seen more prints with cracks than I could count.