Digital BW, The Print

Tim Atherton wrote:

> great stuff Clayton - very useful
> 
> i don't suppose you've had any traditional silver 
> gelatin prints (Fibre and RC?) testing alongside 
> all these have you?

I want to add my support to Clayton's fade testing.  All the informal 
testing does add to the general knowledge base even if controls and 
numbers are lacking.  Moreover, the non-accelerated, perfect tests 
simply do not exist and would take way too long even if all the 
variables could be eliminated.  We'll all be dead by the time there 
is enough data to be useful.  So, I wish those doing the more perfect 
tests the best of luck, but we need to move forward based on what is 
doable within our time frames.  Luckily, B&W is much simpler than 
color, and carbon has a very long history.

I have put silver gelatin test strips in with my fluorescent light 
fade tests.  They are rock solid, with barely measurable yellowing.  
Only the best pure carbon on non-brightened paper has a chance of 
being in the same league.  As a practical matter, the pure carbon 
(Eboni) and the silver print change so little in a "Wilhelm decade" 
that I simply don't worry much about that any more.  I don't have the 
time or patience to test to the point where fade is an issue.

In the real world, my old silver prints are showing some yellowing of 
the paper due to atmospheric pollution -- acids, I assume.  (At one 
point I found an RIT paper that also found the atmospheric issues 
were, in the real world, what was limiting silver printn lives.)  I 
also find in the old photo digital restorations I do that physical 
damage, including cracking of the emulsion surfaces is the worst 
problem.  

Resistance to airborne acids may be where our buffered inkjet papers 
will prove to be superior.  I also think the Art Care matte board may 
be a good investment. (The alpha cellulose versions are not that 
expensive at Michaels.)  

With respect to cracking, I, frankly, don't trust any of the plastic 
papers -- inkjet or silver, but I know Kodak and others will argue 
otherwise.  I just don't think one can expect a sandwich of 
substances with differential expansion factors to not show the 
effects of the internal stresses such will involve -- but we'll all 
be dead before that shows up.  

Sadly, as complex as some think fade testing is, accelerated "age" 
testing is much more complex and uncertain.  Some of the companies 
that even make the products in that area are basically just shoving 
things into an oven -- crude.  We basically have to rely on the 
history of similar papers and pigments/dyes (and gas attacks) to 
guess what will happen due to non-light aging factors.  So, the cyan 
that is do solid in visible light fade testing just happens to be 
weak with respect to other factors (and some UV).  Thus my solution 
for B&W -- simply get ALL the color out of the image and learn to 
control the best carbon possible.


Paul
www.PaulRoark.com