Digital BW, The Print

Folks, my point in making the initial post about the results on the 
Livick website was simply to point out to everyone that there are 
different ways to look at print permanence. I for one had mistakenly 
taken the Wilhelm years at face value and hadn't considered 
overcoating my prints to increase their expected lifetime. Why should 
I since the expected lifetimes reported by Wilhelm for ultrachrome 
inks were "long enough for me" already. What the Livick website 
suggested to me was that I need to rethink that position and take a 
more proactive approach. Both Livick and Wilhelm's data suggest that 
overcoating prints increases print lifetime. This could be partly due 
to UV filtering and partly due to the chemistry of particles that are 
suspended in a solid varnish where they are no longer at the air 
interface.

I am a scientist and I know full well how hard it is to get 
experiments right. The literature is full of data that was accepted 
for years and later proved to be wrong. We have tossed around a lot 
of general ideas on this forum like: glass filters the hard 
ultraviolet light. True but it doesn't filter all of the ultraviolet 
light. (They do make special ultraviolet filtering glass for artwork 
don't they?) How important is the unfiltered ultraviolet light on our 
inks? What is the quantum yield for photochemical reaction as a 
function of wavelength? Well we don't know for sure. So it's hard to 
definitively answer the question. 

The bottom line for me is not who is right and who is wrong. I just 
don't think we know for sure! I take this as a wakeup call which 
tells me that I need to be doing all I can to increase the longevity 
of my prints. Others on this forum have already done that but I have 
been lazy. Now I am much more concerned about using the right 
materials, paying more attention to overcoating prints, and doing my 
own testing.