Digital BW, The Print

--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "andre1moreau" <andre1moreau@...> wrote:

> Thank you Mark for your clear explanations about print longevity.
> 
> To see how temperature and humidity may affect print life, the RIT Preservation Calculator may be of good use:
> 
> http://www.imagepermanenceinstitute.org/shtml_sub/dl_prescalc.asp
> 
> Andre
>

Yes, thank you for sharing that link. I'm well aware of the work and contributed some of my own research to these IPI image permanence models.  This is a good example where in certain circumstances one can combine some parametric terms (i.e. in this case temperature and humidity), but there are plenty of caveats. In this research, IPI was tracking temperature and humidity effects on chromogenic color dyes and cellulose acetate degradation, two significant thermal degradation processes in traditional film photography where the temperature effect be modeled very nicely by the arrhenius equation and where the relative humidity level contributes linearly to the reaction rate, so the humidity effect can be rolled into the overall rate calculation. Thus, this research by IPI and others is very nice information to have when looking at environmental storage conditions for traditional photographic prints and films.  However, humidity effects like the humidity-induced dye diffusion in inkjet prints don't fit that model, so they require different testing methodologies and different environmental models to evaluate correctly. I myself and other colleagues are actively engaged in these new research efforts, but it does feel overwhelming much of the time!

I started AaI&A with a mind to overhaul the light fade testing protocols for digital print media first because it was sorely needed, and because it was the most inexpensive testing protocol to get set up and running at my new company.  That said, if membership ranks grow, I will try to implement other new testing protocols as well...temperature, humidity, gas fading, physical properties testing, etc. All it takes is time and money!

thanks,

Mark
http://www.aardenburg-imaging.com