Digital BW, The Print

South window tests are good indicators on how an "unknown" paper/ink
combination will work, when compared to a "known combo". Putting
samples in the window without this kind of comparison will not yield
very valuable information. (even with a control sample stored in a
like situation but in the dark)  

A low humidity situation with dye inks, will tend to skew results in
making you think they are more fade resistant. I don't believe
humidity is nearly as important factor with pigmented inks as with dyes. 

Dye inkjet inks "co-mingle". The prefered papers are swellable
polymer, which tend to isolate the droplets, from one another. The
co-mingling of dyes, causes premature failure of the weaker dye.
Humidity plays a roll, the higher RH, will cause the dyes to migrate
even within the swellable polymer ink receptor, again causing
pre-mature failure. 

This complex situation regarding humidity levels is why the major
players have all gone to using pigmented inks for "archival" results.

John Nollendorfs 
--- In DigitalBlackandWhiteThePrint@yahoogroups.com,
"mccormick.mark59" <mark@...> wrote:
>
> --- In DigitalBlackandWhiteThePrint@yahoogroups.com, Ernst Dinkla
<edinkla@> wrote:
> > If I do 
> > not trust a paper that hasn't been tested somewhere else I 
> > hang half a print in a glass window facing east. That place 
> > is hardly heated and humidity is usually above 50%.
> 
> Artists' window tests where prints are taped to a window have a lot
of infrared (IR) energy 
> exposure that doesn't occur at locations further into the interior
of the building. I have 
> measured print surface temperatures as high as 54 degrees centigrade
(130 deg. F) under 
> those conditions so desiccation is still very strong even though the
print is indoors.
> 
> Best regards,
> 
> Mark
> http://www.aardenburg-imaging.com
>