Digital BW, The Print

Steve,

Pardon my delayed response to your post.  I'm just back from a spring trip
to D.C.  (The Remington night paintings in the East Wing of the National
Gallery are worth the trip.)

>... w/ Museum K (BO)on EEM, and
>another w/ Ultratones (VM 4.3) on Hannemuhle William Turner.

>Location was the
>BACK WALL of my Florida room. I emphasize that because at the back
>they get NO direct sunlight, just moderately strong ambient. Heat
>fluctuates between 80 and 95 deg.F. depending on wether the ac is
>on, and the humidity is probably never under 75%, so it's still a
>torture test.

>One month later: the Museum K shows a slight but noticeable magenta
>color shift that becomes very obvious when i lift the covered
>section to compare. Much more disturbing: the BORDER areas that have
>neither ink or base liquid on them have turned yellow. So much for
>EEM being enhanced.

The EEM yellowing doesn't surprise me.  I wonder if it is just the optical
brighteners burning out or if your relatively high humidity is causing the
acids to attack the paper quicker than usual.

I've never seen a magenta shift with these carbon black inks.  I'm
suspicious that the humidity and a paper reaction are part of what is going
on.  The higher the humidity (and temperature) the faster most of these
reactions will go.  This could especially be true with the acid reactions.
My reading suggests that the acidic H+ ion uses water molecules to transport
it to the cellulose and other things that it attacks.

>The VM 4.3 on Willie Turner OTOH shows no visible change. Not only
>did it it not fade or color shift, but I think (don't have a
>densitometer to verify) the exposed areas have actually GAINED a bit
>in DMAX. Paul Roark reported a similar result for the Epson matte K,
>does this mean the two inks are actually one and the same?

I've seen this increase in dmax with Eboni also.  I don't think the inks are
the same, however.  The Epson Matte Black is considerably warmer.  Also, the
Epson Matte Black is not a carbon ink, whereas MIS claims that Eboni is
carbon.

Paul
http://www.PaulRoark.com