Digital BW, The Print

Hi John,

The products produced for the pastel trade are considered "archival" and are
used to stabilize those fragile  surfaces. I don't recall the source at the
moment but I recall reading that museum conservators routinely coat pastels
with such sprays. My wife, a professional artist,  uses them a lot when she
is working with pastels.

Paul Roark has posted a number of experiments he has done with print coating
with a number of products and if my memory serves me correctly ran archival
tests as well.

I printed a pair of step wedges on a number of papers and sprayed one with
whatever I was testing and left the other dry. After a couple of weeks in
the New Mexico sun I found very little change in the densitometric readings,
particularly the paper white; so as far as that crude experiment goes it
doesn't seem yellowing due to the coating is liable to be a problem. The
downside to their use in my view is the fairly unpredictable darkening of
the black pigment. The dmax will increase but the darker grays do so as well
and it isn't completely linear. I got so that I could predict how a
particular print would act and then adjust in photoshop so that the sprayed
version looked pretty much as I wished it to but it is hit or miss to some
extent. I finally decided it wasn't worth the effort even though it did
protect the surface nicely. Now if I get a flaked off spot I return to the
ancient darkroom method of hand spotting - argghhhh....

Roger
  -----Original Message-----
  From: johngeyles [mailto:jge@...]
  Sent: Wednesday, July 02, 2003 12:36 PM
  To: DigitalBlackandWhiteThePrint@yahoogroups.com
  Subject: Re: [Digital BW] Lyson Print Guard or Krylon Kamar on Hahnemühle
WT?



  > I have used Krylon Workable Fixativ and Krylon UV Resistant Clear. I
  suspect
  > that any of the fixatives designed for pastels might do.

  So, does anyone know what all these various sprays and coatings
  that are proposed here will do to print longevity ?  Obviously
  they provide protection to the paper and inks themselves, but
  what about the longevity of the spray coating itself ?  Seems
  like yellowing and possible cracking could be a serious issue
  and reduce the effective life-time of the print well below what
  good pigment inks on an acid-free paper would otherwise allow.

  I realize that increasing longevity is probably not the main
  reason people apply coatings - rather it's to increase DMax,
  in the case of Hydrocote PUR on matte papers, or to reduce
  bronzing, in the case of the Kamar and Lyson products on RC
  papers.  But is it worth it, if longevity suffers ?

  Just a thought, John



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