Laser print damage to paper

Robyn Waymouth <robyn.waymouth [at] thewomens__org__au> writes

>I have just noticed in a correspondence file from 2000 that some of
>the pages, most probably printed by a laser printer, now have very
>distinct rust brown shadowing of the text on the back of the
>page--you could read it quite clearly (with a mirror).  Given that
>this file, and possibly many others with the same problem, are
>designated for permanent retention under our Public Records Act,
>this is potentially a serious problem. I'm unable at this stage to
>identify the printer or the paper, but it only occurs on some
>discrete items in the file.

I would like to ask permission to use your post in a short article I
will write in our newsletter.  I want to address the fact that laser
printers and inks have varied greatly over the years.  Both the
temperatures at which the inks are applied and their compositions
vary.

Of course, my interest in this technology originally had nothing to
do with the archival quality of the printed page.  My interest was
in the particulates, gases, and vapors that are emitted into the air
by laser printers and their toxicity.  The particulates are in
nanoparticle size which is likely to mean they are an even more
serious hazard than larger particles of the same substances.  Those
of concern to you are the particulates that stay on the paper.  They
include carbon, iron oxides, titanium dioxide, cyan dyes, and more.
Titanium dioxide is considered a lung carcinogen by our National
Institute for Occupational Safety and Health and more recently has
been listed by the International Agency for Research on Cancer (2B).
Carbon nanoparticles appear to be able to penetrate the lung tissues
(in the alveoli), enter the blood stream and serve as foci for clots
which can cause strokes and heart problems. And most of the other
nanoparticles have never even been studied for toxic effects.  The
lab rat for these tests can be seen in your mirror.

That paragraph above should give you a clue that the "rust brown
shading" is probably just as you observed---rust!  And the bleeding
of the iron oxide color is probably not just due to solubilizing,
but to migration of nanoparticles into the paper.

But this observation of yours is likely to be the first in a whole
series of conservation issues. From my perspective, the amounts of
the toxic substances encountered by conservators of archived laser
documents is likely to be either insignificant or easily
controllable.  But the issues of degradation of the images and
treatment are going to be extremely difficult to solve since the
colorants and binders in these inks are usually trade secrets. And
they changed over time.  Even if you knew the ingredients of the
dozens of products in a given year, you probably wouldn't know which
was used on a particular document.  And so on.

I think we will all long for the days when a key struck a black or
red inked ribbon at room temperature creating no airborne
particulates whatever.

Monona Rossol, M.S., M.F.A., Industrial Hygienist
President:  Arts, Crafts and Theater Safety, Inc.
Safety Officer: Local USA829, IATSE
181 Thompson St., #23
New York, NY 10012
212-777-0062


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                  Conservation DistList Instance 27:9
                  Distributed: Sunday, August 18, 2013
                        Message Id: cdl-27-9-002
                                  ***