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Fwd: Re: Metals in Printing Ink
- Subject: Fwd: Re: Metals in Printing Ink
- From: Listman <email@example.com>
- Date: Fri, 09 Aug 2002 07:35:15 -0500
- Delivered-To: firstname.lastname@example.org
- Delivered-To: email@example.com
- List-Name: p2tech
- Reply-To: Listman <firstname.lastname@example.org>
Date: Thu, 8 Aug 2002 10:47:08 -0400
To: Listman <email@example.com>
From: Warren Weaver <firstname.lastname@example.org>
Subject: Re: Metals in Printing Ink
I used to work in the printing industry so I believe the following
response to be an accurate one.
Lead chromate yellow was still the yellow pigment of choice in the early
'70s. By about 1975 or 76, it was phased out in favor of diarylide
yellow, an organic pigment with no metal components. That's what is used
to print comics and all other newspaper inserts today. The blue pigment
used to print comics and other lower cost, lower quality inserts is iron
based (iron blue or ferric blue)-was then and still is. The red pigment
is barium based-again no change. Its called barium lithol red. Black is,
of course carbon black, totally organic.
Color inserts today are printed with one of three processes-offset
lithography, flexography and rotogravure. Most-60+%-are printed offset.
Fewer, but still a significant minority-perhaps 30% + or - are printed
with gravure and a very small portion-perhaps 2 -3% being printed with
flexography and virtually all of them being Sunday comics (about 30% of
all comics are printed with flexography). The inserts printed with offset
use oil based inks. Those printed flexographically use water based inks.
Those printed with gravure use solvent based inks.
For products printed on the lower end of the quality spectrum, the same 4
pigments are used with all three printing processes (though the way the
pigment is prepared for making the inks is different for each). With some
of the higher end products (though not frequently used for newspaper
inserts because of the added cost), the yellow, red and black pigments
are the same, but the blue is different. Incidentally, newspapers use
inks with the same pigments as comics.
Higher quality printing such as magazines and a small minority of
newspaper inserts use the same red, black and yellow pigments, but a
higher "cleaner" grade. The blue pigment, however is
different...and significantly more expensive. It is copper based. Iron
blue can't be cleaned up enough to obtain the quality of printing on
coated paper that is desired for magazines. Instead, magazine inks are
made with a copper-based pigment. These inks are known as "copper
blue", "cyano blue" or just cyan.
All of these pigments are quite stable, though they break down when
reacted with strong acids, as in the case of a TCLP test. This has not
been an issue except for the cyan pigments since copper is released and
detected in a TCLP test. Thus a waste stream containing cyan pigment
might be considered hazardous if copper is present in significant
quantity (rarely the case). Lead chromate yellow was, of course an
EH&S issue in the '70s. The only one that's been an issue over the
last 25 years is cyan, and even then it was not a major
Hope this is helpful.
Forwarded on behalf of Rusty
Harris-Bishop. Please reply to email@example.com.
I have a question regarding the color inserts in
newspapers (I believe it's a flexographic process). Does anyone know if
they still use metal inks in printing
these? Does anyone know when they
were phased out if they were? I have looked on the
print-tech archives, and didnt' see it answered, and posted a question,
but it didn't seem to get a response.
Anyone have any suggestions?
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