Digital BW, The Print

On 9/23/02 1:31 AM, "Ernst Dinkla" <E.Dinkla@...> wrote:

> There's a general attitude in the printing industry that varnishes may be
> worse than the inks themselves.
> In the past the risk of varnishes getting yellow or brittle on hardening and
> UV exposure was something to count with. I'm using some of the best outdoor
> vinyl inks in silkscreen printing: Sericol's Polyplast E series.
> In the specs pages they advise to use them without an overprint varnish.
> Only where the surface may be subject to abrasion etc they advise to use a
> Polyplast varnish.

It is impossible to make general statements about varnishes yellowing.
There is a very large range of possible polymer technologies.  Some of them
yellow badly (e.g., polyurethanes) while others are quite good.  The
manufacturers of products frequently make decisions based on their potential
use which frequently require shot term display and the product needs to be
cheap.

Robert