Digital BW, The Print

On 29-03-14 15:47, Paul Roark wrote:
> Eddie,
>
> I use the non-UV version of Lascaux Fixativ.  The UV version is just like
> Print Shield and negatively affects the surface characteristics of the
> paper.  Mark (of aardenburg-imaging.com) believes the thickness of the UV
> coatings is so thin that the protective effect is mostly from the reduction
> of the rate of oxidation.  I agree.  Consistent with this view is the fade
> testing results of the black ink.  At partial load it's relatively weak.
>   At full load, it's strong.  With the very low viscosity Lascaux we're
> using acrylic to fill the coating instead of more ink.
>
> I have been using 4 coats, one each with vertical, horizontal, and 2
> diagonal patterns.  It is probably best to allow drying between each coat.
>   I sometimes use a hair drier to speed this drying, sometimes not.
>
> I'm in California and can spray all year in my open garage with cross-flow
> ventilation.  Wear goggles and don't breath.  I have a respirator that I
> use for very large prints.  Usually I just hold my breath during the
> spraying.
>
> The concept here is to lock up the absorbent material in the coating but
> not disturb the highly engineered surface.  Figuring out exactly how much
> Lascaux is needed to accomplish this is the problem.  I don't have an
> answer there.  (That is part of why I've switched the printer ink setup to
> increase the lightfastness, just in case the spraying was less than totally
> effective.)
>
> Search for deals on Lascaux.  Sometimes Jerry's will have a sale.  I buy
> quite a few cans when that happens.
>
> I have not done a lot of research on good and cheaper substitutes for
> Lascaux (non-UV).  I found it via a speech by a National Museum expert to
> the pastel painters' association.  It was one of the few 100% acrylic
> sprays he recommended.  The others seem to be gone -- some acquired by
> large paint companies that may or may not have changed the ingredients.
>   Lascaux has the original acrylic in it, which is non-yellowing.  Many if
> not most of the sprays will yellow.  I don't believe the ads on the cans
> after testing some "non-yellowing" sprays that yellowed in only 100 hours
> in my fader.
>
> Paul
> www.PaulRoark.com


Paul,

Check the Talens Protective Spray 680 too. It uses a white spirit 
cosolvent for the acrylic. Acrylic B-67 probably and not B-72 but I can 
not find the right description for it. The white spirit acts as a 
retardant so no build up on the velvet blacks of matte papers.
Your document referred to Shell Cyclo Sol 53 which became Cyclo Sol 100 
which became SHELLSOL A 100 in time. The last I know as an equivalent 
for white spirit in silkscreen printing so my guess is that Talens 680 
is related to that type of acrylic varnish mix described in the document 
you gave a link to.

I did spray different varnishes on silicon paper or polyethylene so i 
could remove the varnish layer to check its color and whether it 
hardened faster than the other ones. The Talens 680 showed good 
properties but it (the solvent) acts as a plasticizer on polyethylene 
(polyethylene swelled and kept that property) so for RC papers this is 
not a good varnish.
On a variety of matte papers it works well. The smell takes some time to 
disappear but I dislike it less than the amyl or ethyl odors of the 
other varnish types.

-- 
Met vriendelijke groet, Ernst

http://www.pigment-print.com/spectralplots/spectrumviz_1.htm
January 2014, 600+ inkjet media white spectral plots.