Digital BW, The Print

Varnishing Piezo (or Inkjet) Prints, Part 2

This was also posted on the Piezo List. The one thing to keep in mind 
in using this information to varnish over other ink sets is whether 
the inks are waterproof or not. Piezo inks are quite water resistant 
on matte papers and presented no problems. This may not be true of 
other inks, especially dye based or even Piezo on glossy papers. In 
these cases I believe these techniques are still valid if the print 
is first "fixed" with one or two light coats of a spray such as 
Krylon.

Okay here is my second installment in my narrative report on testing 
coatings for use on Piezo prints. Sorry for the time lag. Please make 
sure you are also keeping up with all the work that Mark Romine is 
doing on this as well. You will find it on the Piezo list
http://groups.yahoo.com/group/piezography3000
I believe he is much farther along with the Golden Varnishes 
especially the solvent-based MSA.

Trial 6

For this I one I wanted to use the sealer formula posted (#12841 on 
the Piezo list) by Peter (last name not given) but unfortunately I 
could not find one of the ingredients, Golden Medium GAC 700, 
locally. I have some on order and will give it a try when it comes in.

For this run I tried a sealer using:

1 part water containing 20% Golden Acrylic Flow Release (a surfactant 
or wetting agent)
2 parts Golden Acrylic Medium Gloss (substituting I part for the GAC 
700)

The varnish was:
1 part water containing Golden Acrylic Flow Release
2 parts Golden Polymer Varnish UVLS
(I mixed up two versions one using gloss and the other using satin)

I did the following coatings with about 60 minutes between coats:
1 sheet ConeTech Wells River and 1 sheet ConeTech Orwell with 2 coats 
of sealer and 3 coats of gloss varnish 
1 sheet ConeTech Orwell with 2 coats of sealer, 2 coats of gloss 
varnish, 1 coat of satin varnish
1 sheet of ConeTech Wells River with 2 coats of sealer, 2 coats of 
gloss varnish and 1 coat of satin varnish
1 sheet of EAM with 2 coats of sealer and 2 coats of gloss varnish

Results:

This sealer formula was a disaster. It resulted in a very uneven 
first coat and that first coat is the most important one. The Golden 
Acrylic Flow Release offers great improvement in the application of 
the varnish. It goes on much smoother with fewer bubbles and the 
brush strokes flatten out better.

The satin finish is rather nice. There is less Dmax gain but the 
overall result is not as startling on the textured papers as the 
glossier finishes. A mixture of gloss and satin might be very nice.

I personally like the coated Wells River better than the coated 
Orwell due to the smoother surface. 

Brush strokes are still visible with the Golden and there is 
variation in the sheen of the finish. I have pretty much decided that 
this is the nature of applying the coatings with a brush and I may 
not be able to completely eliminate them. You may or may not find 
this bad. The smoother the paper the more noticeable these issues 
are. 


Trial 7

This was done without a seal coat.

The varnish was:
1 part water
2 parts Varathane Diamond Wood Finish – Outdoor Semi-Gloss

This is the material I discussed at the end of Part 1. The aliphatic 
polyurethane that is non-yellowing. It is mentioned by Golden as 
being the strongest polymer but not suitable for paintings as it 
cannot be removed.

I did the following coatings:
1 sheet ConeTech Wells River and 1 sheet ConeTech Orwell with 4 coats 
of semi-gloss varnish 
1 sheet ConeTech Orwell with 3 coats of semi-gloss varnish
1 sheet Kodak Ultima Satin pre-sprayed with 2 light coats of Krylon 
clear, then coated with 2 coats of semi-gloss varnish

Results:

This looks really promising. With the 1:2 dilution it is definitely 
the easiest to apply with a brush of anything I have tried so far. It 
flows on very nicely with few bubbles and the brush strokes flatten 
quickly. It also dries very fast helping with the dust issue and 
shortening up the whole process. The finish is somewhere between the 
Golden satin and Golden gloss, still too glossy to my taste on the 
textured papers but close.

The finished surface was still a bit uneven due to the difficulty in 
getting a good first coat. It shows little to no brush strokes on the 
Wells River or Orwell. Once again any defects in that first coat tend 
to carry through all the following coats.

Brush strokes are noticeable on the Kodak but not as bad as the 
ClearSheild tried in Part 1. If a smooth finish could be obtained on 
this paper with the Varathane semi-gloss, you are getting close to a 
silver gelatin surface.

The Varathane claims to contain UV protection and is designed for use 
outdoors but keep in mind that it was designed for use on wood. If I 
had to pick a varnish right now I would go with this one but at some 
point fade tests need to be done to compare the different varnishes. 
Jon Cone's recommendation to add the Tinuvin-292 and Tinuvin-1130 
should be strongly considered, if the included UV protectors are 
unknown. See his posts #12330 and #12348 on the Piezo list.

Other developments:

Recently I returned to Home Depot to get some of the Satin Varathane 
to try.  I noticed that it is available in aerosol cans. So there is 
a water-based spray available. A couple of quick tests show that it 
does give some Dmax boost but not much. The finish is rather pebbled 
as if the droplet size is larger than the solvent-based sprays.

(It may be water based but it is not odor free. Much, much better 
than the solvent sprays but still too strong for use in the dinning 
room.)

This may have promise as a smooth undercoat prior to applying the 
liquid Varathane by brush. By itself I don't think it is very good.

There have been many posts on application method and I have a "puddle 
pusher" rod on order, which I will try when it arrives. Mark has 
ventured into airbrush and I refer you to those threads. It looks 
like the inexpensive ones do not have enough flow or flow adjustments 
to work.

Automotive spray guns were suggested and I checked them out at Home 
Depot. They have a promising one for ~$35 but you then need a 
compressed air or gas source to provide roughly 6 cfm at 45 psi. I 
looked at their small selection of compressor but it was not obvious 
if they would be sufficient or not. Price was at the $100 mark. Did 
see a portable air tank for $30 that you can fill at the gas station. 
Don't know if this would work or not. The spray gun looks rather big 
and might be overkill unless you have some large prints off a 7000. I 
will definitely consider one the next time I paint the house.

Silkscreen is an option and I may get to that eventually. It is 
inexpensive and easy but requires the use of larger amounts of 
varnish, which with things like the Golden, would be expensive for 
trials. The other draw back I see is that all the papers curve or 
buckle to some extent after the first coat. So a silkscreen 
application would be limited to one coat (unless the print was dry-
mounted first).  Also with a solvent based varnish you might get less 
buckling and be able to do multiple coats.

My next trials will include using Peter's seal formula. (The GAC 700 
came yesterday.) The Varathane Satin direct and the Varathane Satin 
over the Varathane spray. If the "puddle pusher" and/or the Semi-
Gloss ClearSheild (see Part 1) arrive, they will get a tryout too.

Thanks to everyone for all the suggestions and comments. Please keep 
them coming. If my course seems erratic it is because there are so 
many different things that could be tried. And don't forget to keep 
up with what Mark is doing and Peter if he posts again.

Martin