>Can someone explain this process of using rods to apply the coating?
>...
Here is an information sheet I send to people who ask about it:
Coating inkjet prints (11/26/02)
I have been experimenting with print coatings that raise the dMax to over
2.0 and make the fragile surface of the inkjet prints much tougher and more
durable. Frankly, the coated carbon-pigment prints I've been making have a
visibly higher dynamic range than my toned silver prints, and the coated
surface is so tough that the print can be displayed without glazing. Once
the glass is gone, the dynamic range of the print can really shine. I don't
expect conservative gallery owners to accept the idea very quickly, but
side-by-side with glazed B&W prints, the unglazed, coated inkjet prints will
speak for themselves.
Sprays cannot give the dMax increase that I am looking for. A thicker
coating is needed.
So far, I favor applying the coating with a #30 wire-wound ("Mayer") rod
(from Diversified Enterprises 800-833-4644) [no longer deals with
consumers - 7/03] for Epson Archival Matte ("EAM") and a #15 for Eclipse
Satine. Legion Photo Matte with a #15 rod is rather non-reflective, and
with the #30 rod gets a very good dmax and a surface that is close to an
air-dried silver print.
Diversified Enterprises is not set up to handle small accounts. So, the
latest thought is to have MIS take over retail distribution on the rods.
For 8x10" prints I've been using a 16" (12" of winding) 1/2 inch thick rod
that sells for $22 (but there is a $25 minimum). If one has just a 13"
printer, I'd recommend 15" of winding and 19" total rod length. The rod
coating is the only process I've tried that can do a perfect finish in one
coat.
For coating material, some on the Digital B&W Print forum like the Golden
water-based acrylics for the first coat. The Liquitex version -- readily
available -- at 3 parts Liquitex to 1 part water is also a good coating. In
fact, I favor something like the Liquitex because it has no UV inhibitors,
which often yellow the print too much.
I currently think polyurethane ("PUR") may be a better coating. It's
superior toughness and resistance to humidity and chemicals may have
significant advantages over the acrylics. The best practical answer I've
found is the water-based (easy, even if not at tough as the 2-solution,
solvent-based, industrial-strength ones), aliphatic (non-yellowing),
Hydrocote (800-229-4937) Polyshield Gloss [try the satine finish also] PUR.
This is available in one-quart size via mail/telephone order. The
wire-wound rods apply it easily with no dilution. It dries very quickly,
but takes about 7 days to cure completely.
The three papers that I've used that work the best are Eclipse Satine, LPM,
and EAM. They all can be coated with a single application. [Larger prints
may require thicker paper.]
To apply the coating with a rod, I tape the "top" 1/8 inch of the print to a
piece of 1/4" thick glass [thicker glass may be needed for larger prints]
using Scotch Removable tape. (Have the print upside down so that the larger
bottom border is the one taped.) The glass is for a smooth, flat surface
that I can razor off dried coating if necessary. I've been using a couple
sheets of copy paper under the print. For some papers it helps also to tape
down the bottom corners, although I usually don't bother with this.
About 7 cc (for an 8x10) of Polyshield pulled straight from the can with a
syringe fitted with an MIS bottom-fill attachment is used to lay a "bead" on
the tape and glass above the print. I make sure there are no bubbles in the
PUR not only before I lay down the bead but also after the bead is on the
tape & glass. After the bead is laid down, I pull some water into the
syringe and discharge it immediately a couple of times to stop the PUR from
setting-up in the nozzle.
Just before pulling the rod across the print, I use a blower to be sure
there is no dust on it. Since the can of PUR is only open long enough to
pull out what I need, there should not be any significant amount of dust in
the coating material (I hope -- so far, so good).
After the "bead" (or small, long pool) of coating is on the tape and glass
above the print, I pull the rod through the bead and down across the print.
The weight of the rod supplies most of the downward force needed. I don't
roll the rod, but rather drag it smoothly and not too slowly, keeping the
speed of the pull as constant as possible. If I get horizontal banding, it
is often because I've pulled the rod too slowly. After I've pulled the
excess coating away from the bottom of the print, I immediately rinse off
the rod. I definitely don't want the PUR to set-up on the rod. Having a
sink that is large enough to dump the rod into a water bath immediately
might be a good idea.
I quickly remove the tape from the print. If the PUR sets-up too much before
the tape is pulled off, it will pull off part of the print paper with it.
I usually put the 8x10 print on a dry paper towel as soon as possible. The
screw-driver that I used to open the can makes a handy tool to run under the
print edges to separate them from the paper and glass under the print.
A damp sponge soaks up the excess coating material and will clean the glass
easily.
Once the glass is clean and dry, I usually pull the print on its paper towel
back onto the glass and dry it a bit with a hair drier. By this time it is
also dry enough to just hang up to dry.
Between the tape, handling and other problems, I lose a little less than 1/4
inch of each print edge, but that still leaves a good 8x10 print area.
I'm still experimenting with this, so my materials and methods may change.
While the coating process is still experimental, I think it holds great
potential for taking our pigmented inkjet prints to a level that, in many
respects, exceeds the quality of the traditional silver print.
Paul
http://www.PaulRoark.com