Digital BW, The Print

On 9/7/01 11:52 AM, "Martin Wesley" <mwesley250@...> wrote:

Arrowed lines are from Martin Wesley...my responses follow.

> A mechanical question for you. Did you use a drying rack for the
> prints after you coated them? Finding a space to spread out 30 sheets
> would be an obstacle for most.

I left them flat. Drying racks would be ok for a final overnight cure, but I
would leave them flat while you are coating.

> How did you hold the paper down while
> you coated it or did you just manually hold it in place? Did you coat
> the entire sheet edge to edge or just the image area?

I tried a variety of things but found that simply laying the sheet on a
paper towel.  Taping edges made curling worse.  The key to good coating is
using heavy paper (300+ grams) however, some papers (e.g., XGS) do curl less
than others (e.g., Museo).
 
> I have found it desirable to leave the prints flat for a while after
> each coat to eliminate the chance of runs or sags in the event I
> missed any excess build up.

yes

> Did the prints fade evenly across the tonal range? Or did the high
> lights fade more quickly than mid-tones?

Too difficult to tell because of measurement error...but it appears that
they faded evenly.

> Did you observe any color shift in the inks or the paper base? Since
> the Eclipse Velvet and Orwell both appear to have brighteners (the
> Eclipse appears to have quite a bit) did you note any yellowing of
> the base? Was there any degradation in the brighteners' ability to
> fluoresce? Did it vary between the coated and uncoated prints?

Yes there was mild yellowing of the paper stock.  This was the same coated
vs. uncoated.

> What about yellowing of the coatings? I know that there is some
> initial yellowing of the prints by the coatings, some coatings more
> than others, did this stay constant during the fade test?
> 
None of my coatings yellowed.

> Did your coatings cover a range of different UV-inhibitors?

Yes the extent that manufacturer's reveal their ingredients

> Did some 
> inhibitors out perform others?

No, this leads me to believe that the inhibitor is not as important as
simply coating the pigment and sealing it from air.

>> 
>> 5.  There were not differences in fade between Orwell and Eclipse
> prints in
>> both the uncoated and coated conditions.
> 
> Can you quantify how much fade you did see?

5% reduction in 100% black Dmax coated, 10% reduction in 100% black Dmax
uncoated.  Remember that the actual effect is greater because these are log
scales.

> Heavier and a medium smooth texture. I found Museo to be the champ
> for taking a nice coating and not overly revealing brush strokes. I
> managed to coat some EAM but it was difficult. Have you tried coating
> any dry mounted prints?
> 
Interesting, in my tests, Museo was one of the most difficult papers to coat
because of curling.  I didn't have problems with brush strokes with any of
my coatings on any of the papers (good brush).  No experiments with dry
mounting.

> My attempts to print with Piezo on the Eclipse Satine and Velvet were
> very poor with extremely weak and veiled blacks. Coating some of
> these same prints utterly changed them from unacceptable to very
> good. The MIS inks seem to be much better suited to these papers.

Ditto. Photoinkjet.com is currently investigating improving blacks in these
papers for PiezoBW, but it is hard to say whether this will be good or bad
for coated prints.  Have you tried coating MIS prints on Eclipse?  I have
coated color prints from an Epson 10000 with jaw dropping results...so my
guess is that if the MIS inks are water resistant when printed they will
give great results as well.

> Oops. There's the answer to my drying rack questions. Any
> recommendations as to make, model and source?

Nope.  I simple lay them out and keep the dogs away from them.  My problem
was I was rushed when leaving for the UK and put them in an envelope to give
to Antonis the morning after they were coated...don't do this...its dumb.
> 
> I am concerned that Golden's approach of making an easily removed
> painting varnish is not applicable to coating paper prints, and may
> have properties that are undesirable for this application. Since it
> seems unlikely that the varnish could safely be removed from a paper
> print, taking a more permanent approach would suggest that the
> aliphatic polyurethanes would offer much greater strength and
> mechanical protection over the acrylics. I also found the Varathane
> Diamond product much easier and cheaper to work with.

Polyurethanes are notorious for having major fading problems...no one in the
industry would suggest using one for any application on a white substrate
(there even warnings on the cans).  Acrylics are much better from this
perspective.  Remember there are 100's of acrylics out there ranging from
low molecular weight solution polymers to very high molecular weight
emulsion polymers  with vastly different properties.  This complexity is one
reason that I decided to attempt to commercialize a product.  It simply was
taking too much time and money in development...although more power to you.

Robert


----------------------
Robert Morrison
rmorrison@...

310-397-2704

4131 Bledsoe Ave.
Los Angeles, CA 90066