Digital BW, The Print

--- In DigitalBlackandWhiteThePrint@y..., Robert Morrison 
<rmorrison@p...> wrote:
> On 9/7/01 11:52 AM, "Martin Wesley" <mwesley250@e...> 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.

Robert,

I have been looking for a good reason to add onto the house. Not 
quite what the wife had in mind though. 
> 
> > 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 taped all of mine down on cardboard and the ones that initially 
curled like EAM pretty much flattened back out as they dried. You 
probably used the 250 gsm Museo like I did. The 365 gsm would be a 
better choice for coating. I do agree that the heavier papers are the 
way to go if you plan to varnish.

The tape was a problem. I tried several kinds but they all pulled the 
top layer off the paper where they were attached at the corners.
 
>  
> > 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

You can get a drying rack with 30 flat shelves from Dick Blick for 
$109 and let the dogs have the couch back. 
> 
(snip)

> > 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.

Was the yellowing a noticeable tint or just the papers returning to a 
more natural white as the brighteners were exhausted?
> 
> > 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.

That is good to hear since any coating is going to complicate the 
whole archival question just by adding another unknown. I have signed 
up for a workshop at Stanford to spend a Saturday afternoon looking 
at and handling prints from their photography collection going back 
to the 1850's. I certainly plan to keep my eye out for any varnished 
prints and how they have faired.  
> 
(snip)

> > 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.

I think that this makes sense if the fading is a result of oxidation 
of the pigment particle surface. UV may not be as significant a 
player in this reaction (other than as a source of activation energy) 
in comparison to a good oxygen supply.

Some people have reported dark storage color shifts with Piezo that 
were decreased by using one of the aerosol sprays. Did you notice any 
difference between your coated and uncoated control samples in this 
regard?

> >> 
> >> 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.

It is also significant that the coated prints are starting from a 
higher Dmax and can afford to give some up while the uncoated prints 
need to hang on to all they can. In addition, the higher the Dmax, 
the less sensitive the eye is to the change. A shift up from 2.2 to 
2.1 is not nearly as noticeable or objectionable as a shift from 1.6 
to 1.5

Can you share any of the Dmax data with us? Having varnished some 
prints, I have seen that the effect is huge but I have no 
quantitative values.

> > 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.

You must have a good hand with a brush. Everyone who has tried this 
and reported on it, has complained about brush strokes and dust. I 
used a very pricey DaVinci varnish brush, and while that is the right 
choice, it didn't entirely solve the problem. The more I varnish, the 
better I get, but with the smooth papers like EAM and LPM there are 
generally some sign of brush strokes or unevenness. There seems to be 
a point where the paper has just enough texture to minimize the brush 
strokes but not so much it looks strange when coated.

> 
> > 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.

I have used the MIS VM ink set in an Epson 1280 to print on the 
Eclipse Satine and the results are some of the most pleasing I have 
seen so far. It is really an excellent match of paper and ink. I am a 
bit concerned about the long-term life of the brighteners in the 
paper though. I have an uncoated print cooking on the rear deck of my 
car to see how it holds up. Your results are reassuring.

I had terrible results on a 1270 with Epson color inks on the Satine 
and Velvet. The prints were very weak. If Brightcube fixes the paper 
for Piezo inks, I hope they don't alter its current excellent level 
of performance with the MIS inks. In working with the two inks, there 
are some papers where they print very differently from each other and 
other papers where they are quite similar.

Jerry Olson reported excellent results with the Satine and the MIS 
color inks by the way.

(snip)

> 
> 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).  

Well that is true for the aromatic polyurethanes but the new water 
based aliphatic are considered to be non-yellowing. Golden mentions 
polyurethanes as providing some of the toughest and impermeable 
membranes but because they are not removable, they do not recommend 
them for conservation considerations but do recommend them for art 
that will receive rough handling (and floors of course).
 
http://www.goldenpaints.com/varnapp.htm under Types of Varnish.

In any case, I think most of the modern polymer varnishes should out 
perform the old dammar and mastic types.

> 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.

I think you could say the same for most of the polymers.

> 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.

I agree, the ideal path is to go to a paint or varnish company, 
explain the application and have a coating custom designed with all 
the assistance of their R&D personnel and labs.

When do you expect to have your coating on the market? I look forward 
to giving it a try.

Martin  

> 
> Robert
> 
> 
> ----------------------
> Robert Morrison
> rmorrison@p...
> 
> 310-397-2704
> 
> 4131 Bledsoe Ave.
> Los Angeles, CA 90066