Re: RE: Digital negatives for gum printing

[Smieglitz@aol.com]

In a message dated 08/03/2001 16:31:07, kgerling@ameritech.net wrote:

<<1) Black vs. color demonstrating color is better

2) Black or color vs. Quadtone demonstrating quadtone is better

3) Waxed/oiled paper vs. Pictorico demonstrating Pictorico is better

4) Any newer Epson printer vs. the "old beasts" of yesteryear, demonstrating

the newer stuff is better


Now THAT would be some handy information!


Keith>>

OK, I'll jump in here, with the disclaimer that gum printers always seem to 
be testing this or that combination of materials, etc.  I don't believe I've 
ever tried to do the same thing twice with a gum print.  As a result of this 
continuous tweaking, many of my attempts at gum prints have been abandoned 
halfway through as I went off in another direction, with another technique, 
or a previously untested pigment, etc.  So, I have numerous halfway-finished 
prints and a few gems that I treasure.

Along the way I have tried various types of negatives including in-camera 
exposures of the subject, enlarged litho positives/negatives, enlarged lithos 
using Liam's reversal process as well as Dave's LC developer, digital 
negatives from laser printers, inkjet negatives from older Epson printers 
(500, 600 1270 models) in both black and color inks, the Cone quadtone 
piezography inkset on an 1160 Epson, and just this past week, an oiled paper 
negative from the Epson 1160.

Any of these will produce a negative suitable for gum printing, but there are 
some differences.  An in-camera film is probably the best, unless you want to 
change something about the image.  Photoshop rules.

So, for the purist, shoot the film to be developed for gum printing and live 
with the results.

One can probably match the quality of an in camera film doing any of the 
enlarged negative routes chemically, but to get the perfect negative will 
involve testing, replenishing developers just so, and a greater expenditure 
in time in the darkroom.  Some of my favorite gumprints have been made using 
litho negatives.  In fact, I went back to using lithos for a while despite 
the ease of inkjet negatives from the older Epsons because the contone 
negatives simply look and print better to me.  The older Epsons print with a 
distinct dot and although they can produce a decent gumprint, real film is 
better IMO.

I came to this conclusion after many attempts at printing digital negatives 
using inkjet or laser negatives and discovering to my amazement that Stephen 
Livick used halftone negatives to achieve his magnificent technical results.  
I envision a halftone negative to be printing small columns (the dots) which 
are either on or off in terms of exposure.  (I believe Katherine and a few 
others have alluded to this exposure effect in some recent posts.)  Exposure 
is much simpler with the halftones- go, no go.  On the other hand, I see the 
contone negatives as printing miniature islands and peninsulas on the surface 
of the paper, with the shoreline getting eroded here and there as the soluble 
gum takes part of the insoluble gum away with it as it develops.  So h
alftones produce sharp columns, and contones produce landscapes.

As soon as I realized this, I pretty much abandoned halftone/inkjet 
negatives.  It suddenly seemed to produce a different type of print in my 
head.  I started seeing the prints as a bunch of microscopic, regular 
pattterns of gum columns, like little gum pins sticking up from the paper.  
Didn't seem right to me suddenly and Livick's technical expertise suddenly 
lost value as it became so mechanical in my eyes.  I want my prints to be 
more like Demachy than Livick.  It somehow seems more pure that way and thus 
better because I'm into the process as well as the result.  Getting there is 
half the fun (or more).

So what to do?  Revert.  ("We are Devo.")

And then suddenly along comes the Epson 1160 and Cone's piezography.  Another 
flip-flop for me.  There is absolutely no visible dot with this stuff.  It's 
in a different class.  And the curves (very simple BTW) make the stuff behave 
when making negatives.

Why is it so different?  Let me compare it to the older Epsons.  The older 
models produce a distinct visible dot on every transparency material I've 
tried (Epson, 3M, Pictorico, and several others).  The resolution of the 1160 
jumps somewhere into the neighborhood of 2600 dpi with the Cone system-there 
just isn't any dot to be seen and it is sooooo smooth.  The printer costs 
$250 and while the original inkset will cost a couple times that figure, it 
is certainly worth it for doing archival quadtone prints without even 
considering its functionality in making negatives for gum printing.  *The 
output of this printer is going to revolutionize vision.  The quadtone prints 
have a different aesthetic.*  A silverprint on crappy modern papers just 
doesn't compare to the quadtone prints, and this sentiment has been echoed by 
others-check out George Dewolff's editorial in the recent View Camera issue, 
or J.P. Caponigro's earlier article on the technology (in P.E.I. ? a few 
months ago).  In my opinion, you have to be using AZO or Centennial to get 
the same sort of feeling from a silverprint and these still are far different 
than the quadtones.  The quadtones are like Platinum mixed with french 
vanilla ice cream.

Printing negatives with the older models was a compromise.  Black ink only 
gives better maximum density, but the output resolution is limited.  At 
anything above 250 dpi or so, the ink begins to pool and puddle on the 
transparency surface and details become merged/blocked.  Lower resolutions 
(180, 200 dpi) work better with black ink, but then the column/pin thing 
starts up again in my head.  The laser printers fail for the same reason.  At 
anything above 300 dpi, more printer artifacts occur (on the lasers I've 
used)-negatives get banded, smooth tonal areas suddenly print with several 
minutely different tones, etc.  So we are back to lower resolutions and 
larger dots.

Using color inks with the older Epsons improved the smoothness of the 
negatives.  But one has to lie to these printers when using transparency 
materials in order for the "microweave" function to kick in at 1440 dpi.  You 
have to tell the printer the media is photo glossy film or paper to get the 
higher resolution effect.  The effect is smoother, but the pattern is still 
visible.  The color microweaved pattern still has a dotted appearence.  
Sometimes the ink begins to pool here as well.  And, though I never actually 
tested for this, I have a feeling the color inks did two other things: fade 
and affect the spectral response of the gum emulsion.  The tiny cyan, 
magenta, and yellow dots surely print at different speeds, so although the 
output looks smoother, I don't think it prints tonally the same as a black 
ink-only negative.  But, I never really bothered to attempt to match the two 
and test since the output is so different in its basic nature.

So, for smoothness, use color and higher resolutions.  For density, use black 
ink negatives and live with larger dots.  Both methods produce acceptable 
negatives for gum printing since the texture/resolution of the paper combined 
with the slight shrinkage of the substrate and slight operator 
misregistration all tend to mask the halftone pattern.  No need to change 
systems if you are getting results you are happy with.  I wasn't, until the 
1160 arrived.

As I understand the process, the Cone piezography software fills in the 
spaces between the dots in a print cell using dilute ink.  The Cone quadtone 
inkset/software is designed to fill in the gaps and cover the entire print 
cell so that no dot is visible.  Blank paper is covered by very dilute ink 
(comparable to a bit of silver fbf in terms of density effect) and the 
smoothness is unbelievable.  The Epson microweave pales by comparison-you can 
still see the dots and spaces.  In contrast, the Cone quadtone effectively 
emulates continuous tone, perhaps better than even a silver film with its 
inherent grain pattern.

With the piezography system and the proper Photoshop curve, you can fit the 
image scale into the scale of the gum emulsion.  No posterization, no 
multiple negatives for highlights vs. shadows, no visible halftone, etc.  
IMO, it makes for a better negative, simplifies the entire process, and 
produces a better gum print.

I've only printed a few gum prints using this system, but the results have 
been far and away much simpler and higher quality than what I achieved 
before.  I must also note that this change in printers was also accompanied 
by several other changes in materials.  I tossed out the UV tubes in favor of 
quartz-halogen, switched from ammonium dichromate to the potassium salt, and 
started using Pictorico transparency material.  The total system is much more 
predictable and consistent.  There is simply no comparison as far as I am 
concerned.  The new system is so much better.

I'm sure others will counter with ammonium dichromate is better, UV tubes are 
fine, older Epsons work, etc., etc., etc.  Fine.  If you are getting what you 
want, consistently, no need to change.  "If it ain't broke, don't fix it."  
But, in my opinion, the Epson 1160/Cone/Pictorico/metal halide/potassium 
combo is the way to go in terms of quality, consistency and predictability.  
It's not only "the next new thing", IMO it is THE thing.

I've posted a fragment of a gum print using this system on the Bostick and 
Sullivan webboard gum folder if you wish to see an example.  It shows a 
Stouffer wedge printed adjacent to a portion of the image using a single coat 
of gum emulsion.  Unfortunately, I can't show the entire image online as it 
is a personal nude, and I don't believe the model would feel comfortable 
having it displayed on the web.  But, enough of the image is there to see the 
effect of the printer, etc.  

Larry Rohrr (sp?) has also posted his first gum prints ever in the folder and 
I believe these were also done using the 1160 and Photoshop curve. So come 
by, check out the results, and join in the discussion.

Entry to the webboard can be found at:

http://sirius.secureforum.com:8080/~bostick/login

Joe

p.s., and BTW, apparently those Stouffer folks make a killer frozen lasagne 
as well as those step wedges.