Re: Digital negatives for gum printing

[Katharine Thayer <kthayer@pacifier.com>]

Hi Joe,
That was a lot to read and I'll need to peruse it more carefully later,
but just a couple of quick remarks, since I'm going to be gone for a few
days and no doubt everyone will be on to something else when I get back,
not to mention that I've been spending way too much time here lately and
need to get back to work. 

1. I feel the same as you do about the mechanical nature of the halftone
printing process vs continuous tone; they really do seem like different
printing processes to me; one photographic, the other more a branch of
commercial printing or something. You and I draw our lines differently
about what parts of desktop digital fit on which side of that equation,
and it seems kind of an odd exercise anyway, to try to determine what's
"good" digital (more like continuous tone) and what's "bad" digital
(oooh, boo, more like halftone) because it's all digital, after all, and
I guess I just don't even want to go there. 

2. I've seen the partial print and stepwedge you refer to; all it
convinced me of was that you had compressed the tonal range of the
negative to fit the tonal range of the gum; that was the test I was
referring to in my earlier post when I said that could be done without
quadtone. The print itself did not seem remarkable in its detail, tonal
separation, or other qualities, and could be produced using what you
consider lesser digital negative types, in my opinion. 

This is not to take away anything of the joy and satisfaction you have
in your new system, it's just to say I'm not seeing yet what all the
fuss is about. A kind soul has generously offered to make me a quadtone
negative from an image of mine so I can make a gum print from it and
draw my own conclusions; no doubt this will happen in due time. 
. 
Katharine 


 

Smieglitz@aol.com wrote:

> 
> 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.