Re: Gravure tissue (long)

Richard,

Craig (to whom you addressed your questions) would be better able to answer your
questions, but would like to put in my two cents. The particular color is not
really important, as long as it is not black. As the plate etches in the ferric
chloride the copper turns black, so the gelatine must be a color that makes the
process easy to see. It also helps to be able to read the image on the plate
after the laydown and development, so it has to be dark enough to stand out from
the copper background. Other than that, the color doesn't matter, but some shade
of red or brown seems to fit the requirements well.
   When you refer to the thickness of the tissue, I assume that you are referring
to the thickness of the gelatine layer? I will be interested in hearing Craig's
reply, but I would think that the thickness of the gelatine layer would make a
great deal of difference. As the gelatine blocks and transmits the ferric during
etching, a too thick layer would slow down the etch, particularly in the heavier
areas that correspond to the highlights of the image. By the time the highlight
were bitten, the shadows would be all blown out by undercutting the aquatint.
   Ideally, if all goes well, a properly etched plate should need little or no
retouching before printing. There is, in my experience, a bit of a difference of
opinion on this point. Artists, with a background in intaglio, find plate
reworking to be fine, and even look forward to the possibility of manipulating
the image on the plate. Others, who, like myself, approach photogravure as a
photographic process, find the need to rework the plate to be indicative of some
failure in the process.
  Finally, I am looking forward to what you come up with. On one hand, you will
have the ability to improve on the only gravure tissue available, but on the
other hand, I suspect that a lot of photogravurists out there have only used
Autotype, and if your new tissue varies too much in working characteristics (i.e.
exposure times, ferric concentrations, etc.), it may cause a deal of confusion. I
suppose some one like Craig could work out the differences, and write up a new
set of procedures, as all of the literature available today is based on Autotype.

Best Regards, Jack Reisland

Richard Sullivan wrote:

> Craig,
>
> I only took on class in gravure in the early 70's so I know what is
> involved but absolutely no expertise.
>
> Some questions.
>
> Do you prefer the burnt sienna color? Does the color matter at all?
>
> I am making the carbon with 250 Bloom gel which is pretty high. Would that
> be a benefit? You seem to say it is?
>
> Would a thicker tissue be of a benefit? Again that is implied in your
> comments?
>
> Haenfstengle was about 2.4 mil as I measured some once. Of course that was
> one sample. I can easily make 4 mil or better.
>
> Ashless gelatin was used in making tissue for ceramic processes so I am not
> sure why Autotype is using that. I could make ashless gelatin but it is a
> pain and would run the cost up.
>
> I assume that most plates need extensive retouch work before printing
>
> Thanks for your comments.
>
> --Dick
>
> At 07:14 AM 3/7/2004, you wrote:
> >Richard,
> >It's very exciting that you would consider making a carbon tissue for
> >gravure usage.
> >I don't think you would cut into Auto monopoly to the extent that they would
> >cease making their product, as it has a very healthy, if small, consumer
> >base in Europe.
> >
> >The problem that has been brought up about Autotype's tissue, referred to as
> >assh*les, is in my opinion, not a fault of Autotype's manufacturing, but
> >created during the actual process of making a gravure plate, or to a lesser
> >degree, during the sensitizing of the tissue. What people may be seeing
> >could be air bells trapped during the ferrotyping of the tissue. Not to be
> >confused with trapping air during laydown on the copper which results in
> >visual air tracks (bubbles) in the stencil. These actually don't etch, and
> >result in white spots on the final print.
> >But, trapping small amounts of air during ferrotyping create areas of
> >thinner gelatin, especially with Autotype tissue, due to it's low gelatin
> >bloom. These thinner areas will etch quicker and finally blow out to form a
> >"devil".
> >
> >The "star" like gunshot wounds to the plate viewed after etching were
> >commonly referred to as "devils" in the Rotogravure industry. They are
> >almost always prevalent in the shadow areas of the image because those are
> >etched the longest and this is where the tissue is thinnest. Also, they are
> >more of a problem when doing actual grain gravure due to the uneven surface
> >of the plate due to the aquatint resist.
> >
> >The main reasons they occur are due to:
> >1, dust contamination in the process of adhering the tissue to the plate
> >during laydown.
> >Even the best controlled environment will contain small dust motes which
> >will get between the tissue and plate during laydown, causing a microscopic
> >hole in the stencil that will start etching as soon as the plate is immersed
> >in ferric. This continues for the entire duration of etching resulting in a
> >creve-like hole.
> >
> >2. "free" acid contamination of the ferric chloride etching solutions.
> >This is probably a more prevalent problem facing people doing gravure work
> >today. The free acid will increase the rate of penetration by softening the
> >gelatin where it comes in contact, usually at the site of a dust mote, where
> >the gelatin is thinnest.
> >Hunt Blue label Roto Iron ferric chloride, still made for whatever exists of
> >the rotogravure industry today, contains a very small amount of "free" acid,
> >but it is negligible for most of our gravure applications.
> >If you are using a ferric chloride other then Roto Iron, you can be assured
> >it contains much to much free acid that must be neutralized with a solution
> >of ferris hydroxide.
> >
> >Both of these problems will at one time or another plague someone doing
> >gravures. I've had a close look at Autotype tissue before sensitizing and
> >have never seen any blowouts in the emulsion, though they may indeed exist.
> >But I believe the two points stated above are a far more common cause of
> >devils then holes in the tissue from the factory.
> >I base this on 30 years of using many different tissues and having these
> >problems intermittently with all of them.
> >MaGraw Colograph tissue was probably the best controlled and finest tissue
> >ever produced for photogravure. It went out of business in the mid 80's and
> >sold it's coating machines and proprietary formulas to the German Carbon
> >tissue makers Hansfstengle Gmbh. Hansftengle continued to manufacture the
> >duplicate MaGraw product into the early 90's, when it was forced to shut
> >it's doors. I purchased 19 rolls of carbon tissue from their last run, and I
> >can say that the last run they was not particularly consistent in quality!
> >But, at the time, it was still a better product then Autotype.
> >My main gripe with Autotype's tissue is the gelatin and pigment ( iron oxide
> >which is probably not as finely ground as one would like, as opposed to
> >MaGraw's burnt sienna). The gelatin itself continues to be dubious, a much
> >lower bloom then what was used in most pigment papers, hence the difference
> >in temperature (lower) and shorter time (to control swelling and absorption
> >of the dichromate) in the sensitizing process. It is slimy, course and not
> >workable above 53 degrees F besides being notoriously thin.
> >But, at the time being, it is the best pigment paper made for photogravure
> >by default!
> >Cheers, Craig Z.
> >
> >
> >----- Original Message -----
> >From: "Richard Sullivan" <richsul@earthlink.net>
> >To: <alt-photo-process-l@sask.usask.ca>
> >Sent: Saturday, March 06, 2004 2:37 PM
> >Subject: Re: News from Bostick & Sullivan
> >
> >
> > > Assuming this means gravure tissue, what is the gripe with what Autotype
> > > produces? Quality? Price? Would folks be willing to re calibrate to a
> > > different tissue. It is my understanding that Autotype dearly wants out of
> > > making it. The risk is if I come out with it and they drop it, I am in a
> > > pickle as I have then inherited the mantle. There would be no getting out.
> > >
> > > I have heard that some batches are plagued with what are in the trade
> > > termed assh*les, tiny areas that cause asterisk looking pits in the
> >copper.
> > > This i got from a couple of gravure printers here in Santa Fe and also in
> >a
> > > book on gravure from the 30's. I believe they are caused by small pinhole
> > > bubbles in the tissue. With this long a history it may just be an endemic
> > > problem in making the tissue.
> > >
> > > Thanks for the comments.
> > >
> > > --Dick
> > >
> > > At 12:07 PM 3/6/2004, you wrote:
> > > >I would like to recommend the production of gravure paper. Autotype could
> >sure
> > > >use some competition.
> > > >
> > > >Jack Reisland
> > > >
> > > >Richard Sullivan wrote:
> > > >
> > > > >
> > > > > With the coating machine I am looking at other coated products like
> >oil
> > > > > paper, collotype film, albumen, etc. Comments welcome.
> > >
> > >
> > >
Received on Sun Mar 7 13:42:37 2004