Digital BW, The Print

----- Original Message -----
From: "Austin Franklin" <darkroom@...>
To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
Sent: Friday, September 20, 2002 10:32 AM
Subject: RE: [Digital BW] Photogravure and InkJet


> Hi Martin,
>
> > I also think that this is an excellent question. I will hazard a couple
of
> > guesses though. Gravure controls tone by varying the depth of the
> > etching of
> > the plate I believe or it can be a half tone process.
>
> BTW, when I say "halftone" here, I mean simply that it uses a single ink,
> and varies the tonality by laying more or less ink down with gaps between
> the ink the vary the graytone.

Well I think that it does it without any gaps or can be done with a
traditional line screen. I know someone in college (long ago) who was
directly scratching abstract designs into copper plates and etching them
with acid. The ink was applied to the plate with a putty knife and the
amount was proportional to the depth of the etching into the plate.

Check out:

http://www.lenswork.com/gravureprimer1.htm
>
> I'd like to understand just how the photogravure varies the tones.  I'm
not
> finding any really good information on that, but a close-up of the plate
> would probably help quite a bit...
>
> Here's one more explanation, a bit more detailed, but over my head:
>
> http://haleysteele.com/hs_root/learning/technical/index.html
>
> I'll have to read it a couple of times very slowly to get any
understanding
> of it.  Very bizarre picture as an example of PG by the way.

Thanks for the link. Very interesting although his explainations and
constant referrences to other printing methods I don't understand make it a
bit difficult. I do get from it that the ink density in the print is
controled by the depth of the acid etching.

Martin