Re: [OT] Dot shape prevalence
Re: [OT] Dot shape prevalence
- Subject: Re: [OT] Dot shape prevalence
- From: Ernst Dinkla <email@hidden>
- Date: Mon, 10 Oct 2005 20:31:20 +0200
Graeme Gill wrote:
RS wrote:
Could you also build a screen with a custom dot shape like, say, a heart?
There was a paper in SIGGRAPH a few years back called "Artistic Screening"
by Victor Ostromoukhov and Roger D. Hersch in which the screens were
transitions
between arbitrary mini-images (such as Escher's famous Sky and Wood
woodcut).
See
<http://www.iro.umontreal.ca/~ostrom/publications/pdf/SIGGRAPH95_ArtisticScreening.pdf>
Graeme Gill.
There's a page with more work by Ostromoukhov on similar subjects
http://www.iro.umontreal.ca/~ostrom/publications/abstracts.html
For vinyl cutting plotters and vector design software I have
some BBC basic :-) programs written by a friend on my request
several years ago to make vector based screen patterns.
Building on that and in order to decrease filesize there was
also a near circular dot shape that had only two nodes on top
of one another. The next step was a trial to translate
greyscale images into vector based engraving patterns. The
goal was to get something like the digital facial engraving on
the Ostromoukhov page but resulting in vector based images. We
failed, it didn't look much like an engraving :-) The fun of
the vector shaped dots was that the shape could be changed
continually, not only in size but in form by changing the
vector angles etc. Slow though. It shouldn't be difficult to
make hearts and transform them to squares.
BTW, elliptical dots do suppress moiré in screen printing. It
may not be very effective in other printing processes but
combined with an extra 7 degree angle to the normal raster
angle set it helps in screen printing as it reduces the
effects of the double axis symmetry of the raster screens on
top of the double axis symmetry of the polyester fabric. It is
more difficult to avoid moiré on the Stork High Mesh (electro
formed metal screen) with its tripple symmetrical axis..
--
Ernst Dinkla
www.pigment-print.com
( unvollendet )
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