AW: Dot Gain
AW: Dot Gain
- Subject: AW: Dot Gain
- From: "Peter Baumbach" <email@hidden>
- Date: Thu, 1 May 2003 00:08:20 +0200
Roger and Ray,
Roger wrote:
>
Whereas optical dot gain refers to a
>
scattering of light around that very same dot image, it is an interaction
of
>
light and the dot color with the substrate. Light is reflected in all
>
directions around the dot shape. How far around into the substrate? That's
>
one type of problems that has kept scientists busy for a number of years
and
>
that is well understood scientifically nowadays, I suppose.
many thanks for clarification.
Roger wrote:
>
I am unable to visit your link but I know what the Herman grid illusion is
>
all about. It's a perceptual phenomenon where one sees gray squares that
>
don't exist between solid black rectangles separated by white gaps on a
>
grid. I don't think that phonemenon is at play here, in the context of dot
>
gain, because we're talking aabout ratios of density measurements, and, as
>
far as the instrument is concerned, there is no "perception" involved on
the
>
part of the densitometer.
I was on the wrong track because an illusion like the Herman grid only works
if many receptors of the retina are involved. In our case the size of the
single dots should be well below the resolution of the eye. Therefore, any
on-off contrast enhance mechanism of receptor fields would not work.
Ray wrote:
>
I am enclosing a quote from ANSI CGATS.4.1993 "Graphic technology--Graphic
>
arts reflection densitometry measurements--Terminology, equations, image
>
elements and procedures". This can be purchased from the NPES web site at
>
"http://www.npes.org";
many thanks for your help. It makes the optical phenomenon much clearer for
me.
Best regards,
Peter
email@hidden
www.pb-photo.net
_______________________________________________
colorsync-users mailing list | email@hidden
Help/Unsubscribe/Archives:
http://www.lists.apple.com/mailman/listinfo/colorsync-users
Do not post admin requests to the list. They will be ignored.