wwp@yahoogroups.com:
Re: Java on PC/MAC (was Re: Origins of the Panorama view)
Francis Fougere 2005-Jan-20 19:59:00
Actually your correction is wrong. Displays don't really have a gamma they
have a tone response curve
which provide a measurement in gamma. The gamma of the working space and the
display have no relation. The Mac gamma of 1.8 dates back to gamma response
of the old LaserWriter on a 1 bit display.
Francis Fougere
----- Original Message -----
From: "Ken Turkowski" <#removed#>
To: <#removed#>
Sent: Thursday, January 20, 2005 2:26 PM
Subject: Re: Java on PC/MAC (was Re: Origins of the Panorama view)
>
> I'd like to correct this. Gamma for the Macintosh was chosen in order
> to provide a system gamma of 1.0 for the original 13" Apple RGB
> (Trinitron) monitor. It has nothing at all to do with the LaserWriter.
> I don't know where that rumor started.
>
> The system was defined as
>
> frame buffer -> lookup table -> digital-to-analog converter -> display
> -> eye -> brain
>
> and the monitor was the original 13" Apple RGB (Trinitron) monitor. It
> has nothing at all to do with the LaserWriter.
>
> The reason for this is to allow image generation in a linear color
> space. One of the places where this really makes a difference is in
> anti-aliasing computations. On my web page (in-progress!),
> http://www.worldserver.com/turk/computergraphics/gamma.html
> I show several zone plates which have been corrected for various
> display gammas. The zone plate with the minimum number of moires
> (phantom circles) is the one whose gamma is closest to that of your
> whole system.
>
> Many displays are set up so that the black level is set way below
> black, so that maybe the bottom 16 values all seem to be the same color
> of black. This setting seems to be preferred for text, and is why
> systems are initially calibrated this way. But it is not good for
> images, which sometimes have details that we'd like to see in the
> shadows.
>
> That said, even though I preferred a gamma of 1.0 for my 13" CRT
> monitor, nowadays I prefer a gamma of 1.6--1.8 on my LCD. I still find
> 2.2 to be too dark.
>
> -Ken Turkowski
>
> On Jan 20, 2005, at 4:35 AM, #removed# wrote:
>
> > From: "Francis Fougere" <#removed#>
> >
> > The following was copied from an other list server. For information
> > about
> > joining these lists or contact info please contact me at
> > #removed#
> >
> > it was explained to me that the Gamma of 1.8 for your Apple monitor was
> > first determined for an old Apple Laser Printer that no longer exists
> > today...
> > setting your monitor to a Gamma of 2.2 may more accurately represent
> > the
> > deep rich blacks that can be with todays modern desktop printers...
> > talk to you soon...
>
> --
> Ken Turkowski #removed#
> Engineer/Scientist http://www.worldserver.com/turk/
> Independent Consultant Industrial Grade Software
> Computer Graphics 2D 3D Immersive Imagery
> Photo-mosaicing Panoramas Computer Vision
> Applied Mathematics Numerical Analysis Optimization
>
>
>
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