Archived posting to the Leica Users Group, 2004/05/10

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Subject: [Leica] RGB2GRAY plug-in
From: bdcolen at earthlink.net (B. D. Colen)
Date: Mon May 10 11:01:36 2004

Sorry - IMG?

-----Original Message-----
From: lug-bounces+bdcolen=earthlink.net@leica-users.org
[mailto:lug-bounces+bdcolen=earthlink.net@leica-users.org] On Behalf Of
Douglas M. Sharp
Sent: Monday, May 10, 2004 1:53 PM
To: 'Leica Users Group'
Subject: [Leica] RGB2GRAY plug-in


Hi B.D.
the problem with the I-M-G is exactly what this plug-in is supposed to 
be correcting
.
I quote the readme file verbatim


Contents of the ZIP-File
------------------------

   The files included in this archive have been developed taking into 
account that conversions
from RGB to grayscale with a simple mode change in Photoshop are 
sometimes less controllable
than necessary. Therefore, we have created a plugin (PC only) and an 
action (a macro for
Photoshop 4.0 and later) that enable the user to take control of the 
weighting of the colour channels
in the final grayscale picture. The action is available in a German and 
an English version, because
of the different naming conventions of layers in these two versions.
   Both plugin and action do basically the same thing - choose the one 
that suits your personal style
best.
   To install the plugin, copy it into the plugins-subfolder of the main

Photoshop-folder.
Restart the application to select the plugin from the filters-menu. Add 
the action to your actions-
palette with the corresponding command from the palette (click the 
triangle in the upper right
corner of the actions-palette to open the menu).


RGB2GRAY.ATN
------------

   Action for PS4 (English version) to selectively convert RGB pictures 
to grayscale.
This action creates a picture containing four layers (the topmost being 
an adjustment layer
for gamma-correction).
   Arrangement and opacity of the layers simulate the brightness of 
colors as perceived by
the human eye. The green layer should not be modified - changing its 
opacity to a value lower
than 100% will make the transparent background (checkerboard) shine 
through, thus
brightening the image.
   If you want to optimize the picture using other than the default 
values, drag the opacity sliders
or change the gradation of the adjustment layer. If you prefer, flatten 
the file before saving it.


RGB2GRAY.8BF (PC only)
----------------------

   When the color sliders are set to 0, gray is composed of 30% red, 59%

green and 11% blue
(like luminance in Lab color space). Positive values on the color 
sliders enhance the part of the
selected color. Imagine this technique as putting a color filter in 
front of your camera lens -
the more intense the red filter, the darker blue sky colors appear and 
the lighter skin tones are
perceived. Choose a red value of 255, and 100% of the red channel will 
be copied to green and
blue channels.
   The contrast slider is still in beta - it is not a full-fledged gamma

corrector, but it does its job.
Brightness works as expected. Clipping operates just like the highlight-

and shadow eyedropper
in Photoshop's levels-dialogue.

   We know it's slow, has a small preview window and is constrained to 
physical memory - but as
it was done with Adobe's Filter factory, there is not much to be done 
about it. We hope it makes
your grayscale conversions a little more productive. Do not hesitate to 
email us under the following
addresses in case of improvements or praise ;). Please note that we 
cannot promise to provide
improved versions, though. The action and the plugin are freeware but 
copyrighted by us.

_________________________________________



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Replies: Reply from DouglasMSharp at netscape.net (Douglas M. Sharp) ([Leica] RGB2GRAY plug-in)
In reply to: Message from DouglasMSharp at netscape.net (Douglas M. Sharp) ([Leica] RGB2GRAY plug-in)