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List:       imagemagick-user
Subject:    Re: [magick-users] Level
From:       Anthony Thyssen <A.Thyssen () griffith ! edu ! au>
Date:       2009-05-22 3:47:27
Message-ID: 20090522134727.5a55107c () wraith
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On Thu, 21 May 2009 16:12:55 -0400
Steve Stachurski <sstachurski@lorsstudio.com> wrote:

| Hello-
| 
| I'm seeking some more information regarding the Level method that can be 
| performed to manipulate an image. I have tried dozens of different 
| ranges of black and white points, and I always get an image that is 
| either all white or all black. I have tried setting my black points 
| anywhere from 0 to 0.7 and my white points anywhere from 0.3 to 1.0.
| 
| I'm using PerlMagick to to this. There is a parameter to the Level 
| method, "levels," which takes a string, but I have no idea what kind of 
| string goes here.
| 
Two things.

You may be better asking in the IM Forums
   http://www.imagemagick.org/discourse-server/viewtopic.php?f=1

and secondly an example would be good.

Also have you first tried to use the command line -level operator
so you can understand what you are doing.

IM examples,  Color Modifications,  Direct Level Adjustments
   http://www.imagemagick.org/Usage/color/#level
Also look at the newer varients such as using +level (or adding a '!'
flag for Perl magick arguments)  and  -level-colors.

NOTE: using values like 0.3 and 1.0 probably produce black as it is
expecting values in the range from   0 to Quantumrange.  EG   65535
as such your values are all near zero and thus 'near black'.



  Anthony Thyssen ( System Programmer )    <A.Thyssen@griffith.edu.au>
 -----------------------------------------------------------------------------
    When someone tells me to go fly a kite I say 
                    "God bless you, thank you VERY much"
 -----------------------------------------------------------------------------
     Anthony's Home is his Castle     http://www.cit.gu.edu.au/~anthony/
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