Re: [CinePaint] 12-bit PGM all images need manual adjustment (UNCLASSIFIED)

On Wed, 17 Dec 2008 09:44:45 -0500
"Levin, Don M CIV USA ATEC" <don.levin-SrL5qGCgbQJGMJYXDe/[email protected]> wrote:

> 
> Every PGM image looks dark, and requires doing View > Expose and
> adjusting Expose.  The images are 12-bit, and Cinepaint assumes 16-bit.
> Request you modify it to read the image depth, which is required by the
> PGM format, and adjust automatically.
>

Most image processing applications do not have provisions for
handling variable-bit-size images, such as 12-bit.  Only 8-bit and
16-bit are usually allowed and anything else is handled with
a floating point representation.

Your best bet would be to convert the 12-bit PGM to a standard
16-bit form before using cinepaint.  The NETPBM package (http://netpbm.sf.net)
is required for this and the command is as follows:

pamdepth 65535 old-12-bit.pgm > new-16-bit.pgm

This will only scale the values for the new bit depth.  The
luminosity of each pixel will be unchanged, but the image
will now be in a standard form and accessible to all applications.

GraphicsMagick or ImageMagick may also do this conversion, but
offhand I don't know the command syntax.

Frank Peters


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