ection they specify is CIE Rec. 709.

<P>However, people sometimes work with approximations of PPM and PGM
where the relationship between the image intensities and the sample
values are something else.  For example, the sample value might be
directly proportional to the intensity with no gamma correction (often
called &quot;linear intensity&quot;).  Or a different gamma transfer
function may be used.

<P><B>pnmgamma</B> allows you to manipulate the transfer function,
thus working with and/or creating pseudo