\
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.TH "Ppmflash User Manual" 0 "26 January 2003" "netpbm documentation"

.UN lbAB
.SH NAME
ppmflash - brighten a picture to approach white

.UN lbAC
.SH SYNOPSIS
ppmflash 
\fIflashfactor\fP
[\fIppmfile\fP]

.UN lbAD
.SH DESCRIPTION
.PP
This program is part of
.BR "Netpbm" (1)\c
\&.
.PP
\fBppmflash\fP reads a PPM image as input.  It changes the color of
each pixel to bring it a specified amount closer to white.  It
generates a PPM image of the result.
.PP
\fIflashfactor\fP is a real number between 0 and 1, inclusive.
\fBppmflash\fP increases the intensity of each RGB component by the
fraction \fIflashfactor\fP of the difference between the current
value and full intensity.  So if a pixel contains 60% full red, 10%
full green, and no blue and you specify 0.5 (half), \fBppmflash\fP
increases the red to 80% (because it was 40% from full intensity, so
it adds half of 40% to the original 60%), the green to 55%, and the
blue to 50%.
.PP
If \fIflashfactor\fP is zero, the output is identical to the input.
If \fIflashfactor\fP is one, the output is all white.
.PP
\fBppmbrighten\fP does a more normal kind of brightening.
\fBpamfunc\fP does a very simple brightening.  Both
\fBppmbrighten\fP and \fBpamfunc\fP can reduce brightness as well.
.PP
\fBpnmgamma\fP is another way people do a similar brightening, though
it isn't really intended for that.

.UN lbAE
.SH SEE ALSO
.BR "ppmbrighten" (1)\c
\&
.BR "pamfunc" (1)\c
\&,
.BR "pnmgamma" (1)\c
\&,
.BR "ppm" (5)\c
\&,

.UN lbAF
.SH AUTHOR

Copyright (C) 1993 by Frank Neumann
.SH DOCUMENT SOURCE
This manual page was generated by the Netpbm tool 'makeman' from HTML
source.  The master documentation is at
.IP
.B http://netpbm.sourceforge.net/doc/ppmflash.html
.PP