1\
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3.\" Do not hand-hack it!  If you have bug fixes or improvements, please find
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6.TH "Ppmflash User Manual" 0 "26 January 2003" "netpbm documentation"
7
8.UN lbAB
9.SH NAME
10ppmflash - brighten a picture to approach white
11
12.UN lbAC
13.SH SYNOPSIS
14ppmflash
15\fIflashfactor\fP
16[\fIppmfile\fP]
17
18.UN lbAD
19.SH DESCRIPTION
20.PP
21This program is part of
22.BR "Netpbm" (1)\c
23\&.
24.PP
25\fBppmflash\fP reads a PPM image as input.  It changes the color of
26each pixel to bring it a specified amount closer to white.  It
27generates a PPM image of the result.
28.PP
29\fIflashfactor\fP is a real number between 0 and 1, inclusive.
30\fBppmflash\fP increases the intensity of each RGB component by the
31fraction \fIflashfactor\fP of the difference between the current
32value and full intensity.  So if a pixel contains 60% full red, 10%
33full green, and no blue and you specify 0.5 (half), \fBppmflash\fP
34increases the red to 80% (because it was 40% from full intensity, so
35it adds half of 40% to the original 60%), the green to 55%, and the
36blue to 50%.
37.PP
38If \fIflashfactor\fP is zero, the output is identical to the input.
39If \fIflashfactor\fP is one, the output is all white.
40.PP
41\fBpambrighten\fP does a more normal kind of brightening.
42\fBpamfunc\fP does a very simple brightening.  Both
43\fBpambrighten\fP and \fBpamfunc\fP can reduce brightness as well.
44.PP
45\fBpnmgamma\fP is another way people do a similar brightening, though
46it isn't really intended for that.
47
48.UN lbAE
49.SH SEE ALSO
50.BR "pambrighten" (1)\c
51\&
52.BR "pamfunc" (1)\c
53\&,
54.BR "pnmgamma" (1)\c
55\&,
56.BR "ppm" (5)\c
57\&,
58
59.UN lbAF
60.SH AUTHOR
61
62Copyright (C) 1993 by Frank Neumann
63.SH DOCUMENT SOURCE
64This manual page was generated by the Netpbm tool 'makeman' from HTML
65source.  The master documentation is at
66.IP
67.B http://netpbm.sourceforge.net/doc/ppmflash.html
68.PP