1Ppmflash User Manual(0)                                Ppmflash User Manual(0)
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NAME

6       ppmflash - brighten a picture to approach white
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SYNOPSIS

10       ppmflash flashfactor [ppmfile]
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DESCRIPTION

14       This program is part of Netpbm(1).
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16       ppmflash  reads  a  PPM  image  as input.  It changes the color of each
17       pixel to bring it a specified amount closer to white.  It  generates  a
18       PPM image of the result.
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20       flashfactor  is  a  real  number  between 0 and 1, inclusive.  ppmflash
21       increases the intensity of each RGB component by the fraction flashfac‐
22       tor of the difference between the current value and full intensity.  So
23       if a pixel contains 60% full red, 10% full green, and no blue  and  you
24       specify  0.5  (half), ppmflash increases the red to 80% (because it was
25       40% from full intensity, so it adds half of 40% to the  original  60%),
26       the green to 55%, and the blue to 50%.
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28       If  flashfactor  is  zero,  the  output  is identical to the input.  If
29       flashfactor is one, the output is all white.
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31       pambrighten does a more normal kind of  brightening.   pamfunc  does  a
32       very  simple  brightening.   Both  pambrighten  and  pamfunc can reduce
33       brightness as well.
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35       pnmgamma is another way people do  a  similar  brightening,  though  it
36       isn't really intended for that.
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OPTIONS

40       There  are  no  command line options defined specifically for ppmflash,
41       but it recognizes the options common to all programs based on libnetpbm
42       (See
43        Common Options ⟨index.html#commonoptions⟩ .)
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SEE ALSO

47       pambrighten(1) pamfunc(1), pnmgamma(1), ppm(1),
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AUTHOR

51       Copyright (C) 1993 by Frank Neumann
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DOCUMENT SOURCE

54       This  manual  page was generated by the Netpbm tool 'makeman' from HTML
55       source.  The master documentation is at
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57              http://netpbm.sourceforge.net/doc/ppmflash.html
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59netpbm documentation            26 January 2003        Ppmflash User Manual(0)