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Pamtopnm User Manual(0)				       Pamtopnm	User Manual(0)

       pamtopnm	- convert PAM image to PBM, PGM, or PPM




       Minimum	unique abbreviation of option is acceptable.  You may use dou-
       ble hyphens instead of single hyphen to denote options.	 You  may  use
       white space in place of the equals sign to separate an option name from
       its value.

       This program is part of Netpbm(1).

       pamtopnm	reads a	PAM image as input and	produces  an  equivalent  PBM,
       PGM, or PPM (i.e. PNM) image, whichever is most appropriate, as output.

       pamtopnm	 assumes the PAM image represents the information required for
       a PBM, PGM,  or	PPM  image  if	its  tuple  type  is  "BLACKANDWHITE",
       "GRAYSCALE",  or	 "RGB"	and  its depth and maxval are appropriate.  If
       this is not the case, pamtopnm fails.

       However,	you can	override the tuple type	requirement with  the  -assume

       pamtopnm	 produces  a  PPM  image if the	input PAM has depth 3 or 4; it
       produces	PGM or PBM if the input	PAM has	depth 1	or 2.  Whether it pro-
       duced  PGM  or PBM depends upon the maxval: PBM for 1, PGM for anything
       higher.	The tuple type does not	play a role in determining the	output
       type.   You can use Netpbm programs such	as pgmtopgm to generate	a dif-
       ferent PNM output, but remember that Netpbm program  that  expects  PGM
       input will take PBM and so on.

       Note that it's possible for an image which is formally color to in fact
       contain only shades  of	gray  and  for	an  image  which  is  formally
       grayscale to contain only black and white.  This	program	pays no	atten-
       tion to that; an	RGB input image	produces a PPM output  image  even  if
       all  the	 pixels	 are  gray.  But you can use ppmtopgm to convert a PPM
       that you	know is	grayscale to the  equivalent  PGM,  and	 you  can  use
       pamthreshold  to	 convert  a PGM	image you know is black	and white to a
       black and white PAM image and then use pamtopnm to convert that to PBM.

       As with any Netpbm program that reads PAM images, pamtopnm  also	 reads
       PNM images as if	they were PAM.	In that	case, pamtopnm's functions re-
       duces to	simply copying the input to the	output.	 But this can be  use-
       ful  in a program that doesn't know whether its input is	PAM or PNM but
       needs to	feed it	to a program that only recognizes PNM.

	      When you specify -assume,	you tell pamtopnm that you  personally
	      vouch  for the fact that the tuples contain the same data	as be-
	      longs in the channels of a PBM, PGM, or  PPM  file.   The	 depth
	      must  still conform, though, so to truly force a conversion, you
	      may have to run the input	 through  pamchannel  first.   But  be
	      careful  with  -assume.  When you	-assume, you make an -ass of u
	      and me.

       pbmtopgm(1), pamditherbw(1), pgmtoppm(1), ppmtopgm(1), pamthreshold(1),
       pam(5), pnm(5), pbm(5), pgm(5), ppm(5)

       pamtopnm	 was  new,  along  with	 the PAM format, in Netpbm 9.7 (August

       This manual page	was generated by the Netpbm tool 'makeman'  from  HTML
       source.	The master documentation is at

netpbm documentation	       02 February 2018	       Pamtopnm	User Manual(0)


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