It turns out that pnmgamma -cieramp -ungamma file.pgm
fails with the error message I originally reported. But if you redirect the input: pnmgamma -cieramp -ungamma < file.pgm then the program works. Evidently the problem is in parsing the command line. -- A. T. Young -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]