ppmtolj

Convert a PPM file to an HP LaserJet PCL 5 Color file

$ ppmtolj [path/to/input.ppm] > [path/to/output.lj]

$ ppmtolj [[-g|-gamma]] [gamma] [path/to/input.ppm] > [path/to/output.lj]

$ ppmtolj [[-r|-resolution]] [75|100|150|300|600] [path/to/input.ppm] > [path/to/output.lj]

ppmtolj [-resolution resolution] [-compress method] [-nodither] [-gamma gamma_factor] [-magnify magnification_factor] [-xoff x_offset] [-yoff y_offset] [-landscape | -portrait] [-formfeed | -noformfeed] [-monochrome | -color] [-verbose] [-<number>] [-<number>x<number>] [ppmfile]

-resolution resolution
    Sets the output resolution in dots per inch (DPI), e.g., 75, 150, 300, 600. Can also be specified as WidthxHeight, e.g., 600x300. The default is typically 300 DPI.

-compress method
    Specifies the compression method for the PCL output. 0 for no compression, 1 for run-length compression, and 2 for TIFF compression (the default and usually most efficient).

-nodither
    Disables dithering. When converting a color PPM to a monochrome PCL output (or for printers that don't support many colors), this option will map colors directly without using dither patterns, potentially reducing image quality but also processing time.

-gamma gamma_factor
    Applies a gamma correction to the image. A value greater than 1.0 lightens the image, while a value less than 1.0 darkens it.

-magnify magnification_factor
    Scales the image by the specified factor. For example, -magnify 2 would double the image size.

-xoff x_offset
    Sets the horizontal offset of the image on the page in pixels from the left edge.

-yoff y_offset
    Sets the vertical offset of the image on the page in pixels from the top edge.

-landscape
    Sets the page orientation to landscape mode.

-portrait
    Sets the page orientation to portrait mode (the default).

-formfeed
    Adds a form feed character at the end of the PCL output, useful for ensuring a new page after printing.

-noformfeed
    Omits the form feed character at the end of the PCL output.

-monochrome
    Forces the output to be monochrome, even if the input PPM is color. This often implies dithering unless -nodither is also used.

-color
    Forces the output to be color. This option is only effective if the target printer supports color printing.

-verbose
    Prints informative messages about the conversion process to standard error.

-<number>
    A shorthand for -resolution <number>, e.g., -300 is equivalent to -resolution 300.

-<number>x<number>
    A shorthand for -resolution <number>x<number>, e.g., -600x300 is equivalent to -resolution 600x300.

ppmfile
    The path to the input PPM image file. If omitted, ppmtolj reads from standard input.

The ppmtolj command is a utility from the Netpbm package designed to convert a Portable Pixmap (PPM) image into a Printer Control Language (PCL) file suitable for HP LaserJet printers.

It reads the PPM image from standard input by default, or from a specified file, and outputs the PCL data to standard output. This tool is essential for users needing to print PPM images on LaserJet devices, as it handles various aspects of the conversion process, including dithering for monochrome output, image compression, resolution control, gamma correction, and page positioning. It allows fine-tuning of the output to match specific printer capabilities and desired print quality.

Generated PCL files can be very large, potentially exceeding printer memory limits for complex images or high resolutions.
Forcing monochrome output with -monochrome on a color printer might still result in color commands being sent if the printer's default behavior overrides the PCL instructions.

ppmtolj is part of the extensive Netpbm graphics toolkit, a collection of command-line utilities for manipulating graphic images. The Netpbm project originated in the early 1990s, with its roots in Pbmplus. This command, like many others in the suite, was developed to provide flexible and scriptable image conversion capabilities across various formats on Unix-like systems. Its design emphasizes interoperability and piping with other Netpbm tools.

ppm(5), pbmtoibm24(1), netpbm(1)