Netpbm Image Workbench

How to use Netpbm Image Workbench

Convert one bounded PBM, PGM or PPM image to PNG, or export a supported static raster as raw Netpbm. Read P1–P6 pixels, including packed monochrome rows and 16-bit big-endian samples. Select the actual input transfer function instead of guessing whether its creator used standard BT.709, an sRGB variant or linear values.

1. Provide local source image.
2. Choose the supported mode and run the tool. Review its assumptions and any reported errors.
3. Copy the result or download a separate output; reset to clear the current form.

Good to know

• 8 MiB per file, a 64 KiB Netpbm header, 2,000,000 pixels and 4,096 pixels per side. Dimensions and exact raw-raster byte counts are checked before pixel allocation. A local Worker has separate 10-second preparation and 2-second computation deadlines.
• One P1–P6 image only; PAM, multiple-image streams, trailing raw bytes and extra plain samples are refused. Raw formats use exactly one whitespace byte before raster data; extra header whitespace is not silently skipped as if it were not a pixel. Comments and ASCII whitespace are supported while reading tokens. Decimal tokens are limited to 10 digits.
• PGM/PPM Maxval is 1–65,535; 16-bit input is reduced to an 8-bit sRGB PNG preview after the explicitly selected transfer conversion. Standard Netpbm uses full-range BT.709 values, not video limited-range levels. PBM uses 1 for black and ignores unused row-fill bits.
• Raster export supports the same strict non-animated PNG/baseline JPEG/simple WebP subset as the QOI converter, with no SVG or progressive JPEG. Native orientation that changes declared dimensions is refused. Transparent samples are composited over white in linear sRGB.
• PPM/PGM output uses standard BT.709 encoding and 8-bit Maxval 255. PGM uses linear-light Rec.709 luminance weights; PBM uses a fixed linear luminance threshold of 0.5 without dithering. This is not lossless color-managed archival conversion.
• Inputs are processed on this device and are not automatically saved or uploaded.