SFD to PGM Converter

Export FontForge glyph renderings as grayscale PGM images

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Grayscale Precision

PGM captures antialiased glyph edges from your SFD with full gray-level detail — great for optical analysis and font rendering research.

Cloud Processing

Rendering happens entirely on Convertio servers. No FontForge or Netpbm tools needed on your local machine.

Secure Handling

Uploaded SFD files are deleted after rendering and PGM outputs are purged within 24 hours to protect your font designs.

How to convert SFD to PGM

1

Select files from Computer, Google Drive, Dropbox, URL or by dragging it on the page.

2

Choose pgm or any other format you need as a result (more than 200 formats supported)

3

Let the file convert and you can download your pgm file right afterwards

About formats

SFD (SplineFont Database) is the native source file format of FontForge, the free and open-source font editor originally created by George Williams in 2000 under the name PfaEdit. The format stores a complete font project — glyph outlines (cubic and quadratic splines), advance widths, side bearings, hinting instructions, kerning and OpenType feature tables, naming records, and metadata — in a single human-readable text file. Each glyph is described by its Unicode code point, outline coordinates, reference composites, and anchors, making the entire font design inspectable and diffable with standard text tools. SFD functions as the editable working format during font development, from which finished fonts are compiled to binary formats like OTF, TTF, or WOFF. A primary advantage is version control friendliness — because SFD is plain text, font designers can track changes to individual glyphs, merge contributions from collaborators, and maintain full revision history using Git or any other VCS. The format's completeness is another strength: it preserves every piece of data that FontForge can represent, including TrueType instructions, contextual substitution lookups, and multiple master axes, avoiding round-trip data loss during editing. The SFD specification is publicly documented and has evolved through several versions. FontForge's widespread adoption in the open-source type design community means SFD serves as the source format for hundreds of freely licensed font families distributed worldwide.
Developer: George Williams
Initial release: November 7, 2000
PGM (Portable Graymap) is the grayscale member of the Netpbm image format family, created by Jef Poskanzer in 1988 as part of the Pbmplus toolkit for Unix systems. PGM stores single-channel intensity images where each pixel holds a gray value from 0 (black) to a user-specified maximum (typically 255 for 8-bit or 65535 for 16-bit). The format exists in ASCII (magic number P2), where pixel values are written as decimal text numbers separated by whitespace, and binary (magic number P5), where values are stored as raw bytes. Both variants begin with a header specifying the magic number, width, height, and maximum gray value. PGM was designed as the grayscale intermediate in Netpbm's convert-process-convert pipeline philosophy: source images from any format are converted to PGM, processed using Netpbm's extensive command-line tool library, then converted to the target format. One advantage is format transparency — the ASCII variant makes image data directly readable by humans and trivially processable by text tools like awk and grep, invaluable for debugging and education. The scientific and computer vision community's adoption is another strength: PGM's straightforward single-channel representation makes it a natural format for image analysis algorithms, and many academic papers and course materials use PGM examples. The format is supported by ImageMagick, GIMP, and countless image processing libraries, and remains standard input for many research tools and benchmarks.
Developer: Jef Poskanzer
Initial release: 1988

Frequently Asked Questions

Why convert SFD to PGM?

PGM stores grayscale intensity values in a simple text or binary format. It is ideal for antialiased font glyph analysis in scientific or Unix environments.

How do I open a PGM file?

PGM opens in GIMP, IrfanView, and all Netpbm-compatible tools. Unix command-line utilities can parse the file directly for automated workflows.

Does PGM support antialiasing?

Yes, PGM supports multiple gray levels, so font glyphs can be rendered with smooth antialiased edges rather than jagged 1-bit outlines.

What is the difference between PBM and PGM?

PBM is monochrome (1-bit), while PGM is grayscale (typically 8-bit). PGM captures the smooth antialiasing of rendered font outlines.

Is this free to use?

Convertio converts SFD to PGM for free online — upload, convert, and download without any payment or sign-up.