AFF to JBG Converter

AFF to JBG online — free JBIG compression conversion

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Efficient Compression

AFF to JBG conversion uses JBIG encoding — superior compression for bi-level images, ideal for document storage and fax.

Server Processing

All conversion work runs on Convertio servers. Upload your file and let the cloud handle the rest.

Cross-Platform

Access the converter from any browser on any OS — Windows, Mac, Linux, or mobile devices.

How to convert AFF to JBG

1

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

2

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

3

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

About formats

AFF (Acorn Draw) is a vector graphics file format native to Acorn Computers' RISC OS operating system, introduced with the Draw application bundled in RISC OS 2 in April 1989. The Draw application shipped as a standard component of every RISC OS installation, providing users with a capable vector illustration tool at no additional cost. AFF files store vector objects as a sequence of tagged data blocks, each containing object type, bounding box, and type-specific data — supported objects include paths with straight lines and Bezier curves, text objects with font references, sprite (bitmap) objects, groups, and tagged objects for application-specific extensions. Path objects use cubic Bezier curves with move, line, and curve elements, supporting variable line widths, join styles, dash patterns, and flat color fills. The coordinate system uses RISC OS draw units at 1/180 inch resolution, providing precision for both screen display and print output. One advantage is the straightforward binary structure — the tagged block architecture makes AFF files simple to parse and generate programmatically. Native operating system integration is another strength: RISC OS renders Draw files natively in its desktop environment, treating vector graphics as first-class objects alongside bitmaps. While Acorn Computers ceased operations in the late 1990s, RISC OS continues under active open-source development, and AFF files remain supported through the platform's drawing applications and conversion utilities.
Developer: Acorn Computers
Initial release: 1989
JBG is a file extension for images compressed using the JBIG (Joint Bi-level Image experts Group) standard, formally ITU-T Recommendation T.82, completed in 1993 as a successor to the Group 3 and Group 4 fax compression standards. JBIG compression is designed for bi-level (black and white) images but can also handle grayscale and limited-color images by encoding each bit plane separately. The algorithm uses a form of arithmetic coding guided by an adaptive context model: for each pixel, the encoder examines a template of surrounding already-coded pixels to build a probability estimate, then feeds this estimate to a QM-coder (a variant of the Q-coder arithmetic coder) that produces a highly efficient binary output. JBIG achieves 20-40% better compression than Group 4 on typical document images, with the improvement being even larger on halftoned photographs and images with gradual density transitions where Group 4's simple run-length approach is less effective. The standard supports progressive encoding, where a low-resolution version of the image is transmitted first and progressively refined — useful for fax-like applications where the receiver can begin displaying the image before the full-resolution data arrives. One advantage is superior compression of documents containing halftone images: newspapers, magazines, and marketing materials that mix text with photographic halftones compress dramatically better with JBIG than with Group 3/4. The standard's ITU-T backing ensures it is implemented in document imaging hardware and software worldwide. JBG files are supported by ImageMagick and various document imaging tools.
Initial release: 1993

Frequently Asked Questions

Why convert AFF to JBG?

AFF needs the defunct Acorn Draw to view. JBG (JBIG) provides highly efficient compression for bi-level images — excellent for fax and document archival.

What opens JBG files?

JBIG-Kit tools, IrfanView, XnView, and document imaging systems that support JBIG compression handle JBG files.

Is JBIG efficient?

Very — JBIG compression is designed for bi-level (black and white) images and achieves better ratios than Group 3 or Group 4 fax compression.

Is the service free?

Yes — free with no registration required. Premium plans add batch support.

Is my data secure?

Fully secure. AFF uploads are deleted after conversion, and JBG results are purged within 24 hours.