RB to PNM Converter

Convert Rocket eBook to PNM anymap — free, online

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Universal Netpbm Format

Convert RB pages to PNM — the umbrella Netpbm format accepted by virtually all Unix image processing utilities.

Remote Execution

All conversion work runs on Convertio cloud servers. Your own device does nothing but upload and download.

File Security

Uploaded RB files are deleted immediately after processing. PNM output files are removed within 24 hours.

How to convert RB to PNM

1

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

2

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

3

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

About formats

RB is the native ebook format of the Rocket eBook, one of the first commercially available dedicated e-reading devices, developed by NuvoMedia and released in October 1998. Founded by Martin Eberhard and Marc Tarpenning — who later co-founded Tesla Motors — NuvoMedia designed the Rocket eBook as a handheld device with a reflective LCD screen, capable of storing approximately ten books in its internal memory. The RB format packages HTML-based content along with embedded images, metadata, and a table of contents into a single binary container optimized for the device's limited hardware. Content was purchased and downloaded through NuvoMedia's RocketLibrarian desktop software. A notable advantage of the format was its early support for bookmarking, annotation, dictionary lookups, and adjustable font sizing — features now standard on modern e-readers but revolutionary in the late 1990s. The Rocket eBook demonstrated viable commercial demand for dedicated reading devices, paving the way for subsequent platforms from Sony, Amazon, and others. NuvoMedia was acquired by Gemstar-TV Guide International in 2000, which discontinued the device line in 2003. While RB files are largely a historical curiosity today, they can be converted to modern formats using ebook management tools, and the format remains significant as a pioneering chapter in the evolution of digital reading.
Developer: NuvoMedia
Initial release: 1998
PNM (Portable Any Map) is an umbrella designation within the Netpbm family that encompasses all three classic portable map formats: PBM (Portable BitMap for monochrome), PGM (Portable GrayMap for grayscale), and PPM (Portable PixMap for color). Created by Jef Poskanzer in 1988 as part of the Pbmplus toolkit, PNM is not a distinct format with its own magic number but rather a collective name indicating that any of the three underlying formats may be used. When software reads a PNM file, it examines the magic number (P1/P4 for PBM, P2/P5 for PGM, P3/P6 for PPM) and processes accordingly; when software writes a PNM file, it selects the most appropriate subformat based on the image content. This convention allows Netpbm processing pipelines to pass images between tools without requiring the user to track which specific format is in use — every tool in the chain accepts PNM input and produces PNM output, with the actual format chosen automatically. The Netpbm toolkit provides hundreds of command-line utilities for image manipulation: scaling, rotation, color adjustment, compositing, format conversion, quantization, and analysis — all operating on PNM as the common interchange format. One advantage is pipeline composability: Netpbm tools can be chained with Unix pipes (e.g., pnmflip | pnmscale | ppmquant | ppmtogif) to build complex image processing operations from simple primitives, following the Unix philosophy of small, focused tools. The format family's cross-platform availability and language support is another strength — virtually every image processing library in every programming language can read and write PNM variants. PNM files are supported by ImageMagick, GIMP, and all major image tools.
Developer: Jef Poskanzer
Initial release: 1988

Frequently Asked Questions

Why convert RB to PNM?

RB is a dead format. PNM is the universal Netpbm format — accepted by virtually every Unix image processing tool and pipeline.

What programs read PNM?

GIMP, ImageMagick, IrfanView, all Netpbm utilities, and most Unix-based image tools handle PNM natively.

What does PNM contain?

PNM is a container that wraps PBM (mono), PGM (gray), or PPM (color) data — the format auto-selects based on content.

Is conversion fast?

Yes, PNM encoding is straightforward. Most RB to PNM jobs complete in just seconds on Convertio servers.

Is this free?

Yes, Convertio offers free RB to PNM conversion. Paid tiers provide batch processing and higher capacity.