Over the past few years, I've written a lot about the various members of the Mitsubishi CP-D70 family of printers, and how they were utterly worthless under Linux.

These printers are unusual in that they required the host computer to perform perform gamma correction and thermal compensation to the image data in order to generate sane output. (If this sounds familiar, it's because the Sinfonia CS2 was similarly afflicted). This relied on unknown, proprietary algorithms only implemented within Mitsubishi's drivers.

To make along story short, I've been attempting to reverse engineer those algorithms for nearly three years, and I'm pleased to announce that I've finally succeeded. While I can't promise the results are identical to Mitsubishi's own code, It is now possible to generate high-quality prints with these printers using entirely Free Software.

The library is called 'libMitsuD70ImageReProcess', released to the public under a GPLv3+ license.

Just to be absolutely clear, Mitsibushi is not responsible for this library in any way, and will not support you if you complain that the output is somehow deficient or your printer catches fire when you try to print pictures of Margaret Thatcher posing in her skivvies.

Here's the list of the now-functional printers:

• Mitsubishi CP-D70DW, CP-D707DW, CP-K60DW-S, CP-D80DW
• Kodak 305
• Fujifilm ASK-300

While all of these models are expected to work, only the Kodak 305 has actually been tested. Please drop me an email or comment here if you have one of these printers and would like to help test things out.

In particular, if there's someone out there with a dual-decker CP-D707DW, there are opportunities for further enhancements that I'd like to try.

All code except for the library is now committed into Gutenprint, but is not yet part of any [pre-]release. So if you want to test this stuff out, you'll need to grab the latest Gutenprint code and libMitsu70ImageReProces out of git and compile/install them manually. Once this is a little more stable I'll package the library code in a tarball for simpler distribution.

In other news, while the Kodak 305's official Windows drivers only expose 4x6 and 8x6 prints, the printer firmware also supports the 6x6, 4x62, and 2x62 sizes that the Mitsubishi CP-K60DW-S supports. You'll need to ensure you're using the 1.04 firmware! I have also received reports that the '305 will accept the K60's print media, so in theory 5x7 and 6x9 support is possible.

Happy printing!