Beefchicken Industries

LaserWriter Test Pages

These test page were extracted from LaserWriter ROM images. The IINT ROM images came from the MAME project. I extracted the first generation LaserWriter ROM images from a LaserWriter logic board I found on eBay.

I extracted these test pages from the ROM images in a fairly unsophisticated manner. I used a simple tool to interleave the four high byte and four low byte 64 kB ROM images into a single 512 kB image. I then loaded the image file up in a BBEdit and scrolled around until I spotted PostScript. This was copied into a new file, and tweaked until it successfully rendered.

In the PostScript files, there is section at the top where the printer name, switch settings and page counter are manually defined. This needs to be there because the logic that populates these fields is unavailable outside of a LaserWriter. The original LaserWriter has some interesting logic I haven't quite figured out yet, that tweaks the sample graphs subtly depending on the printer settings; some settings move the tick-marks on the line graph, others change the size and shade of the bar graph.

Note: The original LaserWriter test page is encoded as Mac OS Roman, and will not render correctly if the encoding is changed. In fact it probably won't render correctly on a non-Apple platform. As originally designed, It relies on the fact that the Apple logo exists as a standard character in Mac OS Roman encoding.

LaserWriter Test (300 DPI PNG)
LaserWriter IINT Test (300 DPI PNG)

LaserWriter ROMs

LaserWriter ROMs
LaserWriter IINT ROMs

And a very quick and dirty Go program to interleave the ROM images for further analysis: binmerge.go

LaserWriter Documentation

Accumulated documentation on the LaserWriter, the Canon LBP-CX engine on which it was based, and the original HP LaserJet, which used the same engine.

LBP-CX Series Service Manual.pdf
LBP-CX Series Video Interface Service Manual.pdf
LBP-CX, LBP-CXII Series Parts Manual.pdf
laserjet sm.pdf