26 Feb
2008
26 Feb
'08
7:40 a.m.
Grant,
On a side note, who here would be interested in ultra
high resolution
scans of old computer PCBs? I'm scanning all PCBs at 3200dpi for
archival. Photoshop won't save jpegs that large, but a 1600dpi scan is
only 50MB or so. Some day I plan to release my whole archive.
You mentioned JPEGs. If you are archiving the scans in JPEG format,
try zooming in on bunches of traces or text on the board. JPEG creates
a lot of artifacts.
It may very well be case that a 600dpi scan using lossless compression
will be much cleaner and usable than a 3200dpi scan using heavy JPEG
compression.
Even with 6 mil traces, 600dpi gives you more than 3 pixels per trace.
I've tried a few of my boards using 1200dpi, 8-bit color, and GIF/TIFF,
with results that seemed acceptable.
James Markevitch