TTL CPU Re: IMSAI style C&K 7101 switches

Grant Stockly grant at stockly.com
Wed Feb 27 12:48:10 CST 2008


At 06:40 AM 2/26/2008, you wrote:
>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.

I scan all of my boards at 3200dpi 48bit color in TIFF format.  I'm 
not going to upload any 3.5GB images (one for each side of an S-100 
card).  If you mail me a hard drive I will be happy to copy them.  : 
)  Its faster to rescan them at 1600dpi 24bit than it is to open and 
resave them.

Color scans are needed if you want to have a PCB shop make gerbers 
out of your scan.

Grant 




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