DEC scanned documents for Bitsavers (message for Al Kossow)

Mouse mouse at Rodents-Montreal.ORG
Fri Apr 24 10:23:38 CDT 2015

>>>> The problem comes in overdoing the DPI.  Even 90 dpi is good
>>>> enough.  150, more that sufficient.  300 or 600, total waste, but
>>>> they are (obviously) the most accurate renderings.
>>> I would not call 90 dpi ?good enough?.  [...]
>> Why don't you actually try it.

I have tried it (I have a scanner capable of resolutions up to 300dpi)
and I agree: 90 dpi may be "good enough" for good-quality printing in
good shape with a large font and humans reading it.  If the printing is
dodgy, if the original isn't in the best of shape (dirty, creased,
etc), if the print is small, if it's something other than humans trying
to read it - each of those is reason to want better resolution.

Storage is cheap.  Especially, storage is _very_ cheap compared to
discovering after the fact that you don't have as good a scan as you
turn out to want of a document that's pretty; much unobtainable.

300dpi versus 90dpi is a factor of only a little over 11 in file size.
If that bothers you, send me the high-res scans and I'll keep them
safe; I'm willing to spring for a terabyte or two of disk if necessary
for the sake of keeping such things around.

>> Also, I'm assuming reading on a screen (where I read most of my
>> vintage manuals) vs. re-printing.

That's fine for your use, perhaps.  Not everyone does that.

>> My screen resolution is 90dpi.  Anything over that is pure waste.
>> Maybe you have better eyes than I do, but I can't discern image
>> quality over 100-200dpi for printing.

I can tell the difference between a two-pixel-thick line and a
three-pixel-thick line on a 300dpi printer.  Or, let me be precise, I
could the last time I tried; admittedly, that was a while ago, but I've
not had reason to think my visual acuity has got any worse since then.

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