[Tfug] Hand scanner recommendation?

[Bexley Hall]

> >> You can even use a camera for text and fine line drawings if
> >> it will let you store TIFF's or "RAW" format (I've seen
> >> photos of schematics stored as JPEGs that were little more
> >> than fuzzy clouds)
> > 
> > That reflects my experiences with using a digital camera (Canon
> > Powershot, model 240, IIRC; 2005 vintage) for close up work - can be
> > tricky and a bit time consuming to get a decent shot. Usually have to
> > use manual focus in macro mode.  Even then it's not particularly
> > straight-forward.
> 
> I wonder if one of the distinctions Don-Bexley was making
> is that JPEGS are compressed - bad for fine detail.

Exactly.  Line drawing have lots of very high frequency
components -- compared to "photos" (of people/places/things).
The DCT used in JPEG encoding acts like a low pass filter
(unless you set the "quality factor" very high -- which means
you end up losing the benefits of *that* type of compression).

> TIFFs or RAW - no compression good for fine detail, but
> they take up a LOT of space.

TIFFs actually *can* use compression.  But, *lossless* (vs the
lossy compression used in JPEGs).  However, you tend to end up with
bigger files... (of course, there are pathological cases that
defy each of the above assertions)

> > It seems puzzling that the market for hand image & text scanners has
> > dried up the way it has.  I remember seeing the magazines full of ads
> > for them back in the late '80's or so.
> 
> Not puzzling to me about hand scanners. They were crap.

That's calling a spade a spade!  :>

I think even the small "business card-style scanners" (i.e., a
slot into which you feed the image and it is drawn through with
rollers) suffer a bit from this (rollers end up developing a taper
unless *every* image scanned uses the full width of the roller)

> It was too difficult to steer them straight, especially
> with paper that had folds, etc... 

Imagine how hand scanners for The Blind are received... !
Hell, you can't even *see* if you have scanned "straight"!