Various Topics on Scanners

....

I need to set my scanner to be dead on.

DOes anyone know the dimensions of a sheet of A4 (European) in
millimetres accurate to 2 or 3 decimal places?

.... ..ecsol...am.sux.c..

In sci.physics Waxo <waxo@yahoo.co.uk> wrote:
> I need to set my scanner to be dead on.

> DOes anyone know the dimensions of a sheet of A4 (European) in
> millimetres accurate to 2 or 3 decimal places?

What makes you think the manufacturing tolerances are that tight from
sheet to sheet, or lot to lot, or manufacturer to manufacturer?

Or for that matter, when the humidity changes?

--
Jim Pennino

Remove .spam.sux to reply.

..dch..

Waxo wrote:
> I need to set my scanner to be dead on.
>
> DOes anyone know the dimensions of a sheet of A4 (European) in
> millimetres accurate to 2 or 3 decimal places?

A very informative site:
http://www.cl.cam.ac.uk/~mgk25/iso-paper.html

You can't set your scanner to repeatibly position paper to 0.01 mm, let
alone to the nearest *micrometer*.

Paper size varies with humidity (as well as the inherent imprecision of
production processes, as has been pointed out) so a single sheet of
paper will have different dimensions on different days.

As often happens on this forum, this is a request for an unrealistic
degree of precision. Are you trying to reposition your paper to within
a pixel? Take a LOT of time doing it by hand and use at least four
fixed microscopes with sufficient resolution.

Tom Davidson
Richmond, VA

..v..

Sometime on Tue, 30 May 2006 00:59:54 +0100, Waxo scribbled:

> I need to set my scanner to be dead on.
>
> DOes anyone know the dimensions of a sheet of A4 (European) in
> millimetres accurate to 2 or 3 decimal places?

210(+/-2)mm x 297(+/-2)mm is the best you will get.

http://www.cl.cam.ac.uk/~mgk25/iso-paper.html "The allowed tolerances are
±1.5 mm for dimensions up to 150 mm, ±2 mm for dimensions above 150 mm up
to 600 mm, and ±3 mm for dimensions above 600 mm. Some national
equivalents of ISO 216 specify tighter tolerances, for instance DIN 476
requires ±1 mm, ±1.5 mm, and ±2 mm respectively for the same ranges of
dimensions."

You can read the rest of that page for more than you ever wanted to know
about paper sizes ;-)

Also bear in mind that paper which has been through a heat based printing
process (eg photocopier, laser printer etc) will shrink to some extent.
Likewise, paper left in a particularly dry environment may shrink slightly.

--
Dave
Beauty is in the eye of the beerholder

.... ..n ..r ....

"Waxo" <waxo@yahoo.co.uk> wrote in message
news:Xns97D2F41FF1D3E628D1@127.0.0.1...
>I need to set my scanner to be dead on.
>
> DOes anyone know the dimensions of a sheet of A4 (European)
> in millimetres accurate to 2 or 3 decimal places?

In addition to the suggestions and link already provided by others,
you didn't explain the reason for, and your meaning of "to be dead
on".

If my reading between the lines leads to the correct ***umptions, you
may rather need a good method for registration of multiple images,
possibly with morphing capability.

In that case I'd suggest having a look at Panorama applications, since
they allow to achieve good registration *and* high quality resampling.
A free version of such an application can be found at:
http://hugin.sourceforge.net/

Bart