Damage caused by Hand-held scanners

[Daniel Albano (1)]

On Thu, 26 Jun 1997 remelt at legacy.calvin.edu wrote:

> Greetings,
> 
> A professor here is traveling to Central America to scan (with a
> hand-held scanner)  manuscripts of a Honduran novelist. The
> archivist at the site is afraid the scanning will damage the
> manuscripts. However, the professor could accomplish a lot of work
> in a little time if he could scan. 
> 
> My question: Should the archivist be concerned? If not, does anyone
> know where we can locate a document (or documents) that  
> conclusively says scanning with a hand-held scanner is not harmful. 

	
	As has been said by others, it depends on the state of 
	the subject documents.  It is, of course, the function
	of the archivist to be concerned about this sort of
	thing, and if the document is in any sense fragile, I
	would hesitate to subject it to any common scanner, 
	whether hand-held or flatbed.

	The handling issues are significant, and any scanner
	will produce abrasion, and stresses due to flattening.

	I would suggest that the highest quality reproduction
	would by achieved with a 35mm camera, a suitable 
	lens, and a copy stand.  If the documents are black 	
	and white (or any two colours of contrasting reflectivity)
	your best choice is probably 35mm copy film - a high
	contrast black and white film that is intended for 
	exactly this purpose.  

	In the (less likely) case that the documents are coloured,
	consider a slow, fine grain colour film, either negative,
	or transparency (slide) film.  In that case, chose a low
	ASA/DIN around 100/21 or less.  

	If you can't get copy film, get a slow, fine grain black
	and white film around 32-50 ASA, and develop in an extra
	fine grain developer.  Ilford makes a very good developer
	for these purposes.  Both Kodak and Ilford make good slow
	black and white films.

	Using flash is probably a bad idea.  With the copy 
	stand you can use longer exposures if needed.

	If you really feel a need to get the material into a
	digital form, you can then digitize from the photographic
	record.

	Of course, you could go all out and find a 2x2 or 4x5 
	camera, but that would almost certainly be excessive
	- the quality of modern 35mm. films and lenses is
	exceedingly good.



--
Daniel Albano                           daniel at nypl.north-york.on.ca
Computer Services                       +1 416 395 5907

"Views expressed are those of the author and do not necessarily reflect
the position of the North York Public Library."