Computer output microform

Could any one out there provide me with information on computer
output microform and its quality in relation to the standards, now
well established in the US and the UK, for 35mm microfilm as a
preservation format.

I have a specific reason for asking this but it is not necessary to
waste space here giving the reason.

I share the commonly held view in the preservation field that 35mm
microfilm produced to preservation standards should be viewed as the
preservation format and the digital medium viewed as an access
medium. Both serve the information world, one ensuring the
preservation of intellectual content and the other improving access.
My question relates to a situation where both forms would be held
and a decision being made on whether to film first and then
digitise, or digitise first and produce the microform from the
digitised content using COM.  Will the output microform meet current
preservation standards in terms of resolution, density, reduction
ratios and processing requirements e.g., thiosulphate levels?
Resolution, density and reduction ratios become particularly
important in relation to 19 and 20 century newspaper filming and
this should be taken into account.

I have experience of microfilming and digital production but little
experience of COM and would find it very helpful to hear the views
of others.  In particular, institutional policy on COM as a
preservation format.

My question is basically, if a preservation microform and a digital
form are both to be held, does COM meet the preservation standards
we demand? Thank you in advance,

John McIntyre
Head of Preservation
National Library of Scotland
George IV Bridge
Edinburgh EH1 1EW
UK

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                  Conservation DistList Instance 12:60
                 Distributed: Friday, January 22, 1999
                       Message Id: cdl-12-60-010
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