Re: electronic/paper format & weeding

["Carla J. Montori" <cmontori@xxxxxxxxx>]

	The University of Michigan Library is involved in a 
number of  digital projects. Among these projects, those that focus 
on the conversion of brittle originals for the purpose of mounting 
the resultant electronic version on a Library website are managed 
in the Reformatting and Replacement Services (RRS) of the 
Preservation Division.  The Division has the resources in place to 
offer conversion to digital format as one of the suite of options in 
its use-driven brittle books reformatting/replacement program.

We consider all digital images captured, processed and 
stored to our specifications - done either in-house or outsourced to 
a vendor - to be archival.  All scanning is done at 600 dpi; images 
are stored as ITU Group 4  TIFF images (the ISO standard 
formerly known as CCITT Group 4 TIFF).  Once quality control is 
completed, no post-capture manipulation is done on the images, 
making the online TIFFs a faithful representation of the printed 
original.  The quality of the image seen by the user using current 
web-browsers is an artifact of our web implementation, where our 
software that does an on-the-fly TIFF to GIF conversion to enable 
the broadest possible viewing audience. The TIFF image stored by 
this Library is not altered.  As the technology matures, it will be 
possible to deliver higher quality derivatives that more closely 
mirror the TIFF archival images resident on this Library's server.  
The platform-independent online images are stored on a RAID 
system which has a high degree of reliability; our backup images 
are on digital linear tape (DLT) which would be used to restore the 
files on RAID if necessary. The Library and the University are 
committed to providing enduring access to these images,  with 
funding to support system maintenance and staff.  The TIFF 
images will be migrated forward to new storage and access systems 
as necessary.  

Intellectual access is further enhanced by OCR, resulting in 
a searchable text.  While the electronic text derived from OCR is 
subject to error, that error rate is low enough to permit a detailed 
level of intellectual access.  Further, as resources permit, we plan 
to edit the OCRed text to more faithful conformance to more the 
original.   The Library's confidence in the archival quality of the 
digital images it creates, together with its and the University's 
commitment to enduring access, make withdrawing the original an 
acceptable alternative. 

	The decision to withdraw an original rests with the 
individual selector.  The level of comfort with making withdrawal 
decisions - no matter what the format of the replacement - varies 
significantly.  Analysis of 15 years of disposition decisions 
indicates that something less than 40% of brittle originals are 
withdrawn after reformatting into or replacement by a stable 
format copy.  I do not for a moment believe that there will be a 
sudden rash of withdrawals of originals after conversion to digital 
format.  However, I do believe that selectors will make the 
decision to withdraw the original that has been digitized at least at 
the same rate at which they currently withdraw the original that has 
been filmed.  That rate may actually be higher, as the selectors will 
choose digital conversion knowing that the original will be 
disbound, and that there will be little chance it can be rebound.

	This Library's participation in Making of America, Phase I, 
was designed from the start to retain the digital file and withdraw 
the original.  A paper facsimile from the digital file will be printed 
only when a user requests that service.  Staff directly involved with 
the project have had the time and opportunity to achieve a  level of 
comfort with that project design.  It will certainly be necessary to 
give to staff at all levels, in all units of the Library, the time and 
opportunity to find their own comfort levels.  To assist in the 
process, a working group has been pulled together from staff in the 
Preservation Division, Digital Library Programs, Systems Office, 
and  selection staff to identify and analyze issues surrounding the 
use of digital files as a preservation medium and to recommend 
guidelines for the selectors to use when making both the decision 
to choose the option of conversion to digital format and the final 
disposition decision for the original.  This group, the Digital Brittle 
Books Task Group (a.k.a. Brigital Books), will hold open 
discussions with and conduct training sessions for all selectors.  

	


Carla J. Montori                         cmontori@xxxxxxxxx
Head, Preservation Division              phone:  313-936-2402   
University of Michigan Library             fax:  313-763-7885