Copyright of digital images needs to be assigned to client in the contract, and not retained by the bureau. Costs can be favourable compared to in-house costs. Lack of control over scanning environment. Range of scanning equipment available. Need to transport materials.
Bureau absorbs equipment depreciation and obsolescence costs.
Digital images need to be 'fit for purpose' and cost effective. A useful approach is to consider a two step process at the image capture stage of the digitisation chain. A digital master is scanned for preservation purposes. Subsequently, a digital derivative is created from this master for access purposes, to be delivered in a networked environment. One scan will not suit all purposes.