On the whole, most photo-buyers have traditionally preferred to call stock agencies to find the images they are looking for. There have been many reasons for this.
In general, most people like to associate with large brand name agencies (just like you might like to associate with name brands items in your supermarket). At these agencies, the quality of photography has been found to be consistently good, so photo-buyers usually know that if they can find the subject they are looking for, it will usually be good enough to please their clients. These large general agencies have allowed for one stop shopping, making it easier for photo-buyers to find everything they need with a single phone call.
In addition, the larger photographic libraries have had the fiscal resources to regularly produce expensive four-color catalogs and have usually permitted photo-buyers to scan images out of these catalogues for free comp use. This has generated extra sales by enabling images to be pre-approved for use by clients before photo-buyers even got on the phone to call for the original transparencies (Pickerell and Child, 1994).