Tania Durt of the Spruce Project imaging a specimen using a 'HerbScan' scanner
Digitisation of herbarium material involves the process of capturing data and images and storing them in digital form. Over the past 5 years considerable progress has been made in the creation of digital assets from the herbarium collections, and in the dissemination of this information. The digitisation process allows for our collections to be queried and analysed in ways not previously possible, and enables access by 'virtual visitors' unable to visit the collections in person.
Cataloguing the Herbarium Collections
Kew has implemented an electronic catalogue for our herbarium specimen collections, known as HerbCat. HerbCat is a relational database which stores information about the specimens including collection details (where, when and by whom) and naming history (what taxon has this specimen been assigned to now and previously, when and by whom). Other information such as the part of the plant collected, related material in Kew's collections and any restrictions on the use of the specimen, are also recorded where appropriate. Each specimen is given a unique barcode and represented as a separate record in HerbCat.
Since June 2006 the HerbCat database can be consulted outside of Kew via the internet (Herbarium Catalogue). The number of specimens currently stored in the database are given on the Herbarium Catalogue pages.
In addition to capturing specimen label data and other information about the specimens we are also now capturing digital images of many of our specimens.
The primary objective of storing and providing access to digital images of our collections is to facilitate access to the collection. Storing high quality images also has the potential to aid long-term preservation of the collection, by reducing the demand for direct handling and loans of the physical specimens. To image our dried herbarium specimens Kew has adopted 'HerbScan': a mobile frame in which a standard flat-bed scanner is held in an inverted position, with a rising bed mechanism that brings flat upright specimens to the scanning surface. This simple, cheap technology has made it possible to create high quality digital scans of flat herbarium material whilst avoiding damage to the specimens..
The specimen images stored are TIFF format images of high resolution (600 pixels per inch). This quality of image allows users to view original label data as well as morphological detail which could otherwise only be accessed by viewing the specimen itself. Prior to 2005 Kew used older imaging technology (high quality analog copies e.g. Cibachrome) but production of Cibachromes and microfilm has been succesfully replaced by digitisation.
Images are stored internally on an archival quality server (which is mirrored for security purposes) and made accessible internally through Kew's image server database, or externally via the Herbarium Catalogue. For performance reasons the images available across the internet are smaller (120 pixels per inch, JPEG format).
Information and links to some of the individual herbarium digitisation projects underway or completed at Kew are provided in the Herbarium Catalogue project pages.