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Help & guidance Guides to Good Practice

Current issues and concerns

Kieron Niven, Archaeology Data Service / Digital Antiquity, Guides to Good Practice

One of the most obvious issues with digital raster images is the wide range of formats available in which images can be created and stored. Raster image formats can vary massively in terms of individual features and capabilities and can cover the whole gamut of format types from proprietary, software specific formats through to open standards. A key component of this assortment of file types is also the range of individual features and capabilities each file format possesses – such as compression (lossless or lossy), colour depth, support for transparency, embedded metadata – and it is important that an appropriate file format is chosen for the image being created both during the data creation stage and for long-term storage. In addition, in certain project workflows, images may change formats at different points in the project depending on how they are being used. In these scenarios it is also important to be aware of what range of functionality and metadata each format supports and what could potentially be lost during each format migration.