This case study shows that raster image data is inherently preservable, as a logical implication of content contained in these files. This presentation will address these issues through a report on a project to migrate images from Kodak's Photo CD technology to the now standard TIFF and the emerging standard JPEG 2000 format. Although Photo CD is not a truly obsolete file format, it has clearly become and also-ran in the file format race, and it is desirable to migrate these files to standard formats for use in image repository and delivery systems. Recommendations are made for insuring accurate migrations of image data.The Portable Pixmap (PPM) format was used to facilitate analysis of the iamge files. PPM was chosen because it allows the RGB values from the source file to be directly re-encoded into ASCII, rendering the binary content of a raster image file into an ASCII text file that indicates the RGB values in series for each pixel in the image. The resulting files were compared using text and numeric processing tools. Further comparative information about the binary files was gathered from image analysis software and comparisons of derivative iamge data.A secondary consideration addressed is the maintenance of image metadata across format migrations. Because of the different levels of support for metadata amongst the file formats considered, automated metadata capture and subsequent image processing may be greatly affected by migration. The means of retaining metadata during migration are considered, reflecting on the value of internally versus externally contained metadata.
Jacob Nadal, "Keeping the Bits in Place: A Case Study of Raster Image Migration" in Proc. IS&T Archiving 2005, 2005, pp 249 - 252, https://doi.org/10.2352/issn.2168-3204.2005.2.1.art00052