The color characterization of professional imaging devices typically involves the capture of a reference color target under the scene-specific lighting conditions and the use of dedicated profiling software. However, the limited set of color patches on the target may not adequately represent the reflection spectra found in the scene. We present a solution developed in collaboration with a camera manufacturer for the automatic color characterization of the sensors without the need of a physical color target. The optimal color transforms are computed based on the individually measured sensor spectral sensitivities, computer generated sets of color spectra forming a virtual characterization target and a mathematical model of the camera. The use of a virtual target enables the optimization of the color transform for specific image capturing situations by selective generation of the reflection spectra.
In the archiving and museum communities, the long-term preservation of artworks has traditionally been guaranteed by
making duplicates of the original. For photographic reproductions, digital imaging devices have now become standard,
providing better quality control and lower costs than film photography. However, due to the very short life cycle of
digital data, losses are unavoidable without repetitive data migrations to new file formats and storage media. We present
a solution for the long-term archiving of digital images on color microfilm (Ilfochrome® Micrographic). This extremely
stable and high-resolution medium, combined with the use of a novel laser film recorder is particularly well suited for
this task. Due to intrinsic limitations of the film, colorimetric reproductions of the originals are not always achievable.
The microfilm must be first considered as an information carrier and not primarily as an imaging medium. Color
transformations taking into account the film characteristics and possible degradations of the medium due to aging are
investigated. An approach making use of readily available color management tools is presented which assures the
recovery of the original colors after re-digitization. An extension of this project considering the direct recording of
digital information as color bit-code on the film is also introduced.
Many contemporary art collections contain important art installations where artists have used 35 mm slides as the primary medium. The number of ours these works are on show makes it necessary to regularly change the slides due to light fading. With funding from the Henry Moore Foundation. The conservation department at Tate initiated a project to examine ways in which digital technology could be used to aid the conservation of these works. The aim of the project was to place the original slides in cold storage and explored the possibility of using digital technology to make duplicate sets for display in the gallery. The reproductions needed to be of very high quality both in terms of resolution and color management. This paper discusses the use of densitometry to calibrate both device dependent and device independent systems for digitally reproducing 35 mm slides using a scanner and a film recorder and the effect of metamery when using slide films which employ different dyes.