Digital Color Management: Encoding Solutions, 2nd Edition

6

Reflection Images

Scans of hardcopy images—such as reflection prints, photographic slides, still and motion picture photographic negatives, and motion picture prints—are an important input source of color information in many color-imaging systems. This chapter begins an analysis of the nature of such images with an examination of the colorimetric characteristics of images produced on reflection supports.

Reflection images can be produced by conventional and instant photography, graphic arts printing, thermal dye transfer, inkjet printing, electrophotography, and by a number of other technologies. However, regardless of the exact technology employed in their production, virtually all pictorial reflection images share certain fundamental characteristics and colorimetric relationships to original scenes. Those characteristics and relationships will be examined in the context of an experimental color-imaging system (Figure 6.1) consisting of a digital camera, a computer, a thermal dye-transfer printer, and a scan printer that writes directly onto conventional photographic paper. The system produces very high-quality images on both the thermal and photographic reflection media.

The test target that was described in Chapter 5 will again be used in the analysis of the system. As before, the target will be illuminated by a light source simulating CIE Standard Illuminant D₆₅. The test-target colorimetry will be computed from the measured spectral reflectances of its patches and the ...