The demand for accurate color reproduction has never been as high as it is today. Not only in the high-end electronic prepress market, but also in the desktop publishing and home office markets, the availability of both input and output devices is increasing rapidly.Most of the input devices today capture positive originals: scanners capture either reflective or transmissive originals; digital cameras are capable of capturing real life scenes as well.In some market segments (such as, e.g., the newspaper environment), there also is a definite interest in scanning negative originals. Especially with the new emerging APS standard for film (where manual manipulation of the film strips is no longer necessary), the demand for negative scanning will also increase in the home office market.Scanning negatives, however, is a very delicate process. Not only the input device should be characterised properly, but also the negative film itself is a parameter which needs to be studied carefully. On negative film, the information is stored inverted and due to the color dye layers within the negative film, there also is a density shift between the red, green and blue planes. The main problem, however, is caused by the fact that, due to the variations in the development process, the characteristics of a strip of developed negative film can differ considerably from other strips of the same film type.In this paper, we first give a brief survey of our approach to scanning negatives presented in the past. Then, we show how the unpredictable properties of negative films can cause this approach to fail and discuss some substantial improvements. In this respect, we show how the adaptive approach taken in the conventional photo-finishing environment can be used electronically. In a following section, we describe how the inverted positive image data can be transformed into a well-known, calibrated color space. In the last section, we briefly discuss the minimal requirements for an ideal negative scanner.
Chris Tuijn, "Scanning Color Negatives" in Proc. IS&T 4th Color and Imaging Conf., 1996, pp 33 - 38, https://doi.org/10.2352/CIC.1996.4.1.art00010