Correct film scan

Film scanners, also known as film scanners, have the task of scanning a variety of transparencies and generally have high optical resolution. Compared with traditional photo scanning, film scanning not only greatly reduces the cost of use, but also reduces errors, improves accuracy, and saves users a lot of time. In view of the above advantages, the film scanner has been more and more widely used in China, but many users often encounter such problems in the process of using the film scanner, so that the desired scanning effect cannot be obtained. What should you watch out for when using a film scanner? What kind of use is correct? This article will be discussed with the user.

Basic factors to consider in film scan

The film itself is equipped with a film base mask, which requires manual color correction when scanning. The film itself has a film base mask, (because the film uses an organic dye process, because the film is not a transparent white as we imagine, but colored, as if there is a layer of color enveloped on it, called a color mask.) And The base color of different manufacturers is different. In addition, the exposure latitude of the negative film itself is very large. Generally, two exposures can be overexposed. Therefore, when scanning the negative film, it is not possible to perform the correction of the scan to the standard photograph by using the standard color film. Before scanning the film, the user needs to manually adjust the film, such as pre-scan image, color correction (hue change), exposure correction (brightness level) and color saturation processing, so as to fully meet the user Needs. The following figure is a common film-based situation:

The scanner needs to have a certain density value and the film scan can achieve good color reproduction. The dynamic range is the brightest and darkest range that can be recorded in the case that each gradient can be clearly distinguished. The dynamic range of the general special-purpose film scanner is all above 3.2D, and professional products of Microtek can reach 4.2D or even higher. Ordinary platform scanners usually have a dynamic range of 2.4D or less and are generally not marked. Why does the film scanner have to have a certain density range? The reason is that the image on the negative film has a smaller contrast in brightness than the reversal film. Therefore, the input range of the scanner tone cannot be fully utilized. If the dynamic range is not enough, the scanned film is not a low light level loss or the high light level is affected. Only with a high-precision A/D device and a scanner with a good density range, can the image of the film be fully captured and displayed.

The following is a comparison of the tone range of the reversal film and the film. It can be seen from the above that the contrast of the film is 126, and the brightness contrast of the reversal film is as high as 219.