How to properly scan the film

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.

135 film requires a high-precision scanner to complete the scan. 135 film format itself is very small, the film range is only 24 * 35 mm, and in practical applications, the user usually needs a large format picture. Therefore, in order to meet user requirements, high scan accuracy is required when scanning negatives. For example, if the user designs the scanned image as a prepress, the image format requires a 3-inch color effect, that is, the film is magnified three times. Then, when scanning the image, the resolution setting should not be less than 900 dpi at least. Therefore, the film scan can only enter the practical stage when the scanning accuracy of the scanner itself reaches 1000 dpi or more. At this time, the film scanning can achieve an accuracy of 1280*768 dpi pixels. The conversion method is as follows: 135 The area of ​​the negative film is 36*24mm, which is 1.5*0.9 inches. The actual size multiplied by the resolution, the pixel is 1350*810dpi, taking into account the loss of focus accuracy of the scanner, about 1280*768dpi pixels . For other applications, such as personal viewing, network transmission, and film scan accuracy, it does not need to be high. Currently used for pictures on the website, the scanning accuracy can be below 600*400dpi. $Page break $

How to control the scanning effect in the driver software

In general, the driving software of the film scanner is an adjustment tool capable of providing color, brightness, and the like. For example, the new professional film scanning software SCANWIZARD PRO TX of Microtek, not only combines the professional drive of MICROTEK and the powerful CMS color management system built-in, but also has different specifications of the film property files of many film manufacturers in the world, which can control the scanner to the film. The exposure time includes a variety of input/output device color profiles to ensure consistent and accurate scanning colors. When users scan the film, they mainly use the tools provided by the software to achieve the best color adjustment effect.

For example, when the user scans, the default parameter is AUTOMATIC RANGE. This function automatically adjusts the brightness of the content within the frame selection range based on the content of the “prescan” image. The user only needs to change the content of the frame selection before the scan to select the scan range. For some underexposed negatives, the selected range preferably contains a portion of the film base (black) so that better color reproduction can be achieved.

For under-exposed film, we can directly select the function of UNDER CATALOG below UNDER EXPOSED in SCANWIZARD PRO software to directly adjust the brightness of the image.

We can also select GAMMA in the GRADATION tool and adjust the darkness of the image by adding a GAMMA of about 1.8.

For some colors with color calibration, the user can use the TONE CURVE curve adjustment tool to adjust the R, G, and B channels. However, it should be noted that the reduction of blue color is to add yellow; the reduction of red color is to add cyan; the reduction of green is to increase magenta.

If there is a clear reference color in the picture, such as a white wall, a neutral gray concrete road, the user can also use the function of REMOVE CAST to adjust the color shift.

Source: Tianji Business