Operation method of the most popular Agfa plane sc

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Agfa flat scanner operation method

at present, Agfa flat scanner is used by more and more users. However, in the process of use, because the operator is not familiar with the basic principle of AGFA scanner fotolook color separation software and lacks the necessary pre press basic knowledge, the data of the scanner software is not set normally, so that some functions of the scanner are not fully applied. Therefore, the quality of the scanned image is not satisfactory, and the stable image quality can not be obtained. Therefore, first of all, it is necessary to understand and be familiar with the main functions of AGFA scanner color separation software, which will be of great help to improve the image scanning quality. Earlier versions of fotolook2.08 can only scan image files in RGB color mode. However, fotolook3.0 can perform all image files including CMYK color mode. It should be noted that the PC version and Mac version of AGFA flat scanner are different. The method of scanning on PC version tends to be more like "fool". In Mac version, it has the function of image quality control similar to roller scanner. So it can effectively adjust the image quality. Therefore, when using Agfa flat scanner, the operator should first understand the different operating characteristics of the two versions of operating software. The two versions of software share the following four functions:

range - select the density range of the original

tonecurve - adjustment of tone curve

sharpness - data selection of virtual light mask

descreen -- moire removal of printed matter

The difference between the PC version and the Mac version lies in the fact that the former has a gradient correction setting falavors, a quick tool, and a sprite based on color adjustment. It focuses on the major aspects of the image to be adjusted. In some subtle layers and individual colors, it still needs to be adjusted through the relevant functions of Photoshop. The Mac version also has a color adjustment function, which can slightly adjust individual colors like the electronic color separation machine. Therefore, using this function can confirm the color before scanning, so as to effectively control the quality of the image. In addition, it also has the function of adjusting the picture hierarchy separately, so that it can easily control each point on the hierarchy curve accurately. Therefore, the Mac version is easier to control than the PC version in terms of scanner operation functions

I. color separation mode setting of Photoshop processing software

when the Agfa scanner driving software under the Photoshop environment is executed, the color separation mode of AGFA scanner and the distribution of points will be affected by the color separation mode and ink setting in Photoshop. The setting depends on the printing conditions, the ink type used, and the purpose of the printed matter. The following is the data setting under general printing status:

select GCR for color separation mode

printing ink type is big Japan ink or Toyo ink

the enlargement rate of printing point is 12-15% according to the printing conditions

the total amount of ink is 325-36o%

the maximum area of black plate is 6o-75%

the gradient curve of the black version is bright or self-determined according to the printing situation. According to the general printing conditions in China, it is suggested to move the starting point of the black version to 5o% or use light. This is beneficial to the embodiment of medium and high-profile levels and the maintenance of color purity. (see "GCR and UCR in color separation method" in printing magazine 98/8 for details)

the correct setting of the above items will enable the scanner to achieve ideal mode conversion, especially when the neutral gray balance is close to the required data, so as to avoid wasting more time when adjusting the neutral gray data of the scanner. In addition, it should be noted that the device profile of the color management system in fotolook It is recommended to set the data in this regard in the "light GCR 36oucr CMYK Japan" item. Meanwhile, the profile in Photoshop should also be set in the same state. In this way, the color display screen can display more correct colors and the color printer can print more consistent colors with the display screen. Profile is a part of Adobe's color management CMS. When cm stable is used, the color separation method will not work

II. Range setting: in essence, it refers to the calibration on the electronic color separation machine. Confirm the brightest and darkest areas on the original. Agfa plane scanner scanning software provides three different methods for operators to choose. They are automatic, Dmax/Dmin, and shadow/highlights

1. Automatic setting: (automatic)

in this mode, the scanner will automatically find the bright and dark parts within the preselected image range. That is, the "Ai" function. However, it is only used when the original status is basically normal. If the original is too dark or too bright, the scanned image will also be too dark or too bright. At the same time, it just copies the original image and cannot correct the color deviation. It should be noted that when operating this function, attention should be paid to whether the range of image selection is appropriate. If the outside of the original is also selected in the image range, the scanner will include the black part on the cover plate. If the density of the black part on the cover plate exceeds the maximum density of the original, the image will be slightly lighter than the normal scanned image, and the image will lose its due contrast. Similarly, when the white paper part that does not belong to the original is also selected in the image range, if the density of the white paper part is lower than that of the original, the image of the original will be darkened due to the large dot area of the high-profile part, and the image will lose its due contrast

2. Set the original density range: (Dmax/Dmin)

the general normal density range of the transmitted original is between o.12-o.25 for the bright part and 2.8-3.5 for the dark part. The normal range of the density of the reflected original is 0.07-0.12 for the bright part and 1.5-2.0 for the dark part. The selected original density range should be roughly determined according to the original type, the materials used in the original, and the performance content of the original. Whether the calibration is normal can be confirmed according to the number of calibration points displayed by the scanner

it is difficult to correctly observe the density of the original with the naked eye. In the current situation, the general scanning operation lacks a densimeter to measure, so it is difficult to correctly grasp the actual density of the scanned original. At this time, the scanner can be calibrated in automatic mode first, and the scanner will perform a pre scan. Then open the function key original density range. At this time, the mode will display the density data of the highlight and dark part in the automatic mode. The operator can make appropriate adjustment according to the displayed data, so as to obtain more correct calibration density data. According to the original density calibration, the scanned image of the original copy of the original color can be obtained (neutral gray, when the hierarchy curve setting data is normal), so it can better preserve the hierarchy of the original. Restore and copy the original and adjust the contrast of the screen appropriately. In particular, for some originals that are difficult to determine the calibration position without obvious highlights and dark tones, it is advantageous to use the density range function for scanning

3. Setting of white field and black field (white/blackpoilt):

this function is the original calibration described in the operation of the electronic color separation machine. It mainly relies on the ability of the scanning operator to judge the original, the familiarity with the color formation law of printing points, and the understanding of printing knowledge to input various color data on the original, and select the dark and bright positions on the screen through the mouse. The scanned image can have appropriate contrast and rich layers. And through the correct point quantity of yellow, red, blue and black, we can correct the high-key or low-key color deviation and get a good color copy

when this function is turned on, you can see a window where you need to input the yellow, red, blue and black dots in the bright and dark parts to give quantitative values. The input unit is determined by the scanning mode. When the scanning mode is CMYK, the area data in point is input. When the RGB mode is used for scanning, the input unit is a number between 0 and 255. It should be noted that although the PC version of the scanning software can also use the input data of C, m, y and k points, the black field fixed mark data can not be input normally, and the white field input CMYK data is not satisfactory. Because it is controlled by the color separation mode setting of PHTOSHOP. This is the same as that the earlier Agfa Mac version can only scan RGB mode files. After data input, use the right mouse button to set the calibration position at the high light and dark calibration points. At this time, the CMYK or RGB data entered by the operator will appear at the calibration position. CMYK and RGB calibration methods are described as follows:

cmyk calibration method: this calibration method is the same as the calibration method of general electronic color separators. It is usually selected at the neutral gray part of the highlight and dark part. Then, input the data that conforms to the neutral gray proportion of the printing. Ensure the safety of tires under the condition that the expansion rate of printing point is normal and the recovery of drying PS plate point is good; Other data bright spots of the tire that can be monitored shall be 3-4% in the blue version and 2-3% in the yellow and red version; The dark spots are 88-92% for the blue version and 82-86% for the yellow and red versions. It should be noted that the so-called bright part refers to the highlight part of the picture, rather than the brightest extremely high light spot. The former is the diffuse reflection of the light on the object, while the latter is the reflection of the light on the mirror object, such as glass, water, metal and other objects. The reflection on these objects is only one or a few dots on the whole picture, and the area of the dots is very small, accounting for only a small part of the picture. During calibration, these parts cannot be used as high light parts as calibration points. In order to reflect the texture of the picture, these extremely high light points should be treated as absolute areas. At this time, it should be noted that the calibration position must be neutral gray, otherwise the original hue of the image will be changed. If it is confirmed that there should be a hue that deviates from a certain color in some parts, the proportion of a certain color of C, m and y should be increased as required during calibration. Correct white field and black field calibration can also effectively correct the color deviation of high-profile and dark tones of the original, and make the picture get proper contrast

rgb calibration method: the principle of this calibration method is the same as that of CMYK calibration method, but their calculation units are different. According to the principle of light additive method, the same amount of primary color light is mixed to obtain a brighter white light than the original. Therefore, the equivalent order of RGB light is 255 as the brightest and zero as the darkest. When using the scanner for calibration, the white field should make the amount of R, G and B equal. Similarly, the amount of trichromatic light should be equal in black field calibration. When it displays the dot area, it will be affected by two factors: first, the color separation method under the color setting in Photoshop. The second is affected by the printing ink setting in phtosho solution P. Therefore, the above two items should be set correctly according to the printing conditions when using RGB light unit calibration. Otherwise, when the scanned image is converted to CMYK color mode file, there will be too many "super gamut" colors and it will become gray and lack of hierarchy and proper picture contrast.

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