PHOTOSHOP system settings

The most important reason for the impact of color-accurate print copying is that the display's RGB color gamut differs from the printing ink's CMYK color gamut from the printing ink's CMYK color gamut, and the color will eventually differ depending on the output device and application software. For example, from one monitor to another, from one printer to another printer, file transfer between different software, etc., different results are obtained, so monitor adjustments, materials, etc. are required before designing using an electronic publishing system. Parameter settings, color separation settings, dot gain compensation schemes, and a series of system setup preparations.
This article discusses several issues involved in the system setting in the Apple system PHOTOSHOP5, and discusses some issues in more detail and makes more reasonable settings. The setting method of the PC using the WINDOWS95/98 operating system is similar.
First, the display settings and adjustments in ADOBE PHOTOSHOP image correction to ensure that the colors displayed on the screen and print the same color. To obtain what you see on the screen is the result of the final printing, you need to make a series of corrections. Calibrate the monitor first to adapt to the teletext system environment.
Adjusting the PHOTOSHOP's display settings will affect the on-screen display and image color mode conversion process. The image is displayed on the screen in RGB color mode. If the color mode of the image is CMYK, the color mode needs to be converted to RGB before it can be displayed on the screen. The display setting only affects the display effect of the image. Affects the data of the CMYK image; if the image is in the RGB mode, when the image is converted to the CMYK mode, different color separation data will be obtained due to the different display settings.
1, GAMMA settings are generally GAMMA settings through the ADOBE GAMMA control panel display, you can find the control panel in the Apple system "control panel".
Through the ADOBE GAMMA settings can produce a device description file that conforms to the ICC standard. There are two sets of ConTROL PANEL or step by step (STEP BY STEP, ASSISTANT) settings.
If you select ConTROL PANEL, multiple control boards are set up to be set up at the same time. See Figure 2. I input the device description file in turn, I said, adjust the brightness and contrast, select the monitor phosphor model, the GAMMA initial value and fine-tuning, white field settings. STEP BY STEP is the same as ConTROL PANEL. It can only be set up step by step with the help of a wizard, see Figure 3.
First, adjust the brightness and contrast of the monitor. Set the contrast to the maximum and adjust the brightness so that the small square in the middle is as dark as possible.
In the second step, select the type of phosphor used by the monitor. Most monitors use the TRINION standard.
The third step is to set and fine tune GAMMA values. The apple system selects MACINTOSH DEFAULT under GAMMA, which means the GAMMA value is set at 1.8. Then fine-tune the slider to make the gray value of the central area of ​​the square look the same as the gray value of the surrounding area. When performing fine adjustment, a single grayscale block or RGB three-color grayscale block can be displayed to adjust each color.
The fourth step is to determine the white field color temperature of the displayed hardware. When you know the color temperature of your monitor, you can choose the appropriate value.
You can also click "MEASURE" at this point and select it visually. The screen will turn black, and every day a square, at this time choose the most neutral one. Setting the display to a cooler or warmer color temperature by clicking on the left or right squares is done when the middle box is clicked.
The first step is to adjust the color temperature in the work field. You can select a value that matches the hardware setting of the display to match the hardware setting or choose a different value to adjust the monitor display.
Finally, complete the GAMMA settings, select BEFORE or AFTER to observe the changes before and after the GAMMA setup, enter the file name, and click FINISH to save the settings.
If you use a MACINTOSH machine and have a third-party monitor calibration program, either use a third-party program or use the tools provided by PHOTOSHOP instead of using both. Because the third-party program updates the PHOTOSHOP color space description file, if both are used, the basic parameters of some displays may be set through PHOTPSHOP 5 FILE - COLOR - STEENINGS - RGB SETUP. The setting parameters are the same as those set by GAMMA. See Figure 4.
Second, the ink parameters and separation settings In PHOTOSHOP 5 software, use FILE - COLOR SETTINGS - CMYK SETUP to set the ink and the number of sheets and separation settings, see Figure 5.
1. Custom Paper and Ink Parameters In the CMYK SETUP dialog box, select the type of ink used in the INK COLORS drop-down list. The default setting is to select SWOP(COATED) for INK COLORS. The dot gain value at the 50% dot is set to 20%. If the ink used is not available in the drop-down list, such as the inks in places such as Tianjin and Shanghai, the color parameters of the various inks need to be obtained by testing and proofing. Then select the custom INK XOLORS in the dialog box, input the color coordinate value of each color block, and re-dot GAIN value. The same ink parameters as the monitor settings will affect the image color mode conversion, such as the GRB-CMYK mode conversion. If the ink parameter is set after the image is converted to CMYK mode, the parameter setting only affects the display of the image.
We used Tianjin Tiens GS series ink in the experiment, so when the film was exported for the first time in the experiment, there was no ink parameter used, and the ink type (SWOP COATED) was selected. After the output proofing, the ink parameters used were tested. The actual ink and paper parameters are entered into the PHOTOSHOP software to replace the original settings so that the future RGB images can be accurately separated. Follow the steps below to adjust the custom ink paper parameter values.
(1) use PHOTOSHOP menu command FILE - COLOR SETTINGS / CMYK SETUP leads to the settings dialog box, as shown in Figure 5.
(2) Select CUSTOM under the INK COLORS drop-down menu in the dialog box to customize the input of the ink paper parameters. See Figure 6.
The dialog box shows the ink color of different CMYK combinations and the spring CIE chromaticity coordinates. The CIE chromaticity coordinates are the color definition standards supported by POSTscript. The ink and paper parameters in the ink dialog box are Y (brightness), X-Y (chromaticity) Coordinates) are expressed as values. The chromaticity value of the ink is measured with a colorimeter under standard observation conditions of a D65 light source and a 2 degree field of view. If there is no colorimeter, the color of the color patch can be adjusted to the color of the proof by visual means. The figure shows the data obtained from the proofs printed with Tianjin Ink. The luminance values ​​and the chromaticity coordinates of the solid patches, such as yellow, yellow, green, yellow, yellow, green, white, black, and yellow, plus yellow, measured from the printed sample sheet, are input into the corresponding text box. .
In most cases, the ink will not produce a large hue difference on the same type of printer or printer, but it may produce some dot gain differences. Therefore, it is generally not necessary to perform ink re-setting for another printer or printer of the same type, and it is only necessary to change the DOT GAIN value in the setting dialog box. With a series of image adjustment means, the belt can make the image display effect be the same as the color of the printed proofs, achieving the effect that the screen sees and prints.
2. Separation settings Separation settings control the generation of CMYK color versions. It includes black print generation methods, background removal of UCR (UNDER COLOR REMOVAL) or gray components instead of GCR (GRAY COMONENT REPLACE), and total ink control. To perform accurate and effective color separation on an image, it is especially important to adjust the color separation settings in addition to the tone color adjustments.
When PHOTOSHOP converts an RGB image to CMYK mode, the program changes the RBG value to the CMYK value (using the RGB SETUUP, CMYK SETUP setting parameters, including the color separation setting in the CMYK setting), and the monitor and printing ink settings determine the screen color. Matching the printing color as much as possible, the color separation setting determines which precise CMYK is selected to replace the RGB color. Once the image is already in CMYK mode, PHOTOSHOP displays the CMYK image on the RGB display through internal conversion, and stores the color separation settings and ink set in the color separation table.
(1) The black color generation and color separation type color separation is a process of converting three additive colors (red, green, blue) into three subtractive colors (cyan, magenta, and yellow), and theoretically speaking, cyan, magenta, yellow, etc. The amount of mixing can be black, because the ink hue impure, resulting in blue, Lu, yellow three-color mixing is not black but gray-brown. In order to overcome this defect, it was necessary to remove some overlapping parts of cyan, magenta, and yellow during color separation, and add black to create a black plate.
A certain color is converted from RB mode to DMYK mode, and GCR (gray component instead of GRAY COMPONENT REPLACE) or UCR (background color removal UNDER COLOR REMOVAL) can be used. In the UCR background removal, the black plate is used to increase the dark tone area and the neutral color area; in the GCR gray component replacement, the black plate is used for a larger color range and the color is better than the UCR color separation. The use of GCR can better maintain the balance of printing ash. However, where to use the separation method is determined by the type of paper and printing requirements.
(2) Adjusting the black generation method and the color separation method In most cases, the PHOTOSHOP color separation default item can produce very good results. However, sometimes it is necessary to use the color separation dialog box to change the black print generation method, set a new total amount of ink, and change the background color removal mode. The settings made work when the image is converted from RGB mode to CMYK mode. However, non-POSTscript printers (such as HP DESKJET, CANON BUBBLEJEET, EPSON COLOR STYLE, etc.) produce their respective black amounts, and the separation settings do not work for these printers, that is, they do not affect the output.
Select the menu color separation setting command (FILE/COLOR SETTINGS/DMYK SETUP) under the PHOTOSHOP software. In the SEPARATION OPTIONS area, you can set color separation options, as shown in Figure 5. The appearance of gray gradations in the neutral image of the adjustment image can be displayed. In the figure, the horizontal axis represents the neutral gray value, from 0% (white) to 100 (black), and the vertical represents the generation of a certain gray scale. Neutral gray is generated according to various ink amounts, resulting in gray values ​​and cyan values. Roughly equal.
(3) Choose color separation type PHOTOSHOP lack of GCR to generate color separation, when you need to use UCR, click the select button to change the black generation mode. When using GCR for color separation, select the amount of black print, the total amount of ink, and the base color removal option. You can choose from a few black generation BLACK GENERATION settings. Among them, NONE does not produce a black version, LIGHT produces a smaller amount of black, HEAVY produces a relatively large amount of black, MEDIUM produces a moderate amount of black, and MAXIMUM directly substitutes the gray component for a black version, resulting in the largest amount of black. In most cases, MEDIUM can produce better results.
Using a custom CUSTOM allows you to manually adjust the black generation curve, see Figure 7.
If you need to use a custom item, first select one of the black generation options (LIHGT, HEAVY, MEDIUM, MAXIMUM) that is closest to the requested black generation, and you have a starting point for the black generation curve. That is, how large is, for example, the amount of black produced. The use of LIGHT, MEDIUM, HEAVY starts from 40%, 20%, and 10%, respectively, to generate a black version. Select Custom in the black generator, locate a point on the curve, drag the point to adjust the black curve, and the blue, yellow, and yellow curves will automatically adjust with the newly generated black curve.
(4) Select black ink amount and total ink amount control The black print generation will be based on total black amount control in the color separation setting. The default black edition is limited to 100%, and the total ink amount is limited to 400%. These limits determine how the CMYK curve is formed.
(5) UCA Underlay Gain UCA (UNDER COLOR ADDITION) The background gain is used to remove the black (K) component of the shadow cloud region and add it to the color component (CMY). This school building is richer and darker. Shadows. Increasing the UCA value increases the amount of CMY in the shaded area.
To print separation images, you need to have RGB, L