Master black channel - separation parameters

In Photoshop, you can control the separation parameters to solve the different requirements for maintaining detail, color, and contrast without increasing the total amount of ink. In Photoshop 5.5, this command is in: File-Color Settings-CMYK Setup. In earlier versions of Photoshop, it was in: File-Preferences-Separation Setup. There are three main methods of color separation parameters: GCR, UCA, and UCR. Below we introduce separately.

GCR: Gray component substitution (with black ink instead of neutral ash composed of CMY)

The meaning of GCR is this: In the CMY color, it is often the two colors that play the dominant role that determine the nature of the hue, while the third color is called the gray component, which only serves to increase the black color. For example, red is mainly composed of color and yellow. If you add a certain amount of cyan, the red color will be darker. When there is too much cyan color, the red color will be dirty. Here, red is the main color and cyan is the gray component. Of course, the gray component also refers to a roughly equal amount of CMY tri-color combinations in one color, which constitute a neutral gray. With black, you can safely replace achromatic or gray components in a color. Please refer to the previous article "Mastering the Black Channel - Understanding Black" to perform GCR color separation and replace the extra color (neutral gray component) with the appropriate black color. This method can effectively reduce the total amount of ink, and help reduce the color cast, especially for skin color, fresh fruits and vegetables, metal and sky-based images.

In most cases, UCA base gain is not used when performing GCR color separation. Black helps keep the color of the main color change area (most importantly the contour area of ​​the image) clear. Black ink will increase dramatically in dark areas because it is difficult for the eye to distinguish the color changes in the dark areas. To maintain rich and vivid colors throughout the entire tonal range of the image, using the GCR separation method is optimal.

UCA: Background Gain (Maintaining Color Saturation in Shadow Zones)

GCR is the main method we love to use in color separation. But its disadvantages are: lack of detail in the dark tone area, and black is relatively monotonous. Especially dark-tone-based images such as night scenes. Using UCA color separation technology can make up for its deficiencies. UCA color separation removes some black in darker colors, while adding CMY tris, it is the opposite of GCR processing, but it only works in the darker color areas, and the degree of adding three colors is up to you controlling. The higher the amount of UCA specified in the GCR separation, the higher the degree of replacement of shaded black with CMY.

For low-key images such as night scenes, their midtones are close to the shaded areas, but the tone of the intermediate tone is very rich and vivid. Such images should be added to the UCA so that a certain amount of CMY components in the midtones can be maintained. , that is, keep the details of the midtones. At this time, you should also pay attention to the setting of the total amount of ink. To increase the tristimulus value will inevitably increase the total amount of ink. Different printing methods, different types of paper, and restrictions on the total amount of ink are different.

UCR: Underline Removal (Aggravate Shadows)

GCR replaces CMY neutral gray in any hue range with black, and UCR is black that is replaced in dark areas. It is used to reduce total ink coverage in shadowed areas while enhancing detail. It is very suitable for high-speed printing, because the fast printing ink drying time is very short, it is easy to cause the shadow details to be blurred. The main disadvantage of UCR is that dark tone appears to be monotonous and lacks contrast, which is why dark gray tone-based dark tone images cannot achieve the best results. Therefore, when images contain rich midtones and shadows, it is best to use a combination of GCR and UCA.

Several other settings

The above is an introduction to the three separation methods. When setting separation parameters in Separation Setup, there are several parameters that are also discussed here. The first is Black Genaration (black generation). This item is only valid when GCR is selected. The popup menu specifies the degree of Photoshop generated black version. Light (mild) black version is less used, and heavy (heavy) black version is used more often. Selecting None produces no black version, and Maximum is black version. If you choose Heavy or Maximum, you can add CMY components through UCA.

Black Ink Limit: The maximum amount of black ink that the printed paper can withstand. The default value is 100%. If you increase the UCA value, you should also reduce the amount of black ink.

Total Ink Limit: The sum of the maximum four ink colors that a printed sheet can exhibit. Using it to subtract the amount of black ink limit, the limit of the total amount of CMY tricolor ink is obtained.

Make advanced PDF files

With Pagemaker you can create an advanced PDF file that can be used for easy directory navigation.

first step;
1. First you must install Adobe's PageMaker 6.5, which is a tool for making PDFs! It is a document layout editing tool for Adobe's housekeeping. Powerful, it can typeset and produce beautiful pictures and texts, which is suitable for large-scale document typesetting and printing. Exporting a PDF file is only a small branch of its many functions. I'll take this out now and use it to make beautiful PDF files. At the same time, it must be noted that when installing PageMaker 6.5, Acrobat Distiller is indispensable for custom installation options. The key to its function is to convert PS files into PDF files.

2. Then you must have a Postscript printer for PageMaker. The printer driver must include a PPD file. (The PPD file provides information about the user's Postscript printer. It includes a list of the printer's native fonts, paper sizes, screens, and resolution capabilities. This information is provided by the printer manufacturer and reflects the most common configuration of the device. If you do not have PPD file support, you must find the manufacturer to upgrade your printer program. Having said so much nonsense, think carefully about the friend who specifically bought the Postscript printer? Is there no printer? Obviously there are ways! In fact, the solution is very simple. (This is the short cut that I took a long time to study!) You can install a new hardware in Windows 98. Just find a printer driver that supports Postscript. Install it on your system! You don't even need to have it. Any printer!! But what kind of printer support Postscript? Tell you! KODAK series can. (I use KODAK Color Ease PS Printer).
The second step;
Well, with the first steps in place, you can start making PDF files! There are no extra texts or patterns in the example. In fact, the operation of adding text patterns requires you to be familiar with PageMaker, its operation is not too complicated, and it is similar to other typesetting programs. I will focus on how to create a more complex document that contains multiple interfaces and can be navigated through directory navigation.

1 Start PageMaker, file--new--the following interface appears; This is the page setup interface for text. Note that I set the page number of the file to 5 pages and the start page number to 1. This point is more important. When generating a PDF file, the start page must be 1 in order not to cause coding confusion.

2. Then you can freely edit the documents you need in PageMaker's editing interface. PageMaker's editing features are powerful. You can insert frames of various sizes anywhere on the page. And arbitrarily move to a random position. You can easily insert various formats of graphics, documents, links, and even QuickTime format animations. How to vividly use PageMaker's powerful features to produce a beautiful document is to fully accompany your artistic ability. I will not introduce one by one about the specific operation of PageMaker, and a friend in need can consult the relevant instructions. I still talk specifically about our specific question - how to create a text containing a directory index. Now, for convenience, we have created a document with five pages. The first page we are free, as a directory guide page. Suppose we start editing the document from the second page. We first select the second page, use the area tool to draw a rectangular box, and then use the text input tool to locate the box, enter the text 1 LEVEL. Then select the rectangle as a whole, copy one, and paste them on the third, fourth, and fifth pages, respectively. Finally, edit the text box and change it to the corresponding title. After the title is edited, you can insert various texts, graphics, and animations you need in other places, depending on your personal preferences.

3. Next is the key to the entire directory design! Our goal is to automatically generate a directory that can be hyperlinked. Now we set it up. First select type--paragraph to set the paragraph properties. Be sure to select "Include in table of contents" wherever the mouse is pointed, and allow it to be added to the directory (important!). Then we select type→define styles to edit a paragraph style. You can design a new style based on your own requirements for the title section, or you can edit a new style. The main thing is to be sure to select the paragraph option when editing, and the same choice "Include in table of contents". Finally, we need to select each title box in turn. Note that after inserting the text edit input point in the title box, select type--style--"you edited paragraph style". (For convenience, I have chosen Handle.)

4. Now we can generate the title list automatically! Select Utilities - Create TOC (Create table of Content). Select the properties of the directory in the following dialog box. You can define the name of the directory and the page number that does not need to indicate the title. We select Page number after entry, and we compile the page number after the directory search. Select the first page and place the directory box in the appropriate place. If nothing else, you should see the directory below. (Okay, our editorial work ends here, remember to save it! You can take a break, drink saliva, and then move on to the next section to complete the output of the PDF file?br /> Three steps;
You're done! Before you can output PDF text, you can set the printer's properties, which are not described in detail. Select file→export--adobe PDF. You will see the following dialog box; here you can set the properties and output control of the PDF file. The options are relatively simple, mostly related to the attributes of the font, control, and print page. You can Your own preferences need to be set. We checked include downloadable fonts to allow downloading of fonts. Select distill now to convert immediately. Select view PDF using, specify what to open the generated PDF text to browse, here we set to adobe acrobat 4.0 After setting, click export to start the conversion. PageMaker will automatically convert the edited page into a postscript PS file, start distiller to convert the PS file into a PDF file, and then automatically open the generated PDF file. You can see the effect of the generated file. A PDF text with a full catalog index is generated. Clicking the table of contents in the quoting window or browsing window, 1 level will be linked to the corresponding 2 pages! !1, 2, 3! is convenient and quick, and a more complicated PDF text is ready. How is it, directory quotations, full-featured, unique!

Source: Flying Bird Software Guide.