First, the abbreviation of Illustrator is AI (Adobe Illustrator). It is a product of Adobe, which also includes photoshop, etc. It is mainly engaged in graphic design. It is a graphic design editing software and a vector drawing software. Produce vector graphics (images are pixel images, graphics are vector graphics, which are different concepts), and can do small-scale typesetting, mainly in conjunction with PS to create advertisements, magazines, etc.
CDR is a vector drawing software developed by the famous Canadian COREL company, so CDR can record the file attributes, location, paging, etc. However, it has poor compatibility. It can be used in all CorelDraw applications, but other image editing software cannot open such files.
Corel Draw is widely used in many fields such as trademark design, logo production, model drawing, illustration drawing, typesetting and color separation output. Its functions can be roughly divided into two categories: drawing and typesetting.
To be specific, Illustrator is mainly a software commonly used by foreign graphic designers, and Coreldraw is a domestic design software. They each have their own advantages.
AI has strong compatibility, can directly support most file formats, and has sufficient support for printing. The disadvantage is that it is not as popular as coreldraw.
The differences are as follows:
Advantages of AI:
1. AI is better than CD in making illustrations. The main reason is that it can use layer mode (people familiar with photoshop should know how good this effect is) ). In addition, when filling the grid, AI can use a straw to directly absorb colors and then fill them in, but CD cannot do this.
2. The colors output by AI are more accurate than CD. This is common to everyone Known facts.
Advantages of CD:
1. More convenient to use. Easier to learn than AI. Many AI functions are very hidden and easy for beginners to find. Corresponding functions.
2. Supports various import and export formats (of course some are not very stable).
3. Nodes and control handles are displayed larger than AI and are easy to select. .AI gives people headaches. Personally, I am very disgusted with this aspect of AI
4. The typesetting and editing of multi-page text are more convenient than AI
2. Imposition is also called "layout". "Publication". The second step in manual typesetting. According to the layout design requirements put forward by the printing unit and according to the content of the original manuscript, the selected blanks and some typesetting materials are assembled into pieces of completed movable type printing plates of a certain size. Imposition can be divided into two types: imposition of parts and imposition of books and periodicals.
For example, business card imposition depends on how it is printed!
1. Printing and imposition
Generally, there are two types of business card printing paper: one is 195*297 mm bottomed pattern paper, and the other is A4 size color inkjet business card printing. Paper.
The imposition method is the same: 10 business cards per piece of paper, 2 per line, 5 lines per piece of paper. When making the imposition, leave space for cutting. It is recommended that the imposition gap is 2-5 mm.
2. Printing imposition
If it is a business card offset printing machine, the PS version is dedicated. Generally, each PS version can be put together up to 3 copies. If it is a spot color, each color It will be made into one version. If it is a full-color picture, it can only be made into a CMYK four-color version.
When putting together, pay attention to vertical alignment and printing corner lines to facilitate color registration. Leave 3 mm (2-3 mm for books, 3-7 mm for boxes) on the edge of each plate to avoid bleeding. Printing and cutting position.
Imposition is divided into manual imposition and computer imposition.
1. Manual imposition
refers to the manual way to orderly arrange the film. Neatly arranged, the requirements for human operation are quite high, and it has gradually declined and been replaced by computer software imposition.
2. Computer imposition
The main popular software is: imposition version The large version usually uses Kodak's Preps, and the small version includes QarXkess and Indesign; those who make color boxes mostly use AI (Illutrator), but also use Freehand, corel draw, and Adobe Acrobat (with the imposition plug-in qiplus)
3. Overprinting: refers to the requirement for overlapping registration of each color plate when printing multi-color printing;
Trapping: refers to the need for a certain staggered overlap between one color block and another color block to avoid The white edge is exposed during printing, so it is also called whitening. When two colors meet, the place where the two colors meet may be offset during printing, resulting in a white edge or color aliasing. Trapping is used at the intersection. The two intersecting colors will infiltrate each other a little, so there will be no white edges.
Embossing and overprinting mean the same thing, that is, one color block is overprinted on another color block. However, when printing, special attention should be paid to the overprinting of black text on color images. Do not hollow out the pattern under the black text, otherwise the white edges of the black text will be exposed if the printing overprint is not accurate.
Example: The four Ps are 16 karat, made with PS, and the text is K100. It was sent to the dispatch center and informed that the black text was not embossed, that is, the position of the black text was on other color plates. The top is hollowed out,
which will cause overprinting to be inaccurate and reveal white. In PS, black text overprinting is to change the layer mode of the black text layer to Multiply, so that in other color versions, the black text will appear. It is not hollow, so there will be no white spots. Friends who have just entered the printing industry and like to use PS for design must pay attention to this issue. In addition, they must develop PS for base drawings, CD or AI typing. good habit. In this way, the printed text will not have burrs.
Generally, the black color in CDs and PMs is the default imprint.
1. Do all bitmaps need to be overprinted or trapped? Because some customers directly give us bitmap files (some bitmaps are quite complex) and output them for proofing, and no color registration errors are found.
Answer: No~~~Overprinting can only be K100 black or graphic under certain circumstances
2. How thick should the line overprinting be to achieve accurate color registration? And printing? Is a trace (0.01 mm) enough? How much does it cost to convert into pt units?
Answer: The extremely thin line~~ is 0.2 points. 1pt=0.35146mm
3. Are the functions and principles of overprinting in CD and ILL the same? I seem to have heard that the thickness of the overprinted lines in ILL is half the thickness of the lines, is that right? What about on CD?
Answer: There is no such statement.
4. Is overprinting in ILL safer than CD?
Answer: Do it the normal way. Software is just a tool, there is no better or safer one.
5. Spot color overprinting, spot color and black, special color on top, black on bottom, should I use line overprinting? Spot color and black, spot color below, black above, do you use fill overprint? If we want to prevent "two kinds of black" from appearing and causing abnormal patterns, can we only use line overprinting? Or is there any other way? Or is it possible to register the colors without overprinting? Do spot colors have transparency properties? Then spot colors cannot be overprinted with fills and can only be overprinted with lines?
Answer: Relatively speaking, line overprinting is better.
6. Assume some kind of overprinting
Assume that in ILL, there is a pattern with a red filling in the middle, a green outline line, and a pattern with green filling at the bottom. Is it possible to do line overprinting (using The green outline lines on the same layer as red are overprinted with the green fill underneath)?
Answer: There is no need to overprint. Normal output is enough
7. If it is only CMYK, the pattern will be similar to the color insert in "Cartoon King", or the cartoon in "Tom and Jerry", the animated characters will have black lines Check them out to show their outline. Do we need to overprint such a complicated picture? Is it hard to imagine overprinting one color block after another? ! If there is no overprinting, how are those anime magazines printed?
Answer: Again, under normal circumstances, only black is overprinted, and other colors are output normally.
8. If the black outline on the artwork given to me by others is made by the method of "black leakage" (for example, there is a seam in the middle of one red and one green block, and there is a black block below the seam), Isn’t this kind of artwork too desolate that “you can only mark it once and then overprint it”?
Answer: Just use a piece of black under the seam for overprinting
In fact, overprinting is very simple, just remember one thing: generally only black words or black graphics are overprinted, and other colors will be output normally by default ~
If it is hundreds of pages like Heidelberg If there is only one printing truck, there is no overprinting problem at all. However, according to the national conditions of the country, many printing factory owners now do not have such good equipment, so there is a phenomenon that the printing truck prints inaccurately and has to overprint.
When overprinting strokes, we generally rely on experience. The filling strokes in large areas should be thicker, 0.1~0.2mm is appropriate, and the filling strokes in small areas should be relatively thin. After stacking the strokes, use a magnifying glass to observe the printed matter and sometimes you will find that the strokes have turned black. There is nothing you can do about it.
Fourth, the pre-coated photosensitive plate, referred to as the PS plate, is to apply photosensitive resin liquid to a specific surface in advance. On the base, after drying, store it like film. When necessary, take it out to dry and develop, and you can make a printing plate.
PS versions are divided into flat plates, letterpress plates and screen plates. Only lithographic PS plates are used in the light printing system. Ordinary PS plates can be divided into positive pattern type and negative pattern type according to the negative film used for printing; according to the different plate bases, they can be divided into aluminum base and paper base.
Generally, offset printing machines use positive pattern PS plates. The drying process of PS plates is simple, mainly through exposure, development, neutralization, plate revision, ink application, glue wiping, etc. After the process is completed, the drying process of the PS plate is introduced as follows:
Exposure: The negative with the pictures and text is closely combined with the PS plate to dry the plate. The exposure time is based on the photosensitive glue used in the PS plate. Varies. Determining the appropriate exposure time is very important for the quality of printing. Taking the positive PS plate as an example, if the exposure time is too long, the image on the printing plate will be too shallow, the dots will shrink, small dots will be lost, and the highlight will be seriously lost. If exposed If the time is insufficient, the image on the printing plate will be too dark, the dots will expand, and the dark-tone dots will easily become blurred. In order to determine the appropriate exposure time, control strips are often used, and the dot reproduction range of 3 to 95 on the printing plate is used as a standard. Commonly used control strips include Brunner control strips, in which the 50 fine mesh area is used for printing quality control. In the 50 fine mesh area, there are 13 pairs of yin and yang dots in the center. The yang dots are solid and the negative dots are solid. It's hollow.
Development: After the PS plate is exposed, it needs to be developed. The purpose of development is to remove from the plate the part that is decomposed by light and is soluble in a weak alkali solution. The higher the concentration of developer, the faster the development speed. Due to the different alkali resistance of PS plates, the composition and concentration of the developer are also different. The developer is generally composed of developers, inhibitors, wetting agents, etc. The developer is mainly used to dissolve the photosensitive layer and decompose part of the photosensitive agent and resin upon exposure to light. Since the aluminum plate base has relatively weak resistance to alkali corrosion, in order to suppress the development speed and prevent the developer from corroding the aluminum plate base, appropriate inhibitors are generally added. In order to enable the developer to evenly cover the layout and achieve uniform development, a small amount of wetting agent is also added to moisten the layout.
Neutralization: During development, put the exposed PS plate into the developing tank, so that the developer solution is completely immersed in the plate, and gently scrub with a brush until all the light-decomposed parts dissolve and fall off. Finally, take out the developed plate, rinse all the residual developer on the plate with water, and then neutralize it with 1~3% phosphoric acid aqueous solution. After neutralization, blow dry and you can proceed with revision.
Revision: The revision of the PS version mainly includes decontamination and patching. Decontamination mainly removes excess rule lines, negative film marks, tape marks, dirty spots, etc. on the PS version. For this reason, special dirt removers are needed to remove dirt. Use a brush dipped in dirt remover to apply on the excess photosensitive layer. The dirt remover will dissolve the excess photosensitive layer, and then rinse away the remaining dirt remover and dissolved substances with clean water. When flushing, the flushing speed must be fast to prevent the washed material from damaging the graphics and text. When replenishing the plate, blow dry the areas that need to be reprinted on the developed printing plate with hot air, use a brush to dip the repainting liquid into the area that needs to be reprinted, and then dry it with hot air at 60-70°C. The purpose of drying with hot air before patching is to remove the moisture from the areas on the plate that need to be patched, so that the plate patching fluid can firmly adhere to the plate.
Ink coating: In order to facilitate the inspection of the plate-making quality of the revised PS plate, the printing plate must be coated with PS plate development black ink. The purpose is two-fold. The first purpose is to prevent the printing from being damaged. The graphic part of the PS version is decomposed again by light, so that the finished version can be stored for a long time. The second purpose is to increase the ink absorption capacity of the inked part of the printing plate. The surface of the photosensitive layer of the PS plate is smooth and the ink absorption performance is poor. The ink cannot be absorbed quickly. After the special development black ink is applied, the photosensitive layer will form A good ink-absorbing layer, when printing, the printing plate will be inked quickly.
Glue wiping: Rub a layer of gum arabic on the printing plate coated with developing black ink. The purpose of gluing is to protect the layout, prevent dirt contamination, prevent oxidation of the layout, and also improve the water-absorbing and oil-repellent properties of the blank parts. Since gum arabic has the characteristics of water solubility and good adsorption, when it is rubbed on the surface and the water evaporates, the colloid will form a film on the surface. It is difficult for any gas and dust in the air to pass through the adhesive layer to prevent oxidation of the layout.
After the PS version has gone through the above drying process, it can be printed on the machine.
Fifth, the difference is that monochrome has only one spot color, such as leaflets that are often thrown on the street or at the doorstep, all black or all red, etc. In short, there is only one color
Two-color printing has two spot colors. For example, newspapers in the past, issued on holidays such as National Day, were usually black and red (nowadays newspapers are all full-color)
The difference in price is, of course, color The more, the more expensive it is. This refers to the price quoted by the printing factory. For a four-color machine or a two-color machine, there is not much difference in cost between printing one color and two colors. But if people don’t tell you this, they will definitely charge more. Of course, for a single-color machine, single-color printing only prints once, and double-color printing requires two printings, so the labor cost is doubled.
The setting you are talking about should be to set several spot colors during design, and just use the spot color output when producing the film
Six, spot color refers to When printing, this color is not synthesized by printing the four colors C, M, Y, and K, but a specific ink is used to print the color. Spot color inks are pre-mixed by the printing factory or produced by the ink factory. For each spot color of the printed matter, there is a special color plate corresponding to it during printing. Use spot colors to make colors more accurate. Although colors cannot be accurately represented on a computer, you can see the exact color of the color on paper through the pre-printed color swatch cards of standard color matching systems, such as Pantone Color Matching System, which creates very detailed color swatch cards. .
For non-standard spot colors set in the design, the printing factory may not necessarily accurately adjust them, and the accurate colors cannot be seen on the screen, so do not use them lightly unless there are special needs. Customize your own spot color.
Characteristics of spot colors
Accuracy.
Each color registration has its own fixed hue, so it can ensure the accuracy of colors in printing, thereby solving the problem of color transfer accuracy to a large extent;
Solidity. Spot colors generally define the color using a solid color, regardless of how light that color is. Of course, you can also screen (Tint) the spot color to present any shade of the spot color;
Opacity. Spot color ink is a covering ink that is opaque and can be used for solid coverage;
It has a wide color gamut. The color gamut in the spot color library is very wide, exceeding the RGB performance gamut, not to mention the CMYK color space. Therefore, a large part of the colors cannot be rendered using CMYK four-color printing ink.
[Edit] Reasons for using spot colors
In color dot printing, the characteristics of spot color inks are often used to select and use them. Generally speaking, it is generally used in two situations:
To print some visible light colors outside the color gamut of CMYK four-color printing ink on printed matter. The color gamut of CMYK four-color printing ink is obviously insufficient compared with the visible light color gamut, while the color gamut of spot color ink is wider than the color gamut of CMYK four-color printing ink, so it can express many colors other than CMYK four-color ink;
To make up for the shortcomings of printing technology. Due to errors in various processes in the overall printing process, equipment maintenance, operating environment, human oversight and mechanical wear and tear, it is difficult to obtain smooth and uniform dot colors when printing small dots below 153. At this time, we can use the same color By using full-page color registration (i.e. solid spot color) instead of small dots for printing, it is easier to obtain flat, large-area color blocks. In addition, sometimes in order to clearly express fine graphics and text, such as finer strokes of mixed-color graphics or white lines, spot color processing is often used so that fine lines can be expressed sufficiently realistically and delicately.
[Editor] Analysis of factors causing color difference of spot color inks during the printing process
The impact of paper on color
The impact of surface treatment on color
The influence of the lightening agent on the color
The influence of the difference in the density of dry withdrawal
The influence of the system difference
Problems that should be paid attention to when using spot colors
Unification of spot color color names. In different software, the names of the exact same two color schemes may be different. For example, FreeHand names PANIONEI 1F5 as PANTONE 1F5CVC or PANIONE 1F5CVV, while in PageMaker, it is named PANTONE 1F5CV. In this way, when the FreeHand graphic object is placed in PageMaker for typesetting, the same color will have three names, and three printing plates will be generated during color separation output, causing output errors. Therefore, if the data file needs to be used in more than two software, before the integrated color separation is output, you must pay attention: the names of the same spot colors must be unified. The more common method is to use the color names in the layout software as the standard, and rename the same spot colors to unified names in the palettes of various software.
The angle of spot color screening. Under normal circumstances, spot colors are printed on the spot, and dot processing is rarely done, so the angle of spot color screening is rarely mentioned. However, when using a light mesh color with a registered color, there will be problems in designing and modifying the screening angle of the spot color dots. If there is an overprinting area between the spot color of one dot and the colors printed by other dots, the angle of the spot color screening must be considered. At this time, if the angle formed by the screening angle of the spot color dots and the screening angles of other colors is less than 30 degrees, screen collision or moire will occur; if the angles overlap each other, it will cause ink overprinting problems, which will cause Severe distortion of print color.
In addition, the screening angle of spot colors is generally preset to 45 degrees in the software (45 degrees is considered the most comfortable angle for human eyes. Arranging the dots in a direction at equal angles to horizontal and vertical lines can reduce The ability of the human eye to detect dots), if it is a two-tone image or a data file that already prints four-color black, (generally in four-color screen printing, the black dots are placed at 45 degrees, yellow is 0 degrees, Magenta is 15 degrees, cyan is 75 degrees), and there are spot colors, or there are two or more spot colors, the output will be 45 degrees during color separation screening. Therefore, when using a light screen for spot colors, if There may be overprinting with other screening colors, so you must open the software color settings or print settings dialog box during color separation output to modify the spot color screening angle.
Conversion from spot color to four printing colors. When doing graphic design, many designers often use colors in some spot color libraries to define colors and perform coloring processing, and then convert them into CMYK printing four colors during color separation. At this time, you need to pay attention to three points: First, the spot color gamut is larger than the four-color printing gamut. During the conversion process, some spot colors cannot be fully fidelity and some color information will be lost; second, you must select " Convert spot color to four-color" option, otherwise it will cause output errors; third, do not think that the CMYK color numerical ratio displayed next to the spot color number allows you to reproduce the effect of the spot color with four-color printing inks with the same CMYK composition ( If you can, you don’t need spot colors). In fact, if you follow the same method, the colors you get will have a big difference in hue.
Trapping of spot colors. Since the spot color is different from the four-color printing (the four-color printing ink generates an intermediate color by overprinting each other, that is, the ink is transparent), when used, usually the overprinting of two spot colors will not generate an intermediate color. Intuitively speaking, that will Obtain a very dirty color effect (of course there are exceptions, such as intentionally using spot color overprinting in the design to produce the required third color produced by overlay mixing. This third color is full, thick and substantial, such as: spot color yellow The spot color red modulated by embossing, the two colors are overprinted to produce a stable deep red, often used as book covers, etc.), so to define spot colors, generally do not use the overprint method but use the blank ( Keepaway). In this way, when using spot colors, as long as there are other colors next to the spot color graphics, appropriate trapping processing should be considered to prevent the white edge problem from occurring (the methods of spot color trapping and related technical issues are more complicated, No further details will be given).
Color matching system for spot colors. When choosing a computer color matching system, first of all, you should be clear about which are spot color systems and which are CMYK four-color printing systems, so as to know whether the colors in the system you choose will have color conversion during color separation output and whether they will Color distortion occurs. For example: Commonly used color matching systems in graphics software include PANTONE, TRUMATCH, FOCOLTONE, TOYO ColorFinder, ANPA-COLOR, RIC Color Guide, etc. Among them, TRUMATCH, FOCOL TONE and ANPA COLORR are systems developed based on the four colors of printing, and others are all spot color systems (the PANTONE system covers a wider range of applications, including both printing colors and spot colors). This means that in spot color matching systems such as PANTONE spot color, TOYO Color Finder and RIC Color Guide, many of the colors have exceeded the four-color printing gamut and cannot be reproduced with four-color inks. The CMYK combination provided by the system Values ??are only approximate. So if you choose the spot color color to match the color in the system, and output it as a printing four-color separation; or refer to the corresponding CMYK combination values ????approximately displayed in the system for the spot color, and use these values ????to replace the printing four-color The original spot color will definitely lead to color distortion; secondly, it should be understood that when the spot color color matching system performs color separation processing, unless it is specially configured to convert the spot color into CMYK four-color output, otherwise, every used Spot colors are automatically separated into one color palette independently.
In the same way, after the colors in the printing four-color color matching system are used for coloring processing, the color separation output will be automatically applied to the four printing plates according to the CMYK ratio value of the color itself, without producing more color version. Furthermore, please note: in a bitmap environment, after the selected color (such as spot color) is used on the canvas, it will automatically be converted into the same color mode (such as CMYK four-color mode) as the data file to which the color is applied. . Therefore, in bitmap drawing software, spot colors must be deliberately added or specified (for example: when adding and defining spot colors in Photoshop, there are two situations: if the spot color is applied to the entire image as a tone , you need to convert the image to duotone mode and apply a spot color on one of the duotone plates; if you use a spot color for a specific area of ??the image, you must create a spot color channel); in a vector drawing environment, if When a spot color is selected or defined, the color will always exist as a spot color, unless the spot color attributes are specifically changed or converted into a process color (for example: a spot color added and defined in Iiiustrator, even if it is referenced to The color attributes of this spot color will not change if the data file using this spot color is opened in other Illustrator data files or with other vector software.)
Cost of spot color printing. Generally, spot color printing is usually used for printing with less than three colors. If more than four colors are needed, CMYK four-color printing is appropriate. Because CMYK four-color printing is basically based on dot overprinting, while spot color printing is basically solid printing. Although spot colors are usually only used in part of the image, when estimating, it is customary to charge twice the price of ordinary ink. To estimate; in addition, if there are already four printing colors on the same page, it is equivalent to one more color for printing. If the printing press does not have redundant printing units (such as a printing press with less than four colors or a four-color printing press ), it will take twice as long to print, and the cost will be higher.
Spot Color Specifies the dot correction that will be used when displaying spot color channels and duotones.
Seven, the former should be a producer who makes a certain IDEA into a multimedia product, but there are also designers who handle everything from the IDEA of the product to the completion of the entire work. It depends on the nature of their work. .
The latter focuses on the final effect of the work when it is printed.
For example, a colorful CG (computer illustration work) will have slightly different color perceptions on different monitors, and the choice of ink, paper and printing method when printing a book All will affect the final effect of the work. If the multimedia product producer is the artist who draws the illustration, then the pre-press production staff is the coordinator who adjusts the painting to the best state.