Glossary of Printing Terms
A bitmap image is composed of a collection of pixels. Photos are bitmap images, as are almost all images found on websites. When working with bitmap images, the most important factors are resolution and color mode. Common formats are .jpeg or .jpg, .tif or .tiff, .png, .gif, or .bmap. Photoshop native files, which use the extension .psd, are always bitmap images. Some files with .eps at the end of the name are bitmap images, while others are vector images..
In a bleed, the image goes all the way to the edge of the page. To achieve this result, it must be printed on a larger page. The printed area will extend beyond the desired edge of the page, allowing for variance in trimming and preventing ink buildup along the edge of the paper. If your image should bleed, please be sure the image extends .125” beyond the edge. Be aware that this often increases the cost of a job.
A booklet is a collection of pages which is held together without the use of a separate binder. The most common binding methods are saddle stitching, perfect binding, and stapling. Other options, such as plastic comb binding, spiral binding, plastic spiral binding, and wire binding, are available.
See Cover weight.
See also Process Color. It is also a color mode, where the color is specified in terms of the percentages of cyan, magenta, yellow, and black inks.
When it is made, paper is quite porous. Some paper has a layer of clay or other material applied to its surface after its formation. This provides a smoother and generally brighter paper. Though the most often used coated papers are glossy, other types are available, including dull, matte, semigloss, or satin. Though coated paper provides an excellent surface for printing, it usually costs more and may need to be varnished.
A color mode is a method of specifying color in a computer-generated image. Although many different color modes are available, CMYK and RGB are the most common. Since each color mode has a specific range of colors which can be produced, it is very important to use CMYK when creating images for four color process printing
Cover weight refers to heavier or thicker papers, often called cardstock. Cover weight can be as thin as an index card or much heavier, nearly as thick as cardboard.
Four color process
Four color process is a type of process color printing which uses four inks (cyan, magenta, yellow, and black). It is the most common type, though the color range is more limited than those using more ink colors.
See Four color process; also known as CMYK or process color.
Pantone, Inc. is an international corporation which has established standards for color matching. Besides the Pantone Matching System for printing, they have color systems for plastics, home decor, and fashion.
Pantone Matching System
The Pantone Matching System is Pantone’s system of specifying color for the print industry. Every color is identified by a Pantone or PMS number. This number allows any printer to match the colors out of the Pantone books. For printing in spot color, the correct books are the Pantone Formula Guides, either coated, uncoated, or matte, or the Metallic Formula Guide. The number is three or four digits, followed by a C, U, or M. For process-color printing, you may specify colors from the Pantone Color Bridge, which uses the same three or four digit numbers followed by “PC.” There is an additional system for printing, the Pantone Four-Color Process Guides; they use a special numbering system and are not part of the Pantone Matching System. For more information on these numbers, Pantone has an in-depth explanation at their website.
Perfect binding is a method for binding booklets. It features a wraparound cover; the inside of the spine is glued to the edges of the pages. Paperback books and many magazines use perfect binding.
See Pantone Matching System
Process color printing is a technique where a small number of transparent inks are layered in different ways to produce a wide range of colors. The most common process color system is four color process, using cyan, magenta, yellow, and black inks. Other systems exist which use six or seven colors (or more).
Resolution is the number of pixels or dots per unit of measurement; in the United States, it is measured in dots per inch (dpi) or pixels per inch (ppi). Resolution is one of the most important factors when working with bitmap images such as photos. Images for web pages are generally 72 dpi; for printing, good results usually require 300 dpi as a minimum.
RGB is the most common color mode used for images to be displayed on a monitor or television screen. It defines color in terms of red, green, and blue light. Some colors can be produced with RGB which cannot be matched in the CMYK color system. When this occurs, the software converts the color to its best approximation in the CMYK color mode, sometimes with undesirable or disappointing results. For this reason, it is very important that all images for printing use CMYK color.
Saddle stitching involves nesting folded pages inside each other and stapling through the spine. It is one of the most common binding methods for booklets, and is often seen with wall or pocket calendars and smaller, thinner magazines.
Spot color, in contrast with four color process, uses an ink mixed according to a formula. This ink is placed directly on the printing press and produces an exact color. If your project uses a limited color palette, spot color printing may be considerably cheaper than process color printing. It also allows for ink colors which cannot be reproduced with cyan, magenta, yellow, and black inks, including metallics, fluorescents, bright colors, and very light pastels.
Stock is the paper used for printing. Paper is usually divided into two broad categories: cover and text.
Text weight is a range of paper thicknesses, light enough to be used as the inside pages of books and booklets. It is lighter than cover weight.
Uncoated paper has not had any sort of coating applied to its surface after its formation. It is more absorbent than coated paper, so images are not as sharp or as bright. However, many uncoated papers are much cheaper. Cotton content papers (such as those used most commonly for letterhead) are uncoated.
Unlike bitmap images, vector images can be freely resized. Instead of defining an image in terms of dots, they tell the output device how to draw the shape. In this respect, vector images behave like fonts. Most vector images will have a file extension like .eps, .ai (Adobe Illustrator) or .fh* (Macromedia FreeHand). However, some files with the .eps file extension are vector images, while others are bitmap.
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