What's the Difference Between RGB and CMYK Color Processes?
CMYK is made up of four colors: Cyan, Magenta, Yellow, and Black. In full-color process printing, CMYK is the standard method for offset printing. In the printing process, CMYK colors are measured by their subtractive/ reflective values; when the colored ink is applied to paper, the surface of the paper reflects some color and the non-reflective (that is, absorbent) color is seen. CMYK colors are obtained by mixing the strengths of each color to produce a new color. The colors are mixed in percentages: 0% represents no color, whereas 100% represents a maximum use of color. Cyan, Magenta, and Yellow combine to create the color, while Black is used to change the shade of the color.
RGB color scheme consists of three colors: Red, Green and Blue. These three colors are projections of light that can be overlapped in millions of color-strengths and combinations to create on-screen colors and images. RGB colors are associated with television screens and computer monitors, but RGB is not used in offset printing.
The RGB color process and the CMYK color process work in opposite ways. An RGB color scheme forms color through an additive process; to obtain white, all 3 colors are added together, and to obtain black, all 3 colors are removed. In contrast, the CMYK printing process obtains white by omitting all color, and obtains black by using all four colors. When using a professional offset printer like those found on this website, it is imperative that all files are provided in CMYK format.
It is important to note that a color printed on a professional press will never exactly match what you see on your monitor (remember, computer monitors are RGB and printing presses are CMYK). Colors vary from monitor to monitor, and different printers produce different color results. All these variables affect the printed outcome.
RGB color scheme consists of three colors: Red, Green and Blue. These three colors are projections of light that can be overlapped in millions of color-strengths and combinations to create on-screen colors and images. RGB colors are associated with television screens and computer monitors, but RGB is not used in offset printing.
The RGB color process and the CMYK color process work in opposite ways. An RGB color scheme forms color through an additive process; to obtain white, all 3 colors are added together, and to obtain black, all 3 colors are removed. In contrast, the CMYK printing process obtains white by omitting all color, and obtains black by using all four colors. When using a professional offset printer like those found on this website, it is imperative that all files are provided in CMYK format.
It is important to note that a color printed on a professional press will never exactly match what you see on your monitor (remember, computer monitors are RGB and printing presses are CMYK). Colors vary from monitor to monitor, and different printers produce different color results. All these variables affect the printed outcome.
Common Printing TermsBLEED Ink coverage that extends to the edge of the finished (trimmed) piece. Designs without margins (full bleed) require additional space around the image to allow for trimming and is usually more expensive than designs with a 1/4" or 3/8" inside margin.
CMYK The acronym for the four basic ink colors used in "process" color printing: Cyan, Magenta, Yellow and Black. FINISHED SIZE The dimensions of a printed piece after trimming. GRAY SCALE The tonal range from a very light gray (1% dot) up to solid black (100% dot) in increments of 1%. PMS COLORS PMS stands for Pantone Matching System and was developed for color identification. The system assists designers and printers in the communication process for color specification on printing orders. Each PMS color has a unique number and formula for ink mixing. PMS colors are also referred to as "spot" colors. PROCESS COLOR The four basic colors of ink used in process color printing are cyan, magenta, yellow and black. These ink colors are transparent and "process" with each other when overprinted in predetermined amounts. i.e. when cyan overprints yellow, it produces green, when yellow overprints magenta, it produces orange. Controlled screen tint combinations of the four basic colors allow the full spectrum of colors to be produced on a printing press. Colors are semi-opaque and will be affected by the stock color. On clear stocks a base of white (fifth color) should be used to block light ands to keep colors true. |  http://www.dpbolvw.net/click-3503764-10551215
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printing articles
| PROCESS COLOR SEPARATIONS Color separation refers to the breaking down of any full-color image into the four basic ink colors used in printing. The making of a color separation involves the use of a laser light scanner which, through the use of four color filtering systems, can "read" and record the amounts of cyan, magenta, yellow and black that is present in any particular area of a color original. The recording of this data is converted into digital form and saved to a computer for further processing and placement into page layout programs.
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RESOLUTION The quantification of output quality designated in dots per inch (dpi) when applied to paper output and in lines per inch when applied to film output. Laser printers commonly hold resolutions of 300, 600, 800 and 1200 dpi. Film output units (imagesetters) have variable resolution output; but are most commonly specified based on the surface type of papers to be printed. Screenprinting can hold a resolution from 55 to 70 line screen. Newsprint can hold a resolution from 85 to 100 line screen. Uncoated papers typically use 120, 133 or 150 line screens. Coated papers can hold resolutions of 133, 150, 175 and even 200+ line screens.
TRAPPING Trapping is the precise relationship between two ink colors when they butt together on a printed sheet. If no trap is added, a white gap may appear between colors. If too much trap is added, a dark line will appear where the colors overlap.
TRAPPING Trapping is the precise relationship between two ink colors when they butt together on a printed sheet. If no trap is added, a white gap may appear between colors. If too much trap is added, a dark line will appear where the colors overlap.
Differences Between Common Printing Methods
Offset Printing is the process whereby a printing plate first transfers its inked image areas onto a rubber blanket mounted on a cylinder in the printing press and then the rubber blanket transfers (or offsets) the inked image onto the paper as it passes through the press. An image setter is used to make the film that will be used to generate the metal printing plate.
The term offset is often used interchangeably with lithography, which is the printing process consisting of chemically treated metal plates that accept oil but reject water. After the plate is placed on the printing press, ink is applied to the surface of the plate and stays in the image areas. A minuscule amount of a water solution is applied to and stays in the non-image areas of the plate defining where the ink is positioned to an accuracy of 1/1000 of an inch. Ink sticks to the plate where needed, and then the ink pattern is transferred to the rubber blanket.
Offset lithography printing produces high quality printing and less deformation because the rubber blanket adapts itself to the texture of the paper. This printing method also preserves the plates from damage, because they don’t come in direct contact with the paper surface. Offset printing is ideal for high volume printing jobs that require a good quality.
Offset presses are primarily of two types. Sheet-fed Offset Printing Press means the printing is carried out on single sheets of paper as they are fed to the press one at a time. Web-fed Offset Printing Press means the printing is carried out on a single, continuous sheet of paper fed from a large roll. The sheet is then cut into individual sheets of desired sizes.
The term offset is often used interchangeably with lithography, which is the printing process consisting of chemically treated metal plates that accept oil but reject water. After the plate is placed on the printing press, ink is applied to the surface of the plate and stays in the image areas. A minuscule amount of a water solution is applied to and stays in the non-image areas of the plate defining where the ink is positioned to an accuracy of 1/1000 of an inch. Ink sticks to the plate where needed, and then the ink pattern is transferred to the rubber blanket.
Offset lithography printing produces high quality printing and less deformation because the rubber blanket adapts itself to the texture of the paper. This printing method also preserves the plates from damage, because they don’t come in direct contact with the paper surface. Offset printing is ideal for high volume printing jobs that require a good quality.
Offset presses are primarily of two types. Sheet-fed Offset Printing Press means the printing is carried out on single sheets of paper as they are fed to the press one at a time. Web-fed Offset Printing Press means the printing is carried out on a single, continuous sheet of paper fed from a large roll. The sheet is then cut into individual sheets of desired sizes.
Direct-to-Plate Printing is similar to the offset method, except that the metal plates are made directly from a computer file rather than from film, which decreases costs. The disadvantage is that, since there is no film involved, there’s no possibility to make a color correct proof before making the plate. Instead, you can get a digital color proof, which is less costly but also less accurate than a film color proof. The elimination of the film-creation step effectively reduces costs, so direct-to-plate printing is a recommended choice for projects that don’t require an exact color match.
Digital Printing is a fancy form of color photocopying. In this method, the image is sent directly to the printer: no film, no plates. For low-quantity printings, this is the most cost-effective solution, although for bigger jobs, offset or direct-to-plate should be used. Although substantially cheaper, digital printing can only work with CMYK colors (i.e. no Pantone or spot colors), and thus it may not be ideal for certain projects. |
In addition to quality, the quantity you will need of your finished print job is probably the deciding factor as to which printing method to use. It’s not uncommon to find that a supposedly cheaper method is indeed more expensive for larger jobs.
