CMYK (subtractive) CYMK is known as a subtractive colour space in which each subtractive primary is made up from each primary additive colour, for example when two subtractive primaries are mixed they make additive primaries, yellow and cyan mixed together make green. CYMK is the colour space used for printed images although they can be produced in a variety of ways the most common way in which images are printed is through the CYMK colour space. The process separates a full colour image into a separation of four primary colours, Cyan, Yellow, Magenta and Black each layer of colour is then separately printed on top of each other to create a final full colour image. When Cyan, Yellow and Magenta is printed in theory this created black however we still print a black over the top to create a rich black as without this doing this the black would appear more like muddy brown colour rather than a true black.
RGB (Additive) RGB is an additive colour space that is used to create colour on screen based devices, in which two additive primaries overlap to make a subtractive primary green and red overlap to make yellow. All three additive primaries overlap to make white light. Within CYMK the three subtractive primaries overlap to make black.
Monotone A monotone image is an image that has been created using different tones of a single colour to produce an image, any colour can be used with this process however it is more commonly used to produce greyscale images made from black ink.
Duotone Duotone is similar to a monotone however two colours are used to create the image which can add more depth to the image than that of single colour monotone. Commonly a black and a secondary colour would be used in a duotone. Using a second colour can enhance the appearance of an image that may more closely resemble a full colour image. A third colour can also be used with this process to create a tri-tone image which has the same effect but even more added detail and depth.
Spot Colours Images can also be produced using spot colours, spot colours are specific colours that are applied to specific areas of an image, often these colours are colours that can not be produced using the CYMK printing process. Spot colours are applied using another cylinder and are applied as a separate layer of colour. However spot colours can also be used to print with, as many spot colours as needed could be used to produce an images. Instead of using the process of CYMK a series of specific spot colours could be used to produce an image.
Pantone matching system is an internationally used system and series of colours which can be used to print specified colours. Each colour within the system has a specific reference code which you used to specify particular colours to a printer. The PMS system has a much varied variety of colour than the colour capable of being produced by the CYMK process. The PMS also has a range of specialist colours such as metallic and fluorescent colours. The PMS colours react different with different print processes and surfaces therefore the colours come in a range of formats such as colours for uncoated and coated stocks. The PMS colours can be specified using swatch booklets which are booklets that contain a swatch of each colour and its reference code, these booklet come in many versions such as Matt, Solid and process colours.
Hue is the reference to the unique characteristics of a particular colour which is used to help visually identify and specify a colour from another colour. The hue of a colour is formed by different wave lengths of light.
Saturation also referred to as the chroma of a colour is how pure the colour is and how it move towards or away from the colour grey.
Brightness The brightness of a particular colour is a reference to how light or dark the colour is, the brightness of a colour is changed by adding white to make the colour brighter and adding black to make the colour darker.
Colour Calibration When working digitally on a computer screen the RGB colour space is used by the monitor to produce colour, monitors can be colour calibrated so that the monitor more accurately represents the colour space that will used when printed. Most monitors work on sRGB which is the standard for RGB that is device independent which ensure all colour is shown the same though the monitor however when monitors are calibrated the colours produced are changed to better represent how colours will appear when printed.
DPI is the acronym for dots per inch and this is the measurement for the printed resolution of images. DPI is the measurement for how many colored dots per inch will make up an image, the higher the DPI the more defined the image or text will become however the industry standard DPI is 300.
PPI is the acronym for pixels per inch and is used to measure the pixel density of computer monitors and other screens, PPI is used to describe the resolution of an unprinted image when viewed in a digital format, or when images are taken with a camera of scanned into the computer. The standard PPI for an image is 72, however this is not suitable for printing as it will appear distorted when printed.
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[Mason, D. (2007) 'Materials, Process, Print: Creative Solutions for Graphic Design' London, Laurence King]