What is Color?
Color derives from the spectrum of light (distribution of light energy versus wavelength) interacting in your eye with the spectral sensitivities of your eye's light receptors. As such, color is the visual perceptual property corresponding in our eyes to the categories of predominately red, green and blue spectrums of light. Color categories and physical specifications of color are also associated with objects, materials, light sources etc. based on their physical properties such as light absorption, reflection, or emission spectra which determine our perceptions of their colors.

Color Models and Color Space
In order to understand color models you should first become familiar with the following acronyms:

A color model is an abstract mathematical model describing the way colors can be represented by numbers, typically as three or four values or color components. For example, the RGB Color Model works with 3 sets of numbers each ranging from 0 to 255 (as described below). When these color models ate associated with a precise description of how the components are to be interpreted (viewing conditions etc.) the resulting set of colors is referred to as the color space.

SignMaster Cut and Color
Reproducing color accurately is difficult and requires sophisticated programming techniques which is as much an art, as it is a science, and it's for this reason you need a RIP (Raster Image Processor) which implements these techniques to reproduce rich, vibrant and accurate colors from large format printers.

Working with Color Models in SignMaster Cut
SignMaster Cut uses several and well known color models to assist you in creating and reproducing colors easily and accurately. These include the CMY, CMYK, HSV, L*a*b* and RGB Color Models which are available throughout all SignMaster Cut's color mixers plus Greyscale in the Spot Color mixer, outlined as follows:

CMYK Color Model
The CMYK color model is a subtractive color model and is the minimum set of color channels used by all Large Format Printers. CMYK refers to the four inks used in color printing: cyan, magenta, yellow and black. The CMYK model works by partially or entirely masking colors on a lighter, usually white, background. The ink reduces the light that would otherwise be reflected. Such a model is called subtractive because inks “subtract” brightness from white.

In additive color models such as RGB, white is the “additive” combination of all primary colored lights, while black is the absence of light. In the CMYK model, it is the opposite - white is the natural color of the paper or other background, while black results from a full combination of colored inks.

Many Large Format Printers also use lighter variants of Cyan, Magenta and Black (Lc, Lm, Lb) to be able to print finer graduations of color especially for skin tones where the full color inks are too aggressive for these more subtle and gradual tones of color. These ink channels are used to their full advantage in the RIP process and you do not need to work with these channels at the designing stage.

L*a*b* Color Model
A Lab color model is a color-opponent space with dimension L for lightness and a and b for the color-opponent dimensions, based on nonlinearly compressed CIE XYZ color space coordinates. As such, where LAB is used in SignMaster Cut this is an abbreviation for the CIE 1976 (L*, a*, b*) color model, also referred to as CIELAB.

CIE L*a*b* (CIELAB) is the most complete color model specified by the International Commission on Illumination (Commission Internationale d'Eclairage, hence its CIE initials). It describes all the colors visible to the human eye and was created to serve as a device independent model to be used as a reference.

The three coordinates of CIELAB represent the lightness of the color (L* = 0 yields black and L* = 100 indicates diffuse white), its position between red/magenta and green (a*, negative values indicate green while positive values indicate magenta) and its position between yellow and blue (b*, negative values indicate blue and positive values indicate yellow). The asterisk (*) after L, a and b are part of the full name, since they represent L*, a* and b*, to distinguish them from Hunter's L, a and b which is a variant color model.

RGB Color Model
The RGB color model is an additive color model in which red, green, and blue light are added together in various ways to reproduce a broad array of colors. The name of the model comes from the initials of the three additive primary colors, red, green, and blue. In SignMaster Cut each channel in the RGB Color Model is represented by a value of 0 through 255 which sets how much of each of the red, green, and blue channels are included. If all channels are at zero the result is black, and conversely if all are set to 255, the result is pure (represented) white.

HSV Color Model
HSV is a cylindrical-coordinate representations of points in an RGB color model (as explained above), which rearrange the geometry of RGB in an attempt to be more perceptually relevant than the Cartesian representation. As such, HSV is a more intuitive and therefore easier to use Color Model than RGB.

HSV stands for hue, saturation, and value. In each cylinder, the angle around the central vertical axis corresponds to 'hue', the distance from the axis corresponds to 'saturation', and the distance along the axis corresponds to 'lightness', 'value' or 'brightness'. In SignMaster Cut’s color mixers adjusting or mixing a color using HSV is very easy using the provided sliders.

Working With Named Colors (Palettes)
The Color Library comes with many thousands of color swatches from leading Vinyl and Paint Manufacturer's. Each color swatch is in the Lab color space and can be adjusted by you and saved off as a new color palette if required.

Working with Spot Colors
SignMaster Cut comes with a dedicated Spot Color mixer allows you to set a Code and Name for any selected color (for an existing object) or any made up color by setting the individual values for each color channel. The Spot Color mixer is ideal for setting specific colors, usually spot or ink colors, however the information is saved with the document only.