Colour Space

There are 5 different colour spaces when dealing with images:

RGB (red green blue)

Greyscale

YUV (luminance and chrominance)

HSV (hue saturation value)

CMYK (cyan magenta yellow black)

RGB

RGB uses ‘additive colour’ to make new colours. It does this by adding light to the source which is being coloured and adjusting it and adding colour until the right shade is created. Red, green and blue colour values are stored differently. RGBA has an extra ‘alpha’ colour setting to change the transparance of an image.

CMYK

CMYK is made from Cyan, Magenta, Yellow and Black. This colour mode is used when the intent to print is involved. unlike RGB, CMYK adds ink to white until the desried colour is schieved. It is easier and simpler to use for printing because the setting deals with colour in the same way a printer would, by slowly adding ink to increase the density. This makes it more useful for printing because the RGB colours are more vidiv and bright, making them hard to make with inks.

Greyscale

Grayscale images give the best quality if the desired effect is for something that looks old. Greyscale images are only ever in different shades of grey that can be as light as white or as dark as black. Over 256 shades are used in one picture to give the best quality detail. An easy way of switching to this colour mode is to completely desrease the saturation of the image. any colour will be drained leaving only shades of grey.

YUV

YUV is used when dealing with images in a video. The Y stands for “luma” which is how bright the image is. The U and V provide a code which is converted into colour  through a signal when the video is played and are known as the chrominance components. It used the RGB colour mode to display images. the luma changes how light the images are and makes the colours paler but the light more intensified.

HSV

 HSV colours are represented in a cylinder. the central axis ranges from black at the bottom, shades of grey in the middle and white at the top. The colours around the axis represent the Hue, the distance from a colour to the axis shows the Saturation and how far along the axis the colour is represents it’s value. HSV is the colour space used to improve the simple colours in RGB to give an image more tones and highlights. This colour mode is most often used in digital graphics. The user can select a colour and then choose it’s hue and saturation from a separate menu.

~ by Fizwidget on November 29, 2007.