Computer imaging concepts 3.

Color management of graphics.

Color management in the use of
    -input devices such as scanners, digital cameras and digital x-rays
    -output devices such as  printers and monitors.  

Know the resolution, size and bit depth of the image coming from the input device
     - dental digital x-rays have an 8-16 bit depth --gray scale.  
     -through an intra-oral camera usually as 24 bit RGB image.
     -through a scanner as a variety of settings as determined when scanning.
                -Best to set physical properties initially.
                -It can also be edited, after acquired, within a graphics program.

For output to a printer use the 24 bit setting to print to a RGB (red, green, blue) or a CMYK (32 bit)  printer.

 

You can convert a 24 bit color image to grayscale (8 bit, 256 shades) and decrease the file size. You may also convert a 24 bit image to a smaller file size, 256 colors--8 bit image. This results in a loss of some color intensity.    For such conversions CorelPaint™ and Photoshop™   can be used.
This example is taken from CorelPaint™ and shows the conversion of a 24 bit image to 8 bit, 256 color image.  If it is done without a process called dithering, poorer results are obtained.   Dithering is created by averaging the depth of adjacent  pixels when pixels (resolution) are  up-scaled or down-scaled to create a homogeneous appearance of colors or shades of gray. Image Dithering is a method of enhancing the appearance of photographic images when the original color palette is changed.
With dithering that is ordered or using error diffusion, a better result is observed. (Ref: Mohler JL, Grpahics, Animation and Multimedia, pp 103-142, Sams.net Publishing, Indianapolis, 1997.)

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