Memory White Balance: In this mode of operation, the camera is pointed at a white object,
and the auto white button is pressed. The camera then automatically adjusts the red and
blue gains to produce white. This method is normally used for white balance, due to the
fact, that it also takes into account any effect the color temperature of the light may have on
the object being shot. Depending on the camera, this mode of operation has a large range of
color balance, and can handle light with color temperatures from approximately 2000 to
5800 degrees Kelvin.
Auto Tracking White: In this mode of operation, the camera attempts to make the brightest
object in the picture white. The red and blue gain are constantly and automatically adjusted
by the camera to account for differences in the color temperature of the light. This mode is
useful for long shots, and when the camera must shoot between different color temperatures
of light, without being white balanced. There is a drawback to this mode, in that it will at-
tempt to make the brightest object in the scene white. Should the scene not contain any
white object, but rather a light colored object, the camera will make this white. This will
cause all of the color reproduction of the camera to be incorrect.
For microscope applications, it is recommended that the memory mode of white balance be used. The
camera should be white balanced under the illumination level that will be used for the slide. The slide
should be removed, leaving a pure path of light to the camera. The camera would then be white bal-
anced, by pressing the auto white button. The slide can then be inserted in the path, and the colors
should then be correct. If the light intensity is changed, the camera may need to be white balanced
again, because normally the color temperature of the light will change with its intensity.