Grass Valley TTV 1657D - Manuel (Page 138)

138 Chapter 2 - Camera
Camera operation
B1657D902C
Septembre 2000
THOMSON TTV 1657D
User manual
2.2.3.2 - White balance
White balance is an automatic adjustment of the red and blue channel gains.
2.2.3.2.1 - Preset and balance memories
The camera has two memories to store the white balance corrections: memory "A" and
memory "B". The memory used is selected with the "A-B-PRST" selector switch on the
side of the camera.
On "PRST", there is no gain correction made by the balance. The gains then take on the
maintenance values giving equal R, G and B levels for a white illuminated with a colour
temperature of 3100°K or 5600°K. This position can be used:
• during maintenance, when adjusting the camera video chain,
• when there is no white reference available,
• if the light intensity is insufficient to perform automatic white balancing.
To select the preset 3100°K or 5600°K position:
• set the selector switch to "PRST",
• the current PRESET type, 3100°K or 5600°K, is then displayed in the viewfinder,
• using the "+" or "-" keys on the front of the camera, select the desired preset value.
The white balance can be started by the user or be performed permanently (refer to
2.2.3.2.3 - "Permanent automatic balance" paragraph).