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SOOOOO....HOW DID BRIGHTNESS & CONTRAST GET CALLED THAT?

C

ChrisCoaster

Jan 1, 1970
0
Here's one plausible theory: Over time, black level and white level
acquired their nomenclature because of the effect adjusting them had
on viewers' pictures. IE: "Hon, could you make the picture a little
*brighter*?"

To me, they don't. Turning up the brightness knob only washes out the
image for me, but it isn't any brighter! Contrast, otoh, definitely
impacts how "bright"(vivid) a b&w or color TV image is.

Any other theories??

-CC
 
C

Charles Schuler

Jan 1, 1970
0
ChrisCoaster said:
Here's one plausible theory: Over time, black level and white level
acquired their nomenclature because of the effect adjusting them had
on viewers' pictures. IE: "Hon, could you make the picture a little
*brighter*?"

To me, they don't. Turning up the brightness knob only washes out the
image for me, but it isn't any brighter! Contrast, otoh, definitely
impacts how "bright"(vivid) a b&w or color TV image is.

Any other theories??

Contrast is controlled by the amplitude of the video signal applied to the
CRT, thus it is a gain control like a volume control in a radio. Brightness
is the dc bias applied and so controls the average beam current. Some sets
"interlock" the two controls so as to automatically keep the two in better
balance.
 
F

Franc Zabkar

Jan 1, 1970
0
Here's one plausible theory: Over time, black level and white level
acquired their nomenclature because of the effect adjusting them had
on viewers' pictures. IE: "Hon, could you make the picture a little
*brighter*?"

To me, they don't. Turning up the brightness knob only washes out the
image for me, but it isn't any brighter! Contrast, otoh, definitely
impacts how "bright"(vivid) a b&w or color TV image is.

Any other theories??

The "contrast" knob adjusts the gain of the video amps. As such it
affects the contrast between the light and dark parts of the image.
The "brightness" adjustment affects the brightness of the overall
image by varying the voltage on the G2 grid in the electron gun. This
in turn controls the number of electrons that hit the CRT face. Well
that's my understanding anyway.


- Franc Zabkar
 
F

Franc Zabkar

Jan 1, 1970
0
The "contrast" knob adjusts the gain of the video amps. As such it
affects the contrast between the light and dark parts of the image.
The "brightness" adjustment affects the brightness of the overall
image by varying the voltage on the G2 grid in the electron gun. This

Oops, that should be "G1".
in turn controls the number of electrons that hit the CRT face. Well
that's my understanding anyway.


- Franc Zabkar
 
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