# Color TV Question

#### PNeil

Joined Oct 27, 2010
11
Hello there I already answer the question on my test and get it wrong, they gave me the right answer (which they never taught)

If one of the video output fails in a color TV, what are the symptoms?

a: No Video
b:Black and White reception will be tinted.
c:Color reception will be missing a color.
d: All of the above.
e: Both b and c.
f: None of the above.

I choose f because they never mention a word about tinted in the book and how can it be c?

The reason I say this is because on explaining how the color TV works...by mixing the 3 primary color to produce the required colors. If one gun fails this should cause not only 1 color missing but hundreds if not thousands. If you think about it, color is produce by mixing a certain percent of each color or I should say hitting the phosphor with the right amount of strength. I know If I have the 3 primary colors in a cup and one of the colors spilled I can still get a lot of colors by mixing...

They said the correct answer is e.

#### Georacer

Joined Nov 25, 2009
5,182
Number c means that a basic colour will be missing, making it impossible to mix successfully any other colour apart from the two basic left.

In a colour tv, black and white are made up from equal proportions of the three basic colours. If one is missing, the combination of the other two will dominate the image.

Joined Dec 26, 2010
2,148
Yes, it's got to be (e). Obviously there will be some kind of picture, ruling out (a) and (d).

The "tinted" answers have to be right. Wouldn't you agree that if you were to look at any normal picture through a really strong cyan, magenta, or yellow colour filter, you would see it appearing very strongly tinted* by the filter colour?

Well these filters have the effect of subtracting the red, green, or blue light respectively from the image, just as if a CRT gun had been turned off.

*Excepting colour pictures having such extreme colour casts to start with, but those would hardly be typical.

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#### PNeil

Joined Oct 27, 2010
11
I think the question was ask incorrectly. Its missing a basic color, not a color. Doesn't matter how you look at it, its not aaaaaa.... color.

Also, how am I to know what will happen to the black and white. They never explain how black and white was created in a color television. (That's future topic) I am just studying black and white at the moment. Why do they think I would know what will happen to the black and white.

My grade was 95 anyway because I got two incorrect (including this question).

I did choose loosing a color even thou I think it was not presented correctly. As far as the black and white being tinted. I was clueless.

#### Georacer

Joined Nov 25, 2009
5,182
If you ask for my opinion (that's how it seems at least), I think when we talk about a mission colour in the tv receptor, it goes without saying that we are talking about a basic one.
I find it also basic knowledge in our era, that a colour tv displays black and white through the combination of the three basic colours.
If you however say that you weren't taught that, then I have no reason to defy you.

#### JoeJester

Joined Apr 26, 2005
4,390
The basic colors were Red Green and Blue, in the NTSC scheme.

If you have a RGB output and a RGB input display, test it yourself. Pick a color and remove it. Transmitt a B&W image (old show on DVD) or a Color image (newer show on DVD) and see for yourself. If you don't have that, then strip back your monitor cable and snip one of the video wires.

You will have emperical evidence the answer, as given by your professor, is correct. And as a bonus, if you snipped a wire from your monitor cable, you get to practice your soldering technique.

Joined Dec 26, 2010
2,148
I think the question was ask incorrectly. Its missing a basic color, not a color. Doesn't matter how you look at it, its not aaaaaa.... color.

Also, how am I to know what will happen to the black and white. They never explain how black and white was created in a color television. (That's future topic) I am just studying black and white at the moment. Why do they think I would know what will happen to the black and white.

My grade was 95 anyway because I got two incorrect (including this question).

I did choose loosing a color even thou I think it was not presented correctly. As far as the black and white being tinted. I was clueless.
Unfortunately "they" are probably so used to thinking about a subject that they understand inside out that they might assume everyone knows such things. To be fair to them, some people in the general population might well know this, especially if they had covered relevant material on colour vision in school science courses.

At any rate, in the ordinary way of displaying the colour image, you would presumably know that white requires contributions from all three guns. The CRT has no other mechanism for producing white light, so all guns are also needed while displaying "black and white". With one gun not functioning, the "black and white" picture must therefore develop a strong colour cast.