Having a single black pixel glaring at you when viewing certain background colors can be a bit frustrating and puzzling at the same time. Is it just stuck or is it dead? Today’s SuperUser Q&A post has the answer to a curious reader’s question.

Today’s Question & Answer session comes to us courtesy of SuperUser—a subdivision of Stack Exchange, a community-driven grouping of Q&A web sites.

Photo courtesy of Daniel Mogford (Flickr).

The Question

SuperUser reader Mirkan wants to know if a black pixel seen only when viewing a blue background is stuck or dead:

I have a pixel on my LCD monitor that appears black only when viewing a blue background, otherwise, it works fine with regard to all other colors.

Is this pixel stuck or dead?

Is this a case of a stuck pixel or a dead one?

The Answer

SuperUser contributor Tetsujin has the answer for us:

Dead. Stuck is ON, dead is OFF. Pixels are created from sub-pixels of primary colors, typically red, green, and blue:

The reason the dead spot is visible only when blue is displayed is because it is a blue sub-pixel that is dead. When the background is blue, that is the only color on and it stands out. When the background is another color, the other sub-pixels reproduce it or it is still bright and absent blue, which is less noticeable.

For example, you can see yellow because it is created from red plus green. A white pixel with a dead blue sub-pixel will produce yellow, which is not very noticeable in a bright spot that small.

Have something to add to the explanation? Sound off in the comments. Want to read more answers from other tech-savvy Stack Exchange users? Check out the full discussion thread here.

Akemi Iwaya
Akemi Iwaya has been part of the How-To Geek/LifeSavvy Media team since 2009. She has previously written under the pen name "Asian Angel" and was a Lifehacker intern before joining How-To Geek/LifeSavvy Media. She has been quoted as an authoritative source by ZDNet Worldwide.
Read Full Bio »