Why transparency is shown as a chessboard pattern?

Question

A suitable raster graphics editor shows transparency by a special pattern, e.g. a chessboard pattern.

I wonder why complete transparency is shown as chessboard pattern? Is it chosen deliberately by people, or just a natural appearance of transparency under some circumstances?
How shall one distinguish an image which is actually a chessboard from an image with complete transparency?

Thanks!

It makes it easy to recognize, with transparency also shown via pink, since if transparency was shown as transparent, it would be difficult to recognize — JW0914, Jan 23 '24 at 13:21

score 7 · Answer 1 · edited Jan 23 '24 at 11:20

7

It's tradition.
By inspecting the pixel values or superimposing the image over a background, or by zooming in and observing that the chequerboard spacing is unaffected.

edited Jan 23 '24 at 11:20

MarianD

answered Jul 24 '12 at 11:45

RedGrittyBrick

Why is it a tradition? – Tim Jul 24 '12 at 11:48
4

@Tim: for the same reasons that the Utah Teapot is a tradition. – RedGrittyBrick Jul 24 '12 at 11:59
3

You can. Viewers with zoom functionality (e.g. mostly all) will not zoom into the chessboard pattern, while enlarging the image. – Jonas Schäfer Jul 24 '12 at 12:11
@JonasWielicki: thanks, answer updated accordingly. – RedGrittyBrick Jul 24 '12 at 12:17

score 0 · Answer 2 · answered Jan 23 '24 at 12:14

If an application would show transparency as a specific colour, you would never know whether an area is transparant or just happens to have that colour. If the application would show the background through the image, you still wouldn't know whether the image happened to contain the background colour. Therefore it has to be a pattern, not a solid colour. A chessboard pattern happens to be less common in images than, for instance, diagonal shading.
As @RedGrittyBrick said, zoom in or out to check. The chessboard patterns will remain constant.

2 Answers2