Transparency may not seem particularly exciting. The GIF image format which allowed some pixels to show through the background was published over 30 years ago. Almost every graphic design application released in the last two decades has supported the creation of semi-transparent content. The novelty of these concepts is long gone.
With this article I’m hoping to show you that transparency in digital imaging is actually much more interesting than it seems – there is a lot of invisible depth and beauty in something that we often take for granted.
Good explanation about alpha compositing by Bartosz Ciechanowski.