what's the layer application in digital photography?

[vafa]

I noticed the “layer” jargon in my camera’s software as well as in some expert’s posts.
I do not know the layer’s function and its applications in digital photography. Is there any one to help me?
Vafa

[Roger_Cavanagh]

Vafa,

"Layer" usually refers to a digital file used by an editing program such as Photoshop. Typically, the original image (say, from your camera) is the background layer. Rather than edit the original picture, you can add a layer. You can use layers to change contrast, brightness, colour, saturation... a whole bunch of things. When the layer is turned on, you see the image with the effect applied, but the original image underneath the layer is actually untouched.

Other advantages of layers are that you can easily change the settings, for example, change the contrast setting and you can reduce the effect by changing the opacity, so more of the original shows through.

You can have lots of layers in a document and there are many other things that can be done that would take too long to explain.

Regards,

[Scottes]

Generally when describing layers in Photoshop I suggest that people think of a piece of clear plastic layed over the original photo. You can draw on the clear plastic and never touch the original. You could put on a piece of green plastic to tint the image green. And so on.

But layers are much more powerful than that. You can do many many thing on a layer which modify the original without ever changing the original - many of these things don't fit the "clear plastic" analogy I use to initially describe layers, but the analogy is a good starting point.