explain Layers ?

Hello

Does anyone have any useful links to somewhere that explains the differences between layers, layers via copy, layer from background etc etc.

Its confusing me.

Cheers

A layer is a layer, except that the background layer is not "layer-editable" unless you unlock it by Alt-Double-Clicking on the work Background in the layer toolbar.

An adjustment layer is a whole other beast....

An adjustment layer is a layer which contains only the info needed to modify the layers beneath it. That is, (as an example) you can create an adjustment layer that increases brightness by 15%. Any layer(s) beneath this adjustment layer will gets it's brightness APPARENTLY increased by 15%. Remove the adjutsment layer and the under-layer image goes back to normal brightness. Put a new image above this under-layer - but still below the adjutsment layer - and THAT layer gets an apparent 15% brightness boost.

You can Tweak the adjustment layer to 17% brightness AND 5% saturation... whatver. The adjustment layer info is never applied to the under-layers until you flatten. Until then, every layer is untouched, unmodified. Yet the adjustment layer lets you see what it will look like once you flatten.

I'm not so sure that helped... It probably made things worse, right? If so...

Layers via Copy, which is Ctrl-J, is the same as copying your selection, creating a new layer, and pasting on to it.

Layer from background makes the Background an editable Layer (that Alt-Double Click that Scottes mentioned)

Layers Explained...
http://www.photoshopca​fe.com/tutorials/layer​s/Layers.htm

https://photography-on-the.net/forum/showthre​ad.php?t=93697

You can copy the contents of a layer (or selection) by using CTRL-C (or right-click or menus). This will copy the contents of the layer.
Then you can press CTRL-V and a new layer will be created with that selection (layer via copy).
You can press CTRL+Shift+C when you copy to copy the merged appearance of the layer which would include any visible adjustments that have been made.

You can have as many layers as you want... some with content that will overwrite the layers that are below... or you can partially show the layer if you drop the opacity. If the opacity isn't 100%, the layers below will start peeking through.

You can apply masks to a layer which will either hide or show the effect. It's much like putting painter's tape up before you paint. You cover the windows, lights, trim on a car before you paint (which is a mask) then you paint over everything.
If you think of a mask this way, anything that is in black is basically covered and the effect won't show.

If you have a background layer that's solid red... then you add a layer a layer on top that's solid blue... and you add a layer mask to the blue layer and paint a big black dot in the middle... you'll see the red come through.

Adjustment layers are a little different as Scottes mentions. An adjustment layer will affect the appearance of a layer (or combination of layers) by changing the hue/saturation/levels/​colour/etc. You can also mask these layers so they only affect a portion of the image, or link them to the layer below them by alt-clicking the line that separates 2 layers.

Do you have any specific questions?

Technically, that's the long way. Ctrl-J does all of that in one click and Layer Via Copy means that all you need to have done is made the selection (ie, whatever is masked). Hitting Ctrl J is the same as Ctrl-C, New Layer, Ctrl V.

Try it, it's great.

I know, I use CTRL+J all the time. Just trying to explain it in "common" terms.

That and CTRL+Shift+C, CTRL+Shift+ALT+N, CTRL+Shift+ALT+E, CTRL+ALT+~ are in my normal shortcut arsenal.