Usefulness of Layers

Nate_Houle · Jan 8, 2010

First off, this is my first post ever on this forum so excuse any photo forum faux pas in my post. Great site thus far btw.

On to my point...

I've been trying to "perfect" the art of post-processing but I think I missed an important part of the picture: layers. I keep hearing how valuable they are and what a big difference they make but I have failed to grasp their importance. Perhaps this deserved to be in the beginners forum but any help and/or explanation would be great.

Thanks in advance.

Big Mike · Jan 8, 2010

The use of Layers is probably the most useful aspect of a program like Photoshop.

Firstly, layers allow you some freedom, or saftey (depending on how you look at it). For example, the first step in editing a photo, for many people, is to make a duplicate layer. That way, you always have the original image as your 'background' layer....and any changes or edits you make, can easily be undone or erased because the original pixels are still there.

Another benefit is that you can easily separate your different edits. For example, you can create a new layer for adjusting the 'levels', then create another layer for adjusting the 'color balance', then another layer for some text. With these separate layers, you can go back and make further adjustments at any time. For example, let's say you adjust the levels to make the image darker, then go on to make other adjustments...but then you think the image is too dark. You can just go back to the levels layer and change those settings. This same philosophy applies to just about every thing you can do in a program like Photoshop.

Another benefit is selective editing. For example, if you just want to edit/change a part of the image, you can place that part onto a different layer. The 'best' way to do something like this, is to use 'Layer Mask'. A layer mask is something you can use to cover up parts of a layer. For example, if you want to create a selective color image (where some parts are black & white and some parts are color), you would create a duplicate layer and convert that layer to B&W. Then you just use a layer mask to cover parts of the top layer, allowing the color layer below, to show through.

If it helps, imagine the layers like those old animation cells. (drawings on clear cellophane sheets). Each layer has something on it and it covers the layers below, but if parts of a layer are clear, the the layers below with show through.

J.Kendall · Jan 8, 2010

Couldn't have put it any better myself Mike.

anel · Jan 8, 2010

i tried to explain the importance of layers to a friend that just installed photoshop and it's way harder than someone could think, but to make it easy do this..

open your image, then make a new layer and paint it black. take the eraser and smudge over the black and your lower layer is revealed. so that's the first step into layers.

second, delete the black filled layer and just ctrl+ J to copy your image layer then try various blending modes (normal, soft light, hard light) to see what effect it has..

tons of stuff you can do, these are just the basics.. you can let's say if you don't want to mask yet.. copy your image layer, sharpen it and then erase the parts where you didn't want to sharpen, there is a non-sharpened image still below your sharpened one

ooh, well mike beat me to it

Big Mike · Jan 8, 2010

I forgot to mention that you can adjust the 'opacity' of layers. Which means that you can fine tune any edit/effect that you put on a separate layer. For example, when retouching the wrinkles in a portrait, I will typically use a duplicate layer and erase (clone/heal) all the wrinkles off of someone's face. The problem is that it probably won't look realistic...or at least it won't look natural to anyone who knows that person. So the trick is to turn down the opacity of that layer, allows some of the wrinkles from the layer below, to show though.

The same idea applies to everything. You can create a new layer that is a solid blue color...covering your whole image. Now as you back down the opacity of that blue layer, the photo below starts to show through. As you dial it down, the blue gets less and less visible. At some point, it may start to look like it was shot under moon light. (guess how they shoot a lot of those night scenes in movies).

Nate_Houle · Jan 8, 2010

Ok I think I've got it. I'm sure there's more but I'll figure it out I'm sure. Thanks for the help!

burstintoflame81 · Jan 8, 2010

The biggest thing with layers other than them allowing you to non-destructively edit, is the style ( multiply, overlay, screen etc. ) It takes time getting used to what they all do, ( I am still learning ) but they all have their uses. It kinda goes along with the opacity settings as well. The other part is the masks. It makes it easier to apply settings to specific areas of a photo and then re-adjust those settings easily as you progress through the editing. There are many books that focus mainly on Layers. I got a few from my local library. I would start there. Even if you don't get everything, atleast some of it will sink in and you will start to form a general understanding of the layers. Its daunting though.

Garbz · Jan 9, 2010

The important part is that you can selectively adjust many aspects of the adjustment you make. You're using the clone tool but you find out AFTER that it's not transparent enough, well it's on a layer so you can adjust the layer.
Want that curves adjusted on a gradient mask rather than the whole images, well you can if it's on a layer, and you can change that mask whenever you see fit.
Want the changed layer to apply to only the pixels that are lighter than the underlying image, then you can adjust the blending method.
Want the change to apply only to pixels with values below 64, then you can modify the blending properties.

The layers tool is a fundamental concept to use with your edits that adds infinite possibilities and plenty of changes to anything you can do, and best of all it's like a selective undo if you screw something up.