Layer Masks Tutorial Author - NikonErik (http://forums.biorust.com/members/nikonerik.html)

Layer masks were very confusing to me the first time I tried to use them, but I persevered, and now they are one of the techniques I use most often to control where my effects are applied, and how layers interact.

For this tutorial, I will use Adobe Photoshop CS2 on a PC. This tutorial will very likely work just as well on a Mac system, although your mileage may very with older versions of Photoshop, depending on their feature sets. 

I will be using the stock image below. This is a Gibson Les Paul that I sold to buy my D70s camera. Trust me, I'm a much better photographer than musician! Feel free to copy it so that you can follow along, or use a comparable image of your own.

Step 1: Open your base image in Photoshop and make sure that you have the Layers window open. If its nowhere to be seen, you can open it by clicking on Window > Layers in the main menu.  In the layers window you'll see a tiny version of your image accompanied by its name,  'background'. Somewhere next to the word 'background', right-click with your mouse and select Duplicate Layer from the pop-up menu that appears. You can rename the new layer if desired (a good habit). Click OK.   Notice that the new layer is highlighted in the layers window? That's the activated one. You can click on any layer to activate it. Only the activated layer will change when you apply effects and modifications.

Step 2: Select Filter > Blur > Gaussian Blur from the main menu, enter 3px in the Radius box, and click OK.

The image looks ruined... but not for long! We will now remove the blur from the Les Paul body by painting a mask that keeps the blur away from the guitar body.

Step 3: Click on the Add Layer Mask icon at the bottom of the layer window. It's the one that looks like a piece of paper with a hole in the middle of it. You'll notice a white box that appears next to the layer picture in the window. That is now the active portion of the layer. Click on the little picture next to it and click back on the other thumbnail. You'll see what I mean. If a layer mask is active, all of your painting tools work a little differently in that they will only paint black or white. This may seem like something you don't want, but you'll see the magic in a moment! I generally only use the brush tool to paint the layer mask, but the bucket, gradient, smudge tools, etc, will work too, but with less fine control.

Step 4: Before we continue, lets take an inventory. Your background layer is nice and sharp. Your top layer blurry. You are ready to remove the blur from the guitar body, but leaving the furry case and the other background elements alone. You do this by painting black over the guitar body in the layer mask. Black became the default color when you created the layer mask, so all you have to do is select the brush size and softness that you are comfortable working with, and paint on the layer mask.

Take a look at the image below - The circular thing in the middle of the guitar is my brush. You can see I was painting with 100% white when I took this screenshot.-

So paint away! When I got to the neck of the guitar I changed the opacity of the brush to 25% - You can find that setting at the top of the Photoshop window. This way I carefully controlled the look of how the blur fades-in as you look down the neck of the Les Paul. What's cool about using the opacity like this is that you can keep painting and the "paint" builds, getting darker... and the darker it becomes, the more it blocks the blur effect!

If you make any mistakes you can always Edit > Undo or, better yet, clean up with white or an opposite opacity.

Step 5: At this point save your project .psd with an appropriate name, such as 'Les Paul v1' (as in "version 1"). Once you've saved it, right-click the background layer in the layer window and select Flatten Image. Right click it again, and select Duplicate Layer.

For the remainder of this tutorial, we will create a B&W layer above the color layer in the background and, just like before, we'll use a mask to reveal the color body of the guitar only.

Step 6: The above image has most of what you need to know at this point. You'll notice that by performing step #1 above, you'll automatically get a layer mask ready to go. You don't have to paint anything in the mask, and can leave it white. Now paint away the B&W layer to reveal the cherry sunburst pattern in the classic Gibson Les Paul guitar...

And there you go!  If you've done everything correctly and with sufficient attention to detail you should have something that resembles my final image... or even better. Personally, I feel that this image needs more work, and was a quick and dirty job. For production work you need to spend more time creating the mask edges... but it's still OK to prove my point for this tutorial.

Photoshop is amazing in the multitude of ways a user can do things. Notice the two masks we painted in this tutorial were essentially the same. There is a way to save the mask after you make it the first time so you can re-apply it later without having to paint it again... but that's the subject of another tutorial. Have fun!