Layer Masks 101 (Photoshop)

[Fourluvbugs]

I use masks constantly when I'm editing or putting together a layout and once in awhile someone asks me how they work. I'm posting this here and on my blog on the off chance that someone may find it helpful.

What is a mask?

A mask is tool that operates to hide part of a layer and let another part show through.

There are several kinds of masks: a clipping mask, a vector mask, a layer mask, and probably others. I think there are lots of tuts out there for using a clipping mask since they are such a prevalent tool for using templates, but far and away the masks I use most often, in every single page I make, are layer masks.

A layer mask works by hiding part of the layer and leaving the rest visible while the entire layer remains intact. This makes the layer mask an invaluable tool for non-destructive editing and design, especially if you tend to change your mind a lot and need to move things long after the undo button would do you any good.

A basic layer mask is only two colors: black and white, more complicated masks also have shades of gray. It attaches directly to a particular layer and affects that layer only. The white parts of the mask are clear and reveal the attached layer and the black part of the layer mask hides the corresponding portion of the layer. Where the black is on the mask, it will look on your document as if that part of the layer is erased. Except it isn't erased, which is what makes the layer mask so fabulous.

You can change the mask at anytime in the process or remove it altogether.


OK, enough theory -- how does it actually work?

Here's a step by step on how to use it. It takes a little getting used to, but once you've got it down, you'll never go back!

Here is a picture of a leafy stem and a string (both are from the Spirit of Summer charity kit).


Now let's say you want to twine the string around the leafy stem. How would you do it? Well, if you are reading this, you'd probably get out your eraser tool and erase the leafy stem where you want the string to show through. And that works. It works beautifully! But if you don't like the way you've done it when you open this document tomorrow, you have to drag the leafy stem in again and start your erasing over.

Let's do it with a mask instead.

First, place the leaf layer on top of the string layer. Now highlight the leaf layer and in the layer palette click that little button that looks like a rectangle with a circle inside of it. You just added a layer mask! Hooray!


Now if your PS is set to default to a white layer mask, everything in your document still looks exactly the same. If its set to black though, your leaf layer is no longer visible. No worries! Set your foreground color to pure white and then grab your bucket tool. Because you are working on a a mask right now, your foreground and background swatches are should have automatically set to black and white. You can switch them around by using the x on your keyboard. Click on the layer mask in the layer palette -- make sure you've selected the mask, not the leaves. There should be a double thick border around the mask in the layer palette. If there is, bucket fill your document white. Now you should be able to see the leaves and the layer mask in the layer palette should look white instead of black.

With me so far?

OK, now that the mask is in place, let's start masking out some of those leaves so that we can see the string. The most IMPORTANT thing that you need to get used to here is that you cannot use the eraser. That's right -- NO eraser for you. Use a brush instead. Brush! Again, make sure that your mask is selected in the layer palette. Switch your foreground to black (because we are about to hide some of the leaves) and start painting on the document. If when you paint it looks black, you've got the leaf part of the layer selected instead of the mask part. Fix it and continue. As you paint, the leaves that you are painting should disappear.


Look in the layer palette. See how a section of the layer mask is black now? That's the part that you've masked out. But the leafy twig is still there in its entirety. Nothing has been erased and you can make changes at any time.

If you mask something that shouldn't be masked, just flip your foreground back to white (x) then paint over the mask again and your green leaves should come back. Cool, eh?

Now with something like this you don't want to blindly mask leaves, that just looks silly. Now that you have an idea of how the mask works, let's make it pretty! Paint all the black parts of the mask white and lets start fresh. Since we know that we only want to mask parts of the leafy twig where the string should peek through, Ctrl click on the string layer in the layer palette to select only the string. Then select your mask and brush tool again, switch the foreground to black, and start masking the parts of the leaves where you want to see the string.


Made a mistake? changed your mind? Just flip to white and paint it out!

Voilà!

Look at that twining!


Oh wait, you say you don't want that string at all? delete the string layer, delete or disable the layer mask and your beautiful leafy vine is whole and intact just waiting for the next element of your design.

Once you get the basics down, you can and will use layer masks for everything -- selective coloring, brightening just the eyes on a portrait, you get the idea.

So that's it! I'm happy to answer questions if anything at all is unclear or confusing.

[summmerdays]

Great tutorial Becca! Thanks!!!

[candacesoon]

this is really wonderful! I use PSE 6 so I'm not sure if I have layer masks? Do you know?

[Fourluvbugs]

Thanks girls!

Candace, I don't think PSE has layer masks. I got some interesting results when I googled "using layer masks in PSE 6.0". . . there may be something there that would help?

[summmerdays]

I have PSE6 and I can't find masks anywhere. I have a "PSE6 for Dummies" book and they only talk about text masking (which is pretty cool)...

So, bummer...that tutorial looked very user friendly...

[Fourluvbugs]

Well that totally sucks!! I tell ya, I was happy with PSE until I started trying to do some of this more complicated stuff and then I got really annoyed with it. Grrrr!

[IntenseMagic]

This is awesome!!! Thanks so much for sharing!

[Fourluvbugs]

You are so welcome! I'm glad that you find it helpful.

[IvoryKeys]

There is a work around with PSE6. I'll try to pull some things together and post what I know of the workaround. I'm not an expert by any means but I followed someone's directions that is an expert.

[IvoryKeys]

Click on the layer that you want to mask.
Click on the black and white circle at the top of the Layers palette and choose Levels.
Click okay without making any changes.
Click on the new Levels layer and drag it below the layer your want to mask.
Group the two layers together (I alt click between the two layers).
IMPORTANT STEP: Click on the white mask to select it. If you don't you'll be painting on the wrong layer.

From here you would basically do the same thing as in Photoshop with a brush. Use black to hide what you don’t want seen.

I hope this is clearer than I think I've made it. Try it and let me know how it works for you.
Susan

[charmedeebob]

Thanks Becca, I'm one of those "erasing" gals... no one has ever explained this well enough for me to understand, so thank you so much!

[Fourluvbugs]

You are so welcome Charmaine. I'm not sure whether I've explained it well enough either, so if you get stuck give me a shout and I'll see if I can help.

[babyblueeyesx2]

awesome tut! Anyone have this for PSP!?

[lynnirene]

this is a great tutorial!
I am a little bit of an oddball, since I use the GIMP (it's free and I can give you lots more info if you want)...but my point is, GIMP does have layer masks and I use them ALL the time! If you only have PSE, the GIMP does do things that PSE doesn't, so it might be worth checking out. Just an fyi!

[Amerilla]

I really wanted to figure out how to use this tutorial in PSE 7, but wasn't really having any luck. I found a layer mask download and wanted to share it with anyone else in need of some help.

http://graphicssoft.about.com/od/pse...ermasktool.htm