If you have ever downloaded (or not) one of my free sets of buttons or web page elements, you might notice that I use a lot of opacity masks in my Illustrator files. I do this for a number of reasons, some of which may be obvious, but I would like to clarify a little better on how to use these (opacity masks), and why.
An opacity mask is essentially like a mixture of a clipping mask and a layer mask at the same time. in other words, you can use an opacity mask to control the appearance (transparency of a shape) using, in most cases, a black to white gradient. Because you can't fill an object in Illustrator with a gradient that has transparency, we can use a mask to take away all of the areas covered by the black part of the gradient (or gray in some cases). There are many uses, which I'm sure you will discover rapidly on your own, and soft opacity gives illustrator a whole other dimension to work with. Before going through this tutorial, you must be aware of certain terms:
Offset: Color or offset in contrast to any other shape of same size and color.
Opacity: refers to unclear or partially transparent surface such as fog. Opacity mask serves to combine different colors in uniform pattern so that the whole picture appears to be unique and clear.
An “Opacity Mask” refers to a mask in Illustrator that you place over an existing shape that controls its transparency based on the values of black and white in the mask. White being visible, black being transparent, and all shades of gray are in between on the opacity scale. Opacity mask helps you to apply and orient the different colors according to the background automatically without making any effort manually. It helps you in crafting the best contrast and overall makeup between the two surfaces. It is a pretty long and interesting process and I hope that you will love going through it. But, condition is that you do it in right way. You can create unique series and patterns of colors by using these few simple steps. You should be making slight changes to the colors and customization to find out the way it really works. different colors in uniform pattern so that the whole picture appears to be unique and clear.
Opacity masking is the technique in which different colors are substituted for the other color uniformly so that to create a continuous pattern of colors. If correct colors are used and uniform pattern is made, a lot can be achieved and showcased to the audience. It is common to see such opacity masks on cover of booklets or advertisements. Adobe illustrator helps you use these features to illustrate the things of your choice in the assertive and best possible way. We hope that you will enjoy this tutorial and try to achieve maximum out of it.
First make a background shape so you can see the mask work (I used dark brown).
Select your background shape and lock it. You can do this by hitting Command + 2 Mac, or Control + 2 PC. Or the object menu:
Now make a shape on top of your background and fill it with a different color.
Now we need to make a mask for our shape. The easiest way I've found is to use “Offset Path,” because it is more precise than simply making a new shape on top. Keep your top shape selected and go to the Object menu and select Path > Offset Path.
Offset Path Settings: I usually set this to a 2 pixel offset, with the Miter setting. (positive pixels makes the new shape bigger, negative smaller). I'm not sure what miter limit is yet, haven't played with it. I usually leave it at the default value.
Once you click OK, Illustrator will make you a new shape, perfectly aligned with the original, and 2 pixels larger on each side! Like this: (Showing in wire frame view)
The only problem is (from my experience) Illustrator might place the new shape behind the original. Now simply select your new (bigger shape) and bring it to the front.
Now fill your top (mask) shape with a black to white gradient.
Once you have your gradient fill, select both of your shapes Like this: (You can simply do this by clicking and dragging, since we locked our background)
With BOTH shapes selected, go to your transparency palette, and in the upper right, click on the little arrow. (Palette Options) Select “Make Transparency Mask.”
Result: All areas of the gradient containing white will be opaque. All black will be transparent, and grays are a mixture (the fade). If you don't want to take your shape all the way to transparent, replace your black side of the gradient with a shade of gray.
Tips for exploring this on your own:
1. This can be applied to ANY shape, so think outside the box, but be aware that it increases file size quite a bit, so keep an eye on file size if you find illustrator running slower.
2. The gradient is the master. Change the gradient, change the mask, but you must use black and white.
3. Explore your options in the Transparency palette (mask is clipping) For example, you can use a simple shape and have a complex Opacity mask if “Mask is Clipping” is enabled. In other words, take advantage of this feature as not only an opacity mask, but a clipping mask at the same time. This gives you greater control over the starting and ending values (opacity) of your gradient.
4. There is no (as far as I can tell) shortcut to apply an Opacity Mask. If you want to backup, you will have to release the mask in the same way you applied it; from the Transparency Palette Options, or undo.
Download the .ai, .eps, and .svg here.