Illustrator filters, found in the Filter menu (see Figure 17.1), perform a wide variety of tasks, ranging from simple time-savers such as converting all colors to CMYK to more complex functions such as creating intricate borders using the Path Patterns filter. In this hour, we focus on some of these filters, including
The Illustrator Filter menu.
The Filter menu actually started out as a place for Illustrator plug-ins, but now that plug-ins can appear anywhere within Illustrator, the Filter menu has become the dumping ground for functions that don't really belong under any other menu. If you have any third-party plug-ins installed, such as KPT Vector Effects or Extensis VectorTools, you'll find them in the Filter menu. So if you have some filters that are not covered in this chapter, please refer to the documentation that came with those filters. For more information on plug-ins, see Hour 21, "Working Smart in Illustrator."
I've broken down the filters as they appear in the Filter menu, and they fall under the following categories: Color, Creation, and Distortion. The rest are Photoshop-compatible filters that apply to raster objects only.
Before we begin, at the top of the Filter menu, you'll notice two commands: Apply Last Filter and Last Filter. These can be used to quickly invoke the last filter you used. The Apply Last Filter option runs the last filter you used, with the settings you used. The Last Filter option opens the dialog box of the last filter you ran, enabling you to adjust the settings before running the filter. Remember the keystrokes ((Command-E)[Control-E] and (Command-Option-E)[Control-Alt-E], respectively) for these two commands, as there are times when you may want to use a filter repeatedly.
The Color filters are production-based filters that you use to fine-tune colors as well as to address color issues to prepare files for film output (see Figure 17.2).
The Colors filters.
Just A Minute: It's important to point out that these filters do not work on objects filled with gradients or patterns. If you want to adjust them with these filters, you have to convert them into art using the Expand function (refer to Hour 6, "Drawing Bézier Paths,"for detailed information on the Expand command).
The Adjust Colors filter lets you tweak the colors of an object or a group of objects (see Figure 17.3). Similar to Photoshop's Levels command, you can adjust colors by changing the CMYK, Grayscale, or RGB values. You can adjust either just the fill, the stroke, or both simultaneously and preview your results as well (although this may slow down performance). You can even click the Convert button to change all selected objects to your current color mode, indicated in the pop-up menu at the top of the Adjust Colors dialog box.
The Adjust Colors dialog box.
These three filters, Blend Front to Back, Blend Horizontally, and Blend Vertically, do not affect the objects (as the Blend tool does) but affect the fill color within them. You must have at least three objects selected for these filters to work. Upon running the filter, Illustrator blends the color across the selected objects (see Figure 17.4).
After you run the Blend Horizontally filter on the row of circles on top, the color is blended evenly across the circles, as shown on bottom.
These filters--Convert to CMYK, Convert to Grayscale, and Convert to RGB--speak for themselves. When used, any item selected is converted to the color mode chosen. Remember that these filters do not convert gradients or patterns.
The Invert Colors filter, identical to the one found in Photoshop, creates an inverted color (negative) for the selected objects.
This filter is important when preparing spot color jobs for film output. Illustrator enables you to create multiple spot colors with the same swatch name. This may present problems when sending out for film separations because if you have several swatches named "red," how will Illustrator know which one to use? Running the Merge Spot Colors filter checks your document for spot colors with the same name and deletes duplicate swatches, leaving you with only one swatch for each color.
On most print jobs, you may need to set the black ink to overprint (as opposed to knockout, where the top color prints, but the color behind it does not). For simple jobs that require trapping, overprinting the black ink solves most trapping problems. Instead of having to select each object individually, and then choosing the Overprint option in the Attributes palette, simply running the Overprint Black filter saves a lot of time (see Figure 17.5). Refer to Hour 13, "The Pathfinder Commands," for more information on overprinting and trapping.
The Overprint Black filter's dialog box.
The Saturate filter can be a lot of fun (see Figure 17.6). Using a simple slider, you can saturate or desaturate the color in an object or a group of objects. This filter is great for creating subtle changes in color as well as making certain objects more or less vibrant than other objects.
The Saturate filter's dialog box.
Basically time-savers, the Create filters let you do in one step what might normally take a lot more (see Figure 17.7). You'll also find the Object Mosaic filter here, a powerful filter that can be used to create really interesting effects.
Illustrator's Create filter menu.
When you create a mask, the object that is the mask cannot have any fill or stroke attributes. But sometimes you'd like the mask to have a stroke or fill. With the mask selected, running the Fill & Stroke for Mask filter applies a fill and stroke to the mask based on what the mask attributes were before the mask was created.
In other words, if you used a square with a 1 point black rule and a yellow fill to make a mask, running the filter applies those attributes to the mask. The way Illustrator accomplishes this is by creating a new square with a fill of yellow and a new square with a stroke of black and a fill of None and then sending them to the back and front of the mask, respectively.
Although you could actually do this manually, with the filter you can do it in one step.
Object Mosaic is a powerful filter used to create a vector tile-like mosaic based on a raster image (see Figure 17.8).
The image on the left is the original raster. The image on the right is the mosaic created after running the Object Mosaic filter.
Follow these steps to use the filter:
2. Choose Filter
Create ObjectMosaic (see Figure 17.9).
Choosing the Object Mosaic filter.
Setting the options in the Object Mosaic dialog box.
Try different settings to get different results. Remember, you can also run the Object Mosaic filter on objects rasterized in Illustrator with the Rasterize command. Try using Object Mosaic on rasterized type for some cool effects!
This filter creates a set of trim marks (a.k.a. crop marks) around any selected object. Depending on what option you have set in Preferences, Illustrator creates either standard or Japanese style trim marks (see Figure 17.11).
In Preferences, you can choose from either standard (above) or Japanese trim marks (below).
For those of you who like to take reality into other dimensions, Illustrator's distort filters will be right up your alley (see Figure 17.12). Whether it's minor tweaking or major funk, these filters comply with the most twisted and demented tasks. Remember that these filters do not work on gradients or patterns, unless you expand them first. (Try it; twirling an expanded gradient is way-cool!)
The Distort filters in the Filters menu.
For simple, straight distortions, the Free Distort filter lets you edit a selection with four straight points. Dragging each of the points distorts the selection. Clicking the Show Me button previews your distortion in the Free Distort dialog box (see Figure 17.13).
Using the Free Distort filter.
The Punk & Bloat filter, shown in Figure 17.14, does some pretty wild things to art. This filter changes the Bézier curves in a selection to make either sharp points (punk) or round puffy points (bloat), as seen in Figure 17.15.
The Punk & Bloat filter.
The original star is in the center. To the left is the "punked" star, to the right, the "bloated" one.
Of all the distort filters, Roughen is probably used the most and has some very practical applications (see Figure 17.16). The Roughen filter makes objects appear rough by adding anchor points and moving them around. If you keep the settings really low, you can make your art look almost hand-drawn (see Figure 17.17). The Distort filter is also great for creating torn or crumpled-looking paper.
The Roughen filter.
The original star (left) and what it looks like after the Roughen filter is used (right).
The Scribble and Tweak filter, shown in Figure 17.18, is difficult to describe. Based on your settings, Scribble randomly moves anchor points away from the original object, whereas Tweak moves anchor points around on the object, creating interesting distortions, to say the least (see Figure 17.19).
The Scribble and Tweak filter dialog box.
From left to right: the original star, scribbled, and tweaked.
The Twirl filter is really cool (see Figure 17.20). The filter actually curves the art in a circular motion from the center, as shown in Figure 17.21, based on the number you enter in the Twirl filter dialog box. If you want to Twirl an object by eye and watch it change in real time, you can use the Twirl tool, which can be found with the Rotate tool (see Figure 17.22). Click and drag with the tool and watch your selection spin before your very eyes!
The Twirl filter dialog box.
From left to right: the original star, twirled 30deg., twirled 100deg..
Selecting the Twirl tool from the Toolbox.
The Zig Zag filter, shown in Figure 17.23, is another distort filter that wreaks havoc on anchor points. Playing with the settings on this one can also produce some wild and interesting results (see Figure 17.24).
The Zig Zag filter dialog box.
On the left is the original star, on the right is...well, your guess is as good as mine.
So many filters! We covered a lot of ground today discussing all of Illustrator's filters, which enhance our productivity and creativity. You never know when you could use the Roughen filter or even Object Mosaic to add that special touch to your artwork. You're probably wondering about the rest of the filters found in the Filter menu, such as the Ink Pen. Well, hold on to your chair because in the next hour we dive right in to the rest of these filters.
Knockout--Term used in trapping to indicate the top color obliterating any color below it.
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