Adobe illustrator cs4- P19 ppsx

CHAPTER 15: PREPRESS AND PRINTING 514 In truth, transparency has always been around—in raster form—in Adobe Photoshop. The only difference now is that you can apply these effects in vector form and still edit them late in your workfl ow. At the end of the day, these transparency effects will become rasterized, leaving you with the same result as if you had done everything in Photoshop. In any case, let’s take a closer look at what transparency is and how it works. Understanding Transparency Flattening Let’s start with a simple fact: PostScript doesn’t understand transparency. As you probably know, PostScript is the language that printers and RIPs speak. Native transparency is understood only by PDF language version 1.4 or newer (fi rst present in Acrobat 5 and Illustrator 9). To print objects with transparency, Illustrator must “translate” any transpar- ent artwork into a language that PostScript understands. This translation process is called transparency fl attening. The process of fl attening is simple, and Illustrator follows two cardinal rules when performing fl attening on a fi le: 1. All transparency in the fi le must be removed. 2. In the process of performing rule #1, the appearance of the fi le cannot change. Both of these rules are followed during the fl attening process, with no exception. Obviously, all transparency has to be removed because PostScript doesn’t know what transparency is. Additionally, if removing the transpar- ency would result in your fi le changing in appearance, that would mean you could design something in Illustrator that couldn’t be printed, which doesn’t make sense either. If you think about it, if you’re removing transparency from the fi le and you’re also keeping the visual appearance of the object, something has to give, and that something is the editability of your fi le. Let’s take a look at an example of this. Flattening Artwork Let’s try an example of fl attening: 1. Draw two different-colored circles, one overlapping the other. 2. Set the top circle to Multiply (Figure 15.10). NOTE If you’ve used Photoshop before, you may be familiar with the term  attening, which com- bines all layers in a document. Although similar in concept, transparency  attening is di erent. LEARNING THE TRUTH ABOUT TRANSPARENCY 515 The nice feature of transparency is that you can move the top circle around or change its color, and any overlapping areas will simply mul- tiply. The problem is that PostScript doesn’t know what transparency is and doesn’t know how to print that overlapping area, so transparency fl attening is required. 3. Select both circles, choose Object > Flatten Transparency, and click OK (don’t worry about the dialog box, which we’ll get to later). The fi le is now fl attened. Does it look any different? It can’t, because of rule #2, but the fi le now no longer contains any transparency and can be printed on a PostScript device. The difference is that the fi le is no longer editable as it was before it was fl attened. Upon selecting the cir- cles, you’ll fi nd that the two transparent circles have now been broken up into three individual opaque shapes (Figure 15.11). This fl attening process happens every time you print something with trans- parency. However, the fl attening happens in the print stream, not to your actual Illustrator fi le. When you choose to print a fi le, Illustrator fl attens a copy of your fi le and sends the fl attened fi le to the printer, while leaving your document intact. It wouldn’t be good if simply printing a fi le rendered it uneditable. In our example, we specifi cally fl attened the fi le using the Figure 15.10 By setting the top circle to the Multiply blending mode, you can see through it to the circle below, even with Opacity set to 100%. Figure 15.11 Once the objects are  attened, the artwork is split up into individual opaque pieces, called atomic regions. CHAPTER 15: PREPRESS AND PRINTING 516 fl atten transparency function to see the results, but under normal circum- stances, you would not fl atten the transparency manually—Illustrator would do that for you automatically at print time. So, when you print a fi le with transparency, this fl attening process occurs so that a PostScript printer can print the fi le correctly, and this process happens on the way to the printer, so your Illustrator fi le is not affected in any way. This example of the two overlapping circles is a simple case of fl attening. However, other examples can display certain side effects. Let’s explore such a case. Flattening with Rasterization Let’s create another example: 1. As in the previous example, create two overlapping circles. 2. Set the top circle to Multiply. 3. Fill each circle with a linear gradient, but in one of the circles, apply the gradient on a 45-degree angle. The result is two circles with gradients, but the area in which these two shapes overlap appears as two gradients traveling in different directions (Figure 15.12). When this fi le is fl attened, you know that the result will be three sepa- rate shapes as in the previous example; however, this example is a bit different. Although gradients can be preserved in vector form, there’s no way to describe a crisscross gradient, like you see in the overlapping area, as a vector. Because of rule #2, Illustrator is not allowed to change NOTE Flattening also happens whenever you save or export your  le to a format that doesn’t understand transparency. For example, EPS (which is PostScript) and PDF 1.3 do not support transparency. Figure 15.12 This  gure shows two overlapping circles, each  lled with a gradient on a di erent angle. LEARNING THE TRUTH ABOUT TRANSPARENCY 517 the appearance of your fi le during fl attening, so the only course of action Illustrator can take is to turn that overlapping area into a raster image. 4. Select both circles, choose Object > Flatten Transparency, and click OK. You’ll fi nd that although the fi le looks the same, it now consists of two vector shapes and a raster image in the middle. Illustrator creates a vec- tor mask for the middle shape so that the fi le will print correctly (raster images are always rectangular in shape). It’s important to point out that Illustrator didn’t raster the entire fi le; it merely rasterized the portion of the fi le that could not be preserved in vector form (Figure 15.13). At this point, a question should be forming in your mind: If part of the fi le is now a raster image, what is the resolution of that raster? Patience, young Padawan; we’ll get to that soon. Here’s a review of what you’ve learned to this point: • Transparency fl attening is required to correctly print a fi le with trans- parency to a PostScript device. • Transparency fl attening happens automatically, in the print stream, when you print a fi le with transparency from Illustrator, InDesign, Acrobat, or Adobe Reader. • Transparency fl attening may cause certain parts of a vector fi le to become rasterized to prevent a fi le from changing in appearance. Using the Two Levels of Rasterization In the previous example, where two vector shapes resulted in a portion of that fi le becoming rasterized, Illustrator had no choice but to rasterize Figure 15.13 Where appearance can’t be preserved in vector form, Illustrator converts parts of a  le into a raster. CHAPTER 15: PREPRESS AND PRINTING 518 the middle region because there was simply no other way to preserve the appearance in vector form. This is one level of rasterization. However, in some cases a second level of rasterization may occur, even if the appearance of a fi le could be preserved in vector form. Before printing a fi le, Illustrator analyzes the entire document and looks for complex regions containing many overlapping objects (which would result in a large number of atomic regions). Illustrator may then choose to rasterize those complex regions for performance reasons. Although we’ve been trained to think vec- tor objects are simpler than their bitmapped counterparts, try to imagine an Illustrator graphic fi lled with many overlapping objects with transparency applied (Figure 15.14). Although it may seem like only several objects at fi rst glance, once those objects are broken up into atomic regions, you may be looking at thousands of vector shapes, which can take a long time to pro- cess and print (Figure 15.15). In those cases, Illustrator can save precious RIP and processing time by rasterizing these complex regions. Figure 15.14 Using the Symbol Sprayer tool, you can easily create a  le that contains many overlapping shapes. You can also make some of these symbols transparent with the same tool. LEARNING THE TRUTH ABOUT TRANSPARENCY 519 As far as the fi rst level of rasterization goes, you really have no choice but to allow Illustrator to rasterize objects where it needs to do so. What you can do, however, is learn how to build fi les that work around this issue (see “Understanding Object Stacking Order and Transparency Flattening” later in this chapter). With regard to the second level of rasterization, you can control how liberal Illustrator is when looking for complex regions. In fact, you can even disable this second level of rasterization altogether. Finally, with either level of rasterization, Illustrator always gives you total control over how these areas are rasterized. Understanding the Transparency Flattener Settings As mentioned earlier in this chapter, Illustrator has three transparency fl at- tener presets that you can choose from in the Advanced panel of the Print dialog box. These settings control how fi les with transparency are fl attened at print time. To access these settings, choose Edit > Transparency Flattener Presets, and click the New button to defi ne a new preset. Let’s explore the settings in the Transparency Flattener Preset Options dialog box (Figure 15.16). Figure 15.15 Even though you may have started with a small number of objects, the resulting number of atomic regions can be extremely large because of  attening. CHAPTER 15: PREPRESS AND PRINTING 520 • Raster/Vector Balance. This slider is what controls how liberal Illustrator is when looking for complex regions to rasterize (what we defi ned previously as the second level of rasterization). A number closer to zero (0) gives Illustrator more freedom to rasterize at will, resulting in faster print times. Moving the slider closer to 100 results in fewer ras- terized areas but longer print times. At the 100 setting, Illustrator does not rasterize any parts of the fi le for performance reasons, effectively disabling the second level of rasterization. The High Resolution fl at- tener preset uses this setting. In cases where fi les are taking extremely long to print (or crashing the RIP altogether), adjusting this slider to a slightly lower setting helps. • Line Art and Text Resolution. In cases where Illustrator is going to rasterize line art or text, you can specify a resolution that results in good- looking, sharp output. You’ll notice that the High Resolution fl attener setting specifi es a resolution of 1200 ppi, ensuring that text elements and vector objects still have nice, clean, sharp edges in fi nal output. • Gradient and Mesh Resolution. Because gradients and meshes are continuous tones in nature, they don’t require a resolution as high as line art or text. In fact, anything twice your line screen is probably getting thrown out anyway. Therefore, Illustrator uses this setting to rasterize elements that can afford to be set at a lower resolution. You’ll notice that the High Resolution fl attener preset uses a value of 300 ppi. • Convert All Text to Outlines. In cases where text is going to be raster- ized, chances are that the rasterized text looks a bit chunkier than regular vector text. To compensate for this, you can turn on this option to con- vert all text to outlines, giving a consistent chunkier look to all of your text. If you use the method described later in this chapter to move text onto its own layer, you’ll rarely need to concern yourself with this setting. Figure 15.16 You can de ne your own custom  attener settings, or your printer or service provider can de ne them for you. NOTE The two resolu- tion settings in the  attener controls are used whenever vector objects are forced to become rasters during the  attening process. However, live e ects, such as Feather and Drop Shadow, use the Document Raster E ects Resolution setting to determine their resolutions. LEARNING THE TRUTH ABOUT TRANSPARENCY 521 • Convert All Strokes to Outlines. Similar to the previous setting, this compensates for disparity between vector and rasterized strokes by con- verting all strokes to outlines. • Clip Complex Regions. We mentioned that Illustrator can look for complex areas of a fi le and rasterize them for performance reasons. However, we know that raster images are always rectangular in shape, which means it’s possible for “innocent” parts of your fi le to become rasterized simply because they fall into the rectangular bounding box of the area that is complex. More often than not, this results in stitching, or noticeable boxes and color shifts. The Clip Complex Regions option avoids this issue by creating a clipping mask around any rasterized com- plex region (so the rectangular-shaped raster is masked by the vector outline of the object). As you can probably understand, this makes for even more complex fi les and can result in longer print times as well. This option is turned on by default but isn’t applicable in the High Resolution preset because no complex regions are rasterized at all with that setting (because it has a Raster/Vector Balance setting of 100). Understanding Object Stacking Order and Transparency Flattening When rasterization occurs during transparency fl attening, the last thing you want to see turning into a raster is text. That’s because you always want text to be clean and sharp in your printouts. Even at the High Resolution setting, where text is rasterized at 1200 ppi, that resolution is still less than half of what most imagesetters set text with—usually upward of 2400 ppi. Although it’s true that under certain circumstances rasterization must occur in order to print a fi le and maintain its appearance, the way you build your fi les can affect how often this happens. Let’s look at a simple example that clarifi es this: 1. Draw a circle, and add a drop shadow to it by choosing Effect > Stylize > Drop Shadow. As you learned in Chapter 8, “Working with Typography,” the Drop Shadow effect is a raster-based effect, and when transparency is fl at- tened, the drop shadow becomes rasterized. CHAPTER 15: PREPRESS AND PRINTING 522 2. Switch to the Type tool, create some text, and position the text near the drop shadow (Figure 15.17). 3. With the text still selected, choose Object > Arrange > Send to Back. 4. Now select both the circle and the text, choose Object > Flatten Transparency, and click OK. Upon close inspection, you’ll see that a portion of the text was raster- ized. This happened because the text was below the drop shadow in the stacking order, and to maintain the fi le’s appearance when the drop shadow was rasterized, Illustrator had to include part of the text in the drop shadow’s bounding area (Figure 15.18). Figure 15.17 Placing text near an object is common, especially when you’re add- ing captions or credit text near photographs. Figure 15.18 To maintain the appearance of the  le, Illustrator rasterized the text that was behind the drop shadow. LEARNING THE TRUTH ABOUT TRANSPARENCY 523 5. Choose Edit > Undo to go back to the version before you applied the Flatten Transparency function, and select the text object. 6. Choose Object > Arrange > Bring to Front. 7. Select the circle and the text, choose Object > Flatten Transparency, and click OK. In this case, the text, which was above the drop shadow in the stacking order, was not affected at all and was not rasterized (Figure 15.19). When using transparency features in Illustrator (or InDesign, for that mat- ter), it’s important to make sure that text always appears above objects with transparency to avoid unwanted rasterized text issues. Of course, some designs call for text to appear beneath transparent objects, and in those cases, you don’t have much of a choice. Does My File Contain Transparency? Not every document needs fl attening—only those with transparency in them. The tricky part is that transparency can be introduced into an Illustrator document in several ways: • You apply a blending mode or an Opacity value other than 100% in the Transparency panel. • You apply the Effect > Stylize > Drop Shadow feature. • You apply the Effect > Stylize > Feather feature. Figure 15.19 If the text appears above the shadow in the stacking order, the text is not rasterized during  attening. [...]... preferences in Illustrator are application-based, meaning they aren’t saved in each Illustrator document but rather in Illustrator s application preferences file (see the sidebar “The Illustrator Preferences File”) This means if you open an Illustrator file that was created on another computer with different preferences, your own preferences don’t change 536 APPENDIX: APPLICATION PREFERENCES The Illustrator. .. time, Illustrator generates a new one) You can delete the preferences file automatically by pressing Command-Option-Shift (Ctrl-Alt-Shift) while launching Illustrator Keep the keys pressed until you see the splash screen appear Alternatively, you can manually delete the file, which you can find in the following location: Mac OS: Username/Library/Preferences /Adobe Illustrator CS4 Settings/en_US /Adobe Illustrator. .. effect should blend into the background (Figure 15.26) Figure 15.25 When saving the file from Illustrator CS4 and viewing or printing the art outside of Illustrator, the transparency effect seems to disappear Figure 15.26 When saving the file from Illustrator CS4 and viewing or printing the art outside of Illustrator, a white box appears around the transparency effect UNDERSTANDING OVERPRINTS 533... knockout by specifying an overprint The thing is, Illustrator already knows this, so no action is required on your part When you print your file from Illustrator, all these settings are done automatically, so your file looks great when you print it—either as a composite or as separations The same applies when you save your file from Illustrator as a native Illustrator file and place it into InDesign or when... (let’s say Pantone Blue 072 and Red 032) The logo has a drop shadow behind it, and you’ve correctly set the Illustrator Drop Shadow effect to use the Blue 072 spot color, not black On the Illustrator artboard, the logo appears correctly against the spot color background (Figure 15.24) Figure 15.24 In Illustrator, the Drop Shadow effect appears correctly against the spot color background Then you save the... or newer But when you save your file to a format that doesn’t support transparency, Illustrator has to flatten the transparency And in that process, Illustrator realizes that in order to preserve the spot colors so that they print in separations correctly, the drop shadow must be set to overprint the background color (in Illustrator CS4, the spot color is set to overprint instead) The problem is that overprint... you can find in the following location: Mac OS: Username/Library/Preferences /Adobe Illustrator CS4 Settings/en_US /Adobe Illustrator Prefs Windows: Documents and Settings\Username\Application Data \Adobe\ Adobe Illustrator CS4 Settings\ en_US\ AIPrefs If you make many changes to your preferences file, you’ll lose the changes when you delete your preferences file For this reason, you might consider making... being selected) Append [Converted] Upon Opening Legacy Files When you open files that were created in previous versions of Illustrator (what Illustrator refers to as legacy files), you may have to adjust text objects To prevent you from accidentally overwriting your original files, Illustrator tacks on the word [converted] to your file name when it opens legacy files For more information about text and legacy... value determines how close your pointer has to be to another object in order for it to snap to it Anchors Illustrator offers three ways to display anchor points The difference between each size may be subtle here, but this setting can help make Illustrator seem more familiar to FreeHand users Handles Illustrator offers three different ways to display control handles The difference between each of the three... clicking the Refresh button in the panel, Illustrator highlights specific areas in your file in red, indicating where rasterization will occur You can enlarge the panel to see a larger image, and you can also click inside the preview area of the panel to zoom in closer to see more detail From the Highlight pop-up menu, you can choose from a variety of items that Illustrator will preview If all the items . the  le from Illustrator CS4 and viewing or printing the art outside of Illustrator, the transparency e ect seems to disappear. Figure 15.26 When saving the  le from Illustrator CS4. However, the fl attening happens in the print stream, not to your actual Illustrator fi le. When you choose to print a fi le, Illustrator fl attens a copy of your fi le and sends the fl attened fi le. middle. Illustrator creates a vec- tor mask for the middle shape so that the fi le will print correctly (raster images are always rectangular in shape). It’s important to point out that Illustrator