Adobe InDesign CS/CS2 Breakthroughs [Electronic resources] نسخه متنی

Separations Anxiety

Print Separations to PDF

It's easy to print separations from the Print dialog box: I just go to the Output panel and choose Separations from the Color popup menu. But when I export an InDesign file as a PDF file, the Export to PDF dialog box is missing the Output panel altogether, and there's no other place where I can choose anything other than full CMYK composite output. I'd like to make a PDF of my separations so I could check them out onscreen instead of wasting a bunch of paper.

Whassamatta, pal, the Separations Preview palette ain't good enough for ya? Just go to Window > Output > Separations Preview to open it up. Select Separations in the palette's View popup menu, and you're good to go.

Okay, okay, don't cry about it. To create a PDF of your color separations, you'll need Adobe Acrobat Professional. Open the Print dialog box, and print separations to the Adobe PDF printer (or to a PostScript file, and run it through Distiller). Don't forget to turn on Page Information in the Marks and Bleed panel before you hit the Print button, otherwise you won't know which plate of which page you're looking at in the PDF.

Where's the Trapping?

I thought InDesign automatically applied trapping. But when I look closely at my color printouts, or zoom in to 4,000% on screen in InDesign, or to 6,400% with the Loupe Zoom tool in Acrobat, I can't see it, even with Overprint Preview turned on. Everything looks kiss-fit. I even tried changing the trap width from the default 0p0.25 to 0p6, and I see absolutely no difference.

Yes, InDesign automatically applies quite intelligent traps (even to gradient edges), but only when you print out color separations. Composite, full-color printouts from InDesign are never trapped. When you turn over a press-ready composite PDF (also never trapped) to your commercial printer, they apply the trapping using their own software, when they output the PDF to separations. The only traps they may honor are any strokes you manually set to be overprinting via the Attributes palette, or in placed images where overprinting was included in the image file.

Note

What's trapping? When objects overlap each other in a layout, like a small cyan frame on top of a larger, magenta frame, the cyan frame "knocks out" part of the magenta frame, leaving a hole. The edge of the top-most object perfectly abuts (kiss-fits) the edge of the knockout, like a jigsaw puzzle piece. If the two objects use completely different colors (inks), and the job is going to be color separated, there's a chance that the paper color might peek through in the final printed pieces, because few high-speed printing presses can maintain kiss-fit registration. Trapping is the practice of setting very thin lines to overprint each other at the edges of these sorts of abutments to compensate for a slight misregistration in film, plate, or press. You can see and modify InDesign's auto-trapping settings by choosing Window > Output > Trap Presets, and double-clicking the [Default] Trap Preset.

Transparency and Your Print Vendor

It comes down to this: InDesign, Illustrator and Photoshop all support transparency, but PostScript does not. Thus, an InDesign file containing transparency (placed images with transparency, and/or native transparency like drop shadows) will need to be flattened not the layers, just the transparent elements before it can be output on a Postscript device. Who should do the flattening, you or your print vendor?

Whenever reasonable, your print vendor should do it. Why? Because their equipment is more powerful than most end users' gear and can process high-res flattening better than yours; because they understand what flattening entails and how to tweak it for the best results on their RIP than anyone else; and finally, because if there are any unwanted artifacts created as a result of flattening, they would be the ones responsible for fixing it.

Just as output providers have purchased high-end trapping workstations (or hired expert pre-press staff to do it, or both) for optimum results in trapping, forward-thinking print vendors are now moving to transparency-aware RIPs or training their staff how to flatten transparency correctly for their press requirements. You want to seek out these people and give them your business! That way, you never have to worry about dealing with the Flattener Preview in InDesign, or fiddle with Transparency Flattener presets. Let your printer take care of it.

Get on the phone right now and ask your output provider if they'll accept either native InDesign files or press-ready PDFs that have been exported from InDesign with Acrobat 5 or higher compatibility. We put that in italics, because that's the only way you can create a "live transparency" (unflattened) PDF from InDesign. If they'll only accept Acrobat 4 files, you know they can't deal with transparency.

It won't work to print to the Adobe PDF printer, or to print to Postscript and then Distill it. Both of these methods are limited to creating Acrobat 4-compatible PDFs, which are flattened by definition.

Exporting to PDF/X1-a won't work either, because part of that format's requirements is that it's Acrobat 4-compatible. The PDF/X1-a format is meant for when you need to create a "blind" PDF (when you don't know who the printer is) such as submitting display ads in PDF format for magazines. Your PDF may end up being imported into a QuarkXPress layout for all you know, which as of this writing only accepts Acrobat 4-compatible PDFs. Unfortunately, a number of commercial printers are glomming onto this blind standard for all their clients. It's not necessary, and since designers can still submit bad PDFs (low res images, 50 spot colors) that pass the PDF/X-1a test, it doesn't do much good.

If your current print vendor goes, "Huh?" when you ask them about flattening transparency, you might direct them to the Adobe Print Resource Center at http://studio.adobe.com/us/print/main.jsp. This page has links to superb white papers that describe in detail how to work with transparency in Adobe files, and they're free to download. One great one (good for designers to read, too) is the Adobe InDesign CS2 Printing Guide for Prepress Service Providers.

Finally, if you'd like to find a printer in your area who can accept native InDesign files or PDFs with live transparency, you can search for one by zip code at Adobe's site. Go to http://partners.adobe.com, and click the Find a Print Service Provider link at the upper right of the page.

Thus, to see InDesign's trapping in action, choose Separations as the Output type in the Print dialog box, and inspect the edges of each color plate that gets printed. Or, print separations to PostScript and run them through Distiller (or print to the Adobe PDF printer) and look at each color's "plate" on-screen.

As an interesting experiment, you can also force InDesign to apply its trapping to a composite PDF, and inspect it in Acrobat or in a color printout of the PDF. Just remember that your print vendor will very likely not be using these settings, unless this is the final file you turn over. And in that case, you'd better warn them that's what you did, and then duck!

Here's the hack to create a trapped, composite PDF from InDesign, courtesy of Adobe guru Nick Hodge:

1.

Choose File > Print, and choose the Adobe PDF printer as your printer.

2.

In the Print dialog box, set up all your options as usual (page range, printer's marks etc.). In the Output panel, change Color output from Composite CMYK to In-RIP Separations, and set Trapping to Adobe Built-In.

3.

Click the Printer button (or Setup button if you're on Windows) at the bottom of the Print dialog box. Change Adobe PDF options to the Press preset, and click Print to back out of the Printer Setup dialog box.

4.

When prompted, name your PDF and choose a location to save it on your hard drive. Click Print again in the InDesign Print dialog box.

5.

Open the PDF in Acrobat. To view the traps (the overprinting strokes), turn on Overprint Preview in the Advanced menu. You may need to use the Loupe zoom tool if your traps are really small.

Trapping is Incorrect in Separations Preview?

I have spot-colored 36 pt. type (that I created in InDesign) on top of a placed Photoshop image. When I view all the "plates" in Separation Preview, and zoom in closely, I can clearly see the traps (the colored strokes) InDesign has applied to the edges of the type. But when I move my cursor over the trap lines to see what colors are being used to create them (according to the Separations palette's ink percentages), the mix is incorrect. I'm not sure how to fix this.

What you're seeing are not trap lines; they're the anti-aliased edges that InDesign applies to text characters to make them look smoother on-screen (Figure 8-9). When you move your cursor over the type edges, Separations Preview is being too helpful and is reading and reporting the mix of inks used in the anti-aliasing. (Actually, InDesign uses RGB colors for this, since it's just for screen preview. But Separations Preview always converts RGB colors to their CMYK equivalents.)

Weird, huh? To see for yourself, turn off the Enable Anti-aliasing checkbox in Preferences > Display Performance and check again. The diagonal and round edges of the text characters now look slightly pixelated, and as you slowly move your cursor over the color transitions, Separations Preview no longer detects any "traps."

As explained in the previous solution, the only way to make InDesign apply trapping is to output separations to a printer or to a PDF from the native InDesign file.

Show Spot Color Plates in DCS EPSs

We have a lot of legacy Photoshop files that were saved as DCS EPSs because they contain spot color channels. When we place these into InDesign, the spot color gets added to the Swatches palette just fine, and it's listed in the Separations Preview palette, but when we view just that spot color's plate using the Separations Preview palette, there's nothing there!

These symptoms point to one cause: The original Photoshop file contained at least one vector layer (a vector shape or live text layer). When the user saved the file as DCS, they left the Save Vector Data option turned on in DCS Format Options dialog box. We're not sure why InDesign has a problem with these, but it probably has something to do with lots of ones and zeroes.

The only way to fix the problem is to locate the original PSD file from which the DCS saved, and either re-save it as a DCS with Save Vector Data turned off, or just use the original PSD file in your document, since InDesign CS and CS2 support spot channels in PSDs. Either of these methods retains the spot color channel information and you'll be able to see the spot color artwork in Separations Preview.

If you try opening the DCS file in Photoshop, you'll lose your spot channel data when the base EPS format of the file is rasterized. Yet another reason to just stick with the PSD format in the future.

Reveal Mystery Colors in Separations Preview

I'm wrapping up a 216-page magazine issue. The job is only supposed to use CMYK colors. Yet somehow, during the past couple weeks I've been working on this puppy, two RGB colors and three Pantone spot colors snuck their way into the Swatches palette. When I choose Select All Unused from the Swatches palette menu, they don't get selected, ergo, they've been used someplace. But for the life of me, I don't know where. How do I find out which objects were filled or stroked with these unwanted colors? There's no "show me where this color is used" command.

The Separations Preview palette (Window > Output > Separations Preview) will show you all CMYK and spot-colored items. (We'll get to the RGB ones in a minute.) To see where you've used a spot color, change the View popup menu to Separations, then hide all the CMYK color separations at once by turning off the checkbox next to the first "color" listed, CMYK.

Zoom way out to something like 25% so you can see at least a few spreads at a time, and scroll through the document. Only the spot-colored items will appear (in their actual spot color), everything else will be hiddenyou'll just see blank pages. If you're looking for a single spot color you've turned off all CMYK and all spots except for one in the Separations Preview palette objects or type using that color will appear as black (Figure 8-10).

Once you spot the item (oh, bad pun!), you can select it, and change the View menu in the palette back to Off. Everything in the document reappears and your item is still selected. Now you just have to fix it.

What about the RGB colors? The Separations Preview palette is actually showing you what the separations will look like after it's been converted to CMYK plus spots. InDesign converts RGB images and colors to CMYK when you print separations, so the palette can't show you the RGB data. To work around it, double-click each RGB color in the Swatches palette and change it to a Spot color. Now they'll be listed in the Separations Preview palette and you can proceed as above. Once you locate the offenders, you'll probably want to change the RGB to a CMYK process color or use the Ink Manager to alias them to a spot color.

If your eyes start to roll back in your head at the thought of scrolling through hundreds of spreads looking for a speck of spot ink, try this slick technique suggested by InDesign master Peter Truskier on Adobe's InDesign forum:

1.

If RGB colors are an issue, convert them to Spot colors in the Swatches palette before you begin.

2.

Choose File > Print. Make sure that the "Print Blank Pages" option is turned off in the General panel of the Print dialog box.

3.

In the Setup panel, turn on Scale to Fit, and in the Marks and Bleeds panel, turn on the Page Information checkbox.

4.

Now go to the Output panel, and in the Color popup menu, choose Separations.

5.

At the bottom of the Output panel, uncheck all colors (inks) except for the first single spot color you're looking for. (You'll repeat this process for each spot you need to track down.)

6.

InDesign is now set up to output only those pages containing that spot color, and on those pages, only those items using that color will appear. (Saving you a ton of time if only one comma in a huge document uses that unwanted spot color!)

If you click the Print button, these pages will be sent to your local printer. To "save some trees," as Peter suggests, change the Printer to Adobe PDF, and print to that you can view the pages in Acrobat.

On your printouts or in the PDF, look at the lower-left corner of each page. Since you turned on the Page Information checkbox, you'll see the page number listed here, giving you the information you need to locate that spot-colored object in your document.