Adobe InDesign CC 2015 - Manual (Page 514)

509
Transparency
Last updated 6/6/2015
If you apply transparency to objects on a spread, all colors on that spread convert to the transparency blend space you’ve
chosen (Edit > Transparency Blend Space), either Document RGB or Document CMYK, even if they’re not involved
with transparency. Converting all the colors results in consistency across any two same-colored objects on a spread, and
avoids more dramatic color behavior at the edges of transparency. Colors are converted “on the fly” as you draw objects.
Colors in placed graphics that interact with transparency are also converted to the blend space. This affects how the
colors appear on-screen and in print, but not how the colors are defined in the document.
Depending on your workflow, do one of the following:
• If you create documents for print only, choose Document CMYK for the blend space.
• If you create documents for web only, choose Document RGB.
• If you create documents for both print and web, decide which is more important, and then choose the blend space
that matches the final output.
• If you create a high-resolution print piece that you’ll also publish as a high-profile PDF document on a website, you
may need to switch the blending space back and forth before final output. In this case, be sure to reproof the color
on every spread that has transparency, and avoid using the Difference and Exclusion blend modes—these modes
can change the appearance dramatically.
Type
When type is close to transparent objects, it may interact with transparent objects in unexpected ways. For example,
type that wraps around a transparent object may not actually overlap the object, but the glyphs may be close enough to
interact with the transparency. In this case, the flattener may convert the glyphs to outlines, resulting in thickened
stroke widths on the glyphs only.
If this happens, do either of the following:
• Move the text to the top of the stacking order. Use the Selection tool to select the text frame, and then choose Object
> Arrange > Bring to Front.
• Expand all text to outlines for a consistent effect throughout the document. To expand all text to outlines, select
Convert All Text To Outlines in the Transparency Flattener Preset Options dialog box. Selecting this option may
affect processing speed.
Image replacement
The flattener requires high-resolution data to accurately process a document with transparency. However, in an OPI
proxy workflow, placeholder or proxy images are used, for later replacement with high-resolution versions by an OPI
server. If the flattener doesn’t have access to the high-resolution data, then no OPI comments are produced and only
the low-resolution proxy images are output, resulting in low-resolution images at final output.
If you work in an OPI workflow, consider using InDesign to substitute images before saving the document as
PostScript. To do this, you must specify settings both when you place the EPS graphic and when you output it. When
you place the EPS graphic, select Read Embedded OPI Image Links in the EPS Import Options dialog box. When you
output, select OPI Image Replacement in the Advanced area of either the Print or Export EPS dialog box.
Color conversions
If a transparent object overlaps a spot color object, undesirable results may occur when you export to EPS format, and
then convert spot colors to process colors upon printing or create color separations in an application other than
InDesign.