How much do you know about the options for Appearance of Black on RGB Monitors?
Situated at the end of InDesign preferences is Appearance of Black. Which way should it be set? How understandable is the interface instructions? Here is the text of the 5 settings within this preference, augmented with helpful amendments:
On RGB Monitor Screens:
Display All Blacks Accurately: Displaying all blacks accurately will show pure blacks (100K) and rich blacks (blacks with mixed CMYK percentage of ink values) as described by the document. This option will display black as Photoshop does (able to show lighter and darker shades of black).
Display All Blacks as Rich Black: Displaying all blacks as rich black will show both pure blacks (1OOK) and rich blacks (blacks with mixed CMYK values) as rich black. This will not change color values in the document, but all blacks will appear as dark as possible on your monitor screen.
Printing to RGB Printers and/or Exporting to an RGB PDF:
Output All Blacks Accurately: On RGB (and grayscale) devices, outputting all blacks accurately will show pure blacks (100K) and rich blacks (blacks with mixed CMYK values) as described by the document. This option will output black as Photoshop does (able to show lighter and darker shades of black).
Output All Blacks as Rich Black: On RGB and grayscale devices, outputting all blacks as rich black will show both pure blacks (100K) and rich blacks (blacks with mixed CMYK values) as rich black. This will not change color values in the document, but all blacks will appear as dark as possible on RGB devices (your monitor).
Above: The Appearance of Black is a preference in Adobe InDesign that shows detailed descriptions
These above settings have no effect on a CMYK-flavored PDF (nor PostScript output) purposed for prepress use, but the last-mentioned setting does:
Overprint [Black] Swatch at 100%
This is the default setting for InDesign documents that control whether the [Black] swatch overprints other ink colors or not. Generally speaking, all other swatches in the Swatch panel will tend to knockout (remove) other colors when objects and text are layered over other objects and text. Except the [Black] swatch. Its ink applies on top of other ink swatches, causing a deepening of the appearance of black. This is not a worry nor consideration of onscreen RGB-flavored PDFs; but rather a technical choice for CMYK swatches in a printing pre-press workflow.
Notice that this choice specifically says "at 100%". That means it does not affect tints of [Black]. It also doesn't affect unnamed black colors, imported black color swatches that came from Word, or objects that appear black because of their transparency settings, which includes anything in the Effects panel (opacity and blending modes). It affects only objects or text colored with the [Black] swatch used at 100% tint.
Often important, and sometimes it is not
With respect to ink on printing press, a designer has to decide whether or not to have added other forms of black ink swatches, namely built-black swatches often referred to as rich and cool black. These forms of black swatches include a percentage contribution of cyan, magenta, and/or yellow ink in the 4-color printing process. Built-black swatches put more ink on the printing press sheet resulting in a deeper, more-opaque quality to the printed black regions. What percentages should be used depends on the particular commercial printer, the particular printing press, and the particular kind of printing paper. Call and discuss this with your printer.
With complex printing press designs, some areas of the page might need to knockout objects under them, while other areas of the page might need an overprint of ink colors applied to objects. In addition to building additional built-black swatches, these situations require deciding whether to overprint or knockout. For these specific situations, InDesign also provides the Attributes panel to control such things. With the Attributes panel, a designer can select an object and control whether or not to overprint stroke and fill and even the gap color in a dashed line. Another place you might have noticed the ability to assign overprint is in the Character Color section of a paragraph style, as well as a character style.
Further, in order for a designer to see these slightly different appearances of black, and their interactions with other swatch colors, a press-oriented designer also needs to turn on View > Overprint Preview. This allows the monitor screen to simulate for the InDesign user any and all interactions of ink swatches applied to objects, simulating conditions of overprint or knockout. If you work with spot color inks on press, it is wise to turn on this view setting. By the way, Overprint Preview must be turned on each time you open a document. The view setting is not saved within a document.
What a lot of InDesign users forget to do is visit Proof Setup. Here is where you would choose the specific color profile that most closely matches your printing press condition. This does not have the same purpose as Overprint Preview. This is concerned with holding back RGB monitor colors to more closely simulate the limited gamut of color on a printing press. Still, having chosen this correctly, using Overprint Preview can be somewhat more accurate in its simulation to your monitor screen when you choose View > Overprint Preview.
If all your design work is for online, onscreen, website, and social media kinds of publishing, you can ignore much of this printing-press-CMYK-ink-based features. Choices of how the color black appears to you can be OK any way you set it.
