Here’s a quick tip for more accurate rendering of blacks in Illustrator and InDesign. Under the Preferences menu you’ll find a tab for Appearance of Black. The screenshot here is from Illustrator but the settings are the same in InDesign.
There are two settings, one for On Screen and one for Printing/Exporting. By default these are set to render all blacks as Rich Black ie as a black as the device will allow. This is a particular issue when working in CMYK as you will perceive no on screen difference between a single colour black, comprised of 100% Black ink, and a 4 colour composite black, which could run up to 400% (100% in each ink). When printed there is a marked difference between the two.
The two example previews in the panel give an exaggerated view of how this difference will appear but it does give some idea.
Mousing over the dropdown menus will call up information in the Description field explaining the differing behavior for each setting.
If you are creating artwork for print I would urge you to change the On Screen setting to Display All Blacks Accurately as this will give you a more reliable display that closely represents how blacks, both single colour and composite, interactive with other colours in your document.
Depending on the set up of your printing device you may find that the Print/Exporting setting has no impact. Printing devices configured with colour management will tend to use CMYK colour as their input source so the Preference setting is ignored as it only applies to RGB devices.
More basic printers, like standard office printers, tend to use RGB as their input source so this setting will come into effect in this scenario.
As this second option applies to Exporting as well as printing you may need to change this when exporting a CMYK graphic to RGB. However, this would only be necessary if you actually wanted to see a difference in the black elements in your graphic. For the most part black tends to be rendered as rich black with on screen graphics. When viewing black text in a web browser, for example, you will be viewing a full-strength RGB black so only change this setting if it’s relevent.