Can I alter total ink coverage in Acrobat CC or does it have to be changed in PhotoShop?

Leave images in RGB. If you place them in InDesign, don't convert them in CMYK before. Best would be to export a PDF/X-4, but if the printer insists on CMYK files, export as PDF/X-1a with the correct output profile. This will respect the maximum ink value.

First of all, to be very clear, Adobe Photoshop is not a PDF file editor. When you open a PDF file in Acrobat (with the exception of a Photoshop file saved as a PDF file in Photoshop with the option of maintaining Photoshop layers for subsequent editability), all content of the PDF file is converted to raster bitmap at a particular resolution that you specify in a color space that you specify. Thus, if you have vector and/or text content, that content is effectively “ruined” in terms of its subsequent use in any color space or resolution. This is not an accepted PDF publishing workflow practice, and especially not for print!

In terms of total ink coverage of particular objects in a PDF file, if the objects are not in their final color space, for example RGB items with an ICC profile or even CMYK items with an ICC profile and the PDF file is a PDF/X-4 file with an output intent profile that properly defines total ink coverage, then upon color converting and rendering objects during the RIP process, the color conversions for each such object are done in a manner such that such limits are honored. Note that I said for each such object and also note that this doesn't hold for DeviceCMYK objects whose CMYK values are used as-is. Overprinting DeviceCMYK objects, each of which already are within a desired total ink coverage may and very do cause situations in which the desired total ink coverage is exceeded.

Note that very often, RIPs for CtP and especially for digital printing devices (toner, inkjet, etc.) have post-rendering features that indeed check for and reduce total ink coverage to avoid toner adhesion problems, overinking for inkjet, or even wasted ink/toner. You might want to check with your printer or your printer's manufacturer's support organization with regards to behavior of particular RIPs and printers.

          - Dov