Optimum InDesign PDF Export Color Conversion Settings for Print

Hi @Randy253370084f7r , If you want to force all color to CMYK on an Export, set the Output Color Conversion to Convert to Destination with the Destination set to Document CMYK (the default PDF/X-1a preset sets the Destiantion to Document CMYK). That will convert all color to your document’s Assigned CMYK profile (for an existing document see Edit>Assign Prodfiles..., not Color Settings). When you choose Document CMYK as the Destination, Convert to Destination and Convert to Destination(Preserve Numbers) produce the same result--the native CMYK colors and Swatches Export unchanged.

In order to get the best conversion you need to know the profile of the destination press, which you would normally get from the printer. All of the CMYK profiles provided by Adobe are for offset print destinations. If the output is to an offset press running an uncoated sheet, your assigned CMYK profile should be an uncoated profile (e.g., Uncoated GRACoL 2013)