2-color labels are not printed clearly from a Mac.
Make sure you are using the CUPS printer driver when printing 2-color labels.
AirPrint does not support 2-color printing.
To choose the CUPS printer driver, perform the following steps:
From the Apple Menu, open [System Settings]/[System Preferences] - [Printers & Scanners]/[Print & Scan].
Choose your printer in the [Printers] section.
Verify which printer driver is used.
If [Model name + AirPrint] is displayed next to [Kind], the AirPrint printer driver is chosen.
The AirPrint printer driver does not support P-touch Editor, so you should add the CUPS printer driver.
Click [Add Printer, Scanner, or Fax] or the [+] button.
Click the [Default] icon which is located at the top of the dialog box.
Choose your printer from the [Name] list.
Make sure that "[model name] + CUPS" is selected in the [Use] list.
If you cannot find the "[model name] + CUPS", the CUPS printer driver is not installed. Download and install the latest CUPS printer driver from the [Downloads] section.
Click [Add].
The printer is now available in the [Printers] section.
Choose [Quit System Settings]/[Quit System Preferences] from the Apple Menu.