The white lines you are seeing on the PDF are due to the transparencies being flattened and these are rendered (shown on screen) in Adobe Acrobat. There are options in Adobe Acrobat to toggle these on/off, here’s how:
In Adobe Acrobat, follow these steps:
- Select the File menu item and then Edit.
- Click on Preferences, then look for Page Display on the left.
- Under the Rendering section, de-select the Smooth Images option.
This will stop the white lines from being displayed.
It is highly recommended when viewing PDF files, that this is done through Adobe’s Acrobat, Reader or Professional, rather than Apple’s Preview.app or from within your browser.