I'm going to assume you mean a generic PDF icon rather than an "black PDF page"--you probably have your desktop and Finder windows set to show icon previews, and the Finder is therefore drawing an icon preview for you. The Dock doesn't do this. If the item you drag into the Dock has a custom icon (as do many graphics files) that's what is displayed. If the item does not have custom icon, then a generic icon for that file type is displayed. One thing you can do is open the PDF in Preview, go a distinctive looking page, select Copy from the Edit menu. Then go back to the PDF file in the Finder, select GetInfo from the Finder's File menu, click the wee little icon in the upper corner, so that you can see a faint blue border around it, and select paste. The distinctive page will now be the icon for the PDF, and the Dock will display it.
Francine
Francine
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