In preview the Ai files shows black. If I open the Ai file the colors are displayed correctly but in a PDF they are totally black. Does anyone know what's going on?
Apple's Preview application can not render spot colors. In addition to a few other rendering bugs. This has been true for years. Apple doesn't appear to really care.
The solution is simple. Stop using Preview to view PDFs if you want PDFs to be rendered correctly. Use Adobe Reader or Adobe Acrobat.