No, that only affects PhotoShop PSD files and roadsigns.
Are you viewing the PDFs in Preview or Adobe Reader? In Adobe Reader there are some accessibility options (ie for blind / vision impaired people) under Help -> Accessibility setup assistant. I can't see purple as an option in it, though there is green, black and blue.
Here's some info if it helps..
Document Type DF Document
File size 17380085: bytes
Page size: 20.6 x 27.3 cm
PDF version: 1.5
Page count :98
Encryption: None
Modification Date: 11/11/05
Content Creator :Adobe Acrobat 6.0
PDF Producer: Adobe PDF Library 5.0.2
Creation Date :11/02/05