The version of Black Diamond Pearl that Slingerland and SlingerLeedy used was a larger random pattern that was more lively and had more varying shades of black, gray, and silver than the Black Diamond Pearl wrap used by most other drum makers.
Just for clarity the SlingerLeedy drum pictured is a '58-'61 and has the Black Diamond Pearl wrap used from '56-'72 (some claim the nicest BDP ever produced). The BDP wrap of DrumBob's '48 Radio Kings is a bit different. Here's a link to Dr. Wenks BDP article: http://www.vintagedrumguide.com/drcjw/article_4_finishes3.html