Field, Todd; Perrotta, Tom (2007-01-02). Little children: The shooting script. ISBN 978-1-55704-777-9. These are just approximations at the leadness based on those from a standard, reliable pencil graphite, like the Mitsubishi Hi-Uni. All the pencils are capable of producing a huge range of shades (one pencil could replace 10 graphite pencils with each of a various softness) They are collectables; all the pencils they produce look unique and special, with the limited-edition pencils all having their own story

Cons• The eraser clip is prone to snapping with overuse (although the pencil itself is not affected) Sondheim, Stephen (2011). Look, I Made a Hat: Collected Lyrics (1981–2011), with Attendant Comments, Amplifications, Dogmas, Harangues, Digressions, Anecdotes and Miscellany. ISBN 978-0-307-59341-2. Laurents, Arthur (2001). Original Story by: A Memoir of Broadway and Hollywood. ISBN 978-1-55783-467-6. It is possible to see that the OPB and the Pearl have darker leads than the mechanical pencil and the 602, but only by a fraction! White, E. B. (2011-10-06). In the Words of E. B. White: Quotations from America's Most Companionable of Writers. ISBN 978-0-8014-6367-9.

The lead hardness varies with each model, not just the aesthetics of the pencils. The softest is the Matte, followed by the Pearl, 602, and then the Natural is the hardest. Forum, via Equality (October 9, 2011). "LGBT History Month profile: Composer, conductor Aaron Copland". www.lgbtqnation.com. Don Bluth's Animation School | on Animation". Archived from the original on 2015-12-08 . Retrieved 2017-05-19. I was amazed by the quality of the OPB, but I did feel like the lead was a bit too soft for my everyday rough pencil sketches or even for the entirety of a more finished sketch. The lead was just too soft and easily blended so my hand was often smudging the pencil lines. I think one of the other two pencils would be great for rough sketching or the beginning sketch, before using the OPB to add more depth, through darker shades, to complete the piece.