I highly recommend avoiding self publishing authors. They rarely work out for a number of reasons.
- They aren't trained as an art director and have no idea how to work with an artist
- They pay way below industry rates in exchange for "more money once it's selling"
- The stories haven't been vetted and typically aren't professional quality
- They don't understand how the business works and have little to no plan of distribution
- They don't understand all the costs involved. More on that:
Typically there are quite a few parts to being a self published author. The EASY part is getting the book made. The hard part is selling the book. This requires an actual business and marketing plan. Most authors tend to over value their work and think as long as it gets made, it will do well (cause, you know, it's awesome!). But, it doesn't typically work that way. Most self publishing projects rarely see the light of day, and the ones that do die on the vine due to no plan for distribution.
So IF you must work with an author. Demand a LARGE upfront payment, royalties on the back end, and ask to see the business plan for sales and distribution.
If you are wondering what a "large upfront payment" (advance) would be, I'd start here:
If you, the artist, are unpublished: $7500-$12000
If you have 1- 5 books: $12,000-$20,000
If you have over 5 books: $25,000+
Hope that helps. : )