Hi,
Just my opinion....but if I were doing this pattern, I would use 18-count BLACK fabric, then you wouldn't have to worry about any lighter color of the fabric from showing through. Also, it would save you a LOT OF TIME not having to stitch all that background!

Bermuda is right about using black Aida fabric. I do a lot of Mystic Stitch patterns since it is one of my favorite designers, and they usually list white fabric because they have all the background stitched in. If you use a black colored background you will save a lot of time by not having to overall stitch it.

Thank you so much for the advice!

If you do decide to do this pattern on black aida, you will probably want a source of light that shines up through the black fabric from BELOW the fabric, since stitching on black fabric can cause you to have difficulty seeing the fabric holes.
You can increase your ability to see the fabric holes by doing the "poor stitcher's way" which is to put a white towel, pillowcase or sheet on your Lap while you're stitching to see the holes better.
I know there are some stitcher's on this chat messageboard that have other methods of seeing the holes better on black fabric other than my way. Hopefully, they'll see our chat and send you the other suggestions....:)