there is no right or wrong side- use the side you like best. i pay for both sides of my fabric and feel it is fine to use which ever side works in my project- regardless of what side some may (think) is wrong.
check out water color quilts- many many squares the (muted) side is used instead of the brighter side.
with batiks as with most hand dyes-both sides are used equally-as both are dyed. printed fabrics may have a more pronounced difference- but both sides are still used when it works for the project.