yes, the point of this is to try and get one's that become mostly black. If she has any black in here at all due to basic genetics, then it'll be like this since that black betta has black
blue blue 25%
black blue 50%
Black Black 25%
BUT. She does not probably ave black. But your black in the male betta seems to be dominate over blue, yet still allows it to show. I'd expect maybe 4-6 pure blacks from a spawn, 100+ of blue blacks, and then maybe 20 blues?
And i think the term "wash" only applies to red because of how dominate its color is once in the gene pool.