This is what I want to know. I have 3 blue, 1 black and a white splash, about 8 months all purchased as blue. Then I have 4 lavender about 4 months. Should I cross them? And what would I get if I do?
The blue gene dilutes black also, but it's partially dominant, whereas the lavender (aka self-blue) is recessive. It's not recommended to breed self-blues to regular blues/splash, though I'm not sure why.
If you breed lavender to black, all offspring are black, but carry the lavender gene. A cross of those back to lavender, gives 50% lavender and 50% split (half look like each parent). If you cross lavender to blue, half will be black and half blue, but all carry the lavender gene, because as far as the blue gene is concerned, a lavender is black. If you cross splash to lavender, all the offspring will be blue, but carry the lavender gene.
All of those lavender carriers make the next generation more interesting. For ex. the last case, blue carrying lavender, will produce a whole lot of different colors if bred together. I could compute the genotypes, but I'm not sure what a blue or splash looks like when heterozygous for lavendar. Probably very light colored. Perhaps someone who's done it can tell us the results.