Blue is often referred to as Andalusian blue, and is dominant.  Two Bl genes will give you a splash, one gene is blue, no genes is normal
Lavender is often referred to as Self Blue, and is recessive.  Two lav genes will give you a self blue, one gene is a carrier, no genes is normal.
Andalusian blue varies greatly in color and appearance.  It sounds as though you may have a splash, which is homozygous Bl/Bl
Self blue is generally a very even, pale color, and the lav gene works on red as well.  It is the gene responsible for turning a Mille Fleur into a Porcelain.