Indeed, light refers to the color. There's also dark, buff, and a few others I think. Light is predominantly white in color with a black tail, dark is predominantly black in color and the females are penciled, and buff is blonde in color with a black tail.
Do you mean standard blue? Blue is laced and does not breed true. Self blue is not laced and breeds true. Blue is always heterozygous (one of each alleles required to make it), and self blue is always homozygous recessive (2 of the same recessive gene required). Regular blue also tends to be darker than self blue. Blue only affects the black pigment, self blue masks both black and colored... I think.
