Blue and self blue can be considered the same plumage color. Most often when breeders refer to blue ( also andalusian blue) they are talking about the phenotype produced by the blue gene. This gene is incompletely dominant so if a bird carries one blue gene the bird is a diluted black color or blue. A single blue gene dilutes a genetically black chicken to a blue color. If a bird carries 2 blue genes then the black plumage is diluted to a splash plumage- a light gray to white plumage that has splashes of blue/dark blue.
Incorrect. Blue and Self blue are not even close to the same plumage color. They are two different genes, and are completely unrelated.
Self blue refers to a chicken that has blue plumage that covers the entire body with no other colors in the plumage. Self blue many times refers to birds that are lavender. Lavender is a recessive gene; two lavender genes will dilute a genetically black chicken to a uniform blue color.
Self blue/Lavender not only dilutes black, it also dilutes red/gold coloring.
Most often when breeders refer to self blue they are talking about a lavender chicken and not a blue chicken, Chickens that carry one blue gene can also carry other genes that produce other plumage colors or secondary plumage colors- blue laced red is an example of a secondary plumage color- this is a red/gold chicken with a single blue lace on a feather. This bird carries blue but is not self blue because of the red.
The bird is considered blue and not self blue, because of it's genetics. If it was the lavender/self blue genes modifying the black, the red would also be diluted.
Lavender can also be used in making secondary color patterns. Birds that are laced and carry lavender are referred to as violet laced. Even though the violet laced bird carries two lavender genes the buff or silver found in the bird disqualifies the birds from being a self blue.
Violet Laced birds are Silver Laced with the Blue gene, not the lavender/self blue. The lavender/self blue lacing is commonly call Lilac laced. Color patterns that use Lavender/self blue include Coronation, Isabella, and Porcelain Mille Fleur.