My understanding is that blues are not selfs. In other words, if you breed blue to blue, you get black, blue (50%) and splash. The APA has misnamed Lavenders as "self-blues". The Lavender color does have a small range from silver to violet, but there is no mistaking that they are Lavender. At least if bred only within a line of Lavenders. The ones I have look almost metallic, that is in the sun you cannot mistake that they are Lavender, almost ghostlike.
The blues have a huge range from almost white with a little black "confetti" here and there, to almost blue-black.
You can see pictures of Lavenders on Backyard Poultry or just Google Lavender Orpingtons.
Some of the confusion comes in when Lavender Orpington color is compared to Lavender turkeys and other breeds. Yes, there is some scientific similarity and phenotype resemblance sometimes, but often not helpful.
Pat