Sometimes I think people consider hand dyes and batiks to be the same, often hand dyes bleed like crazy. Some batiks do bleed but good quality reputable ones seldom do. ( Hoffman batiks and Bali are two that seldom do)
very saturated - deep colors sometimes have excess dye— reds, purples, deep blues. It’s easy to test & see. I use a lot of batiks and seldom find it necessary to prewash .