Two styles that share a toolbox
Horror tattooing is black and grey realism turned up: deep blacks, heavy contrast, gritty texture, portrait-grade rendering pointed at film icons, demons, skulls and gothic imagery. Surrealism uses much of the same realist toolbox but aims somewhere else entirely: dreamlike, impossible compositions, morphing figures, eyes where eyes shouldn't be, imagery that intrigues rather than frightens. The overlap is real, and 'dark surrealism' is its own recognised lane: nightmare imagery with dream logic.
The practical difference when booking: horror lives or dies on likeness and texture, so it wants an artist with portrait-calibre realism skills. Surrealism lives or dies on composition, so it wants an artist who designs strange, coherent images, not one who just renders well. Both are specialist lanes; a portfolio full of the exact flavour you want is the only credential that counts. One misconception worth killing early: good surrealism is not 'random weird stuff'. The best pieces are tightly composed and usually deeply personal.
These styles want scale, so plan like it
Horror and surreal work skews big: sleeves, leg pieces, back pieces. That changes the process. A sleeve is not a stack of separate appointments; it's one composition planned around your body's flow before any linework happens, with background texture, smoke, fog and negative space designed to tie the characters together. Piecemeal collecting first and hoping it connects later is how you end up paying an artist to solve a jigsaw you created.