celtic bull

big neilly

i want the shape of a bulls head on my back with the horns going across my shoulders but i want it to be a celtic knot design dont know how it will look anyone any ideas or views

Diceicle

I think I can imagine what you're on about, there are neo-tribal style tattoos that are sometimes in the shape of animals and your idea seems to be a nice take on it. I'm finding it hard to imagine how your idea would translate to a tattoo though.
Neo-tribal (being just black) makes it easier to identify the shape and the detail, where as a celtic knot design within the structure of the bulls head would have to be done as black and grey shading, which may (or may not as the case may be) leave you with a knotty, slightly bull shaped splodge on your back for the rest of your days.
The most solid piece of advice I could give would be to go to a recommended tattoo artist (look at the gallery thread on page 1) and negotiate a price with them to sketch up the tattoo, this could cost you around €50 but would be well worth it in the long run.

Star Lord

Either that or you could go for the old celtic style book of kells/old punt notes kind of design, but it would take a skilled artist with experience of proper celtic design a lot of effort to come up with this.