I'm trying to add details to a model that will be 3D printed and I'm using a 4k alpha brush but it's too pixelated unless I use 10's of millions of polygons. Is that right?

ie with the back of Suzanne's head as a test, I've used a Multires modifier at Sculpt level 6 (2 million polygons), then 7 (8 million polygons), then 8 (32 million polygons).

[![enter image description here](https://i.stack.imgur.com/XrpBa.jpg)](https://i.stack.imgur.com/XrpBa.jpg)

Do I really need that many polygons to get the detail quality I'm after or am I missing something?

Thanks in advance.