A lot depends on:
a) The effect that you’re trying to achieve +
b) The nature of the top layer of veneer on the plywood.

To start with part b)…..if the top ply is a heavily bleeding wood like tallow or some of the eucalypts, then it may be necessary to apply a primer to stop the tannin bleeding through the ink and discolouring it. This would be more apparent for white and other lighter colours. If you’re wanting to showcase the wood, then that could be quite tricky.

However, if your print is going to cover the whole area, then a primer would be a great idea.
In that case, we’d recommend using the Colormaker 3-in-1 primer or Gal Iron Primer, the latter having excellent tannin block properties.