Beautiful finish is very important here at Goodall Guitars. I spend about three hours on every instrument, leveling, sanding with successively finer grit papers, and laboriously buffing till they look like glass. When the guitar left the shop it was absolutely perfect without any shrinkage or dimpling whatsoever. And, our instruments are left for plenty of time for the finish to cure. Depending on the species, wood has fairly deep pores that need to be filled will a special paste filler and sealer before the top coats are applied. It is normal for the filler to shrink down a tiny bit into these pores over time. And because our instruments have thin finish for great tone, the thinner the finish the more this miniscule shrinkage will show. The human eye can see that shrinkage if it is even one-half of one thousandth of an inch deep! Our finish will also let the wood telegraph through to the surface a bit over time. It shows especially on the top of the guitar because this finish is even thinner and because the top soft wood moves more than the body hardwood. This can be a good thing because if the instrument is not humidified properly it will show low humidity ‘puckering’ on the surface. Almost like a vampire had sucked the life out of the wood. Cracks and damage are sure to follow.
Folks are getting used to seeing mass produced guitars and other items coated with thick finish now days but vintage guitars had a great deal of this shrinkage.