There are several different finishes used on acoustic guitars these days.
How the finish on an acoustic guitar is applied also differs and is also an important part of the process.
But does the finish affect tone?
Short answer yes.
But to what extent?
The Different Types of Acoustic Guitar Finishes
To answer this question let’s take a look at the different finishes that are commonly used on acoustic guitars.
“French Polish” Shellac
This is used mostly on high-end classical guitars these days. This is a traditional process that is very labor intensive – you can’t use machines to spray it.
This is said to be the best for tone.
It’s not very durable though and prone to scratches.
Oil varnishes are more durable than Shellac but not as durable as the other types of finishes below.
This is traditionally the most common finish used on steel string acoustic guitars. It is very durable and resists scratching.
If it is applied too thickly it can crack but when applied well and not too thickly, this is still a very good finish for acoustic guitars.
This is still used by a lot of guitar manufacturers.
The new-ish finishes on the block (has been used for a while now) are polyester finishes.
Polyester finishes are more durable, more resistant to scratches and more environmentally friendly than the other types of finishes. They’re also typically better for changing temperatures and don’t turn yellow like laquers can.
Of course there are varying formulas for all of the above and how well the finish works will depend on how good the formula is (and how well it’s applied). So these are only general descriptions.
Gloss and Satin Finishes
You may also have heard the terms gloss finish and satin finish.
A gloss finish doesn’t refer to the material used for the finish but how the finish is ‘finished’. A gloss finish is well… glossier. You might think of it as shinier.
A gloss finish can enhance the look of a guitar, not because it’s shiny, but because it brings out the wood grain of the guitar more so than a non-gloss finish.
Some guitars are finished with a high gloss appearance and some with a semi-gloss.
Gloss finishes are also easier to clean.
A satin finish is more like a matte finish. It doesn’t bring out the brilliance of the wood as much and for this reason gloss finishes are usually more sought after and are usually on more high-end guitars. Satin finishes are often used on more low-end guitars – but this isn’t always the case.
Some prefer the look of a satin finish and others prefer gloss.
The Effect on Tone?
So how does all of this effect tone?
Which finish is best for tone?
The finish of a guitar can definitely affect its tone but it comes more down to how well the finish is applied rather than the actual finish used – perhaps with the exception of French Polish which is said to enhance the tone.
But there are durability/maintenance issues with French Polish so it’s not often used these days for practicality reasons.
But amongst the other finishes, I think it would be very difficult to notice any effect on tone if applied expertly.
Expert Application of Finishes
How thick the finish is will affect the tone. If it is finished too thickly, then it will likely effect the tone in a negative way.
So the skill is to be able to apply the finish so that it as thin as possible but still have it so that it’s durable.
Gloss or Satin
Will a gloss finish sound better than a sating finish?
In my opinion no – or at least not noticeably to the average human ear. A gloss finish over a satin finish is predominantly an aesthetic choice.
There a few main different types of finishes used on acoustic guitars – with various formulas of those finish materials.
In the opinion of the author, of the finish materials used on acoustic guitars, there isn’t one that is really noticeably better than another when it comes to tone.
But how well that finish is applied will affect tone positively or negatively.
The finish does however have an effect on the durability, scratchability, maintenance and appearance of a guitar.
If you want to see more of a discussion on this subject, check out the link below.