The Waving Flag: Painting Tips #4 - Gloss vs Matt Varnishes

Wednesday 4 February 2009

Painting Tips #4 - Gloss vs Matt Varnishes

The "gloss is tougher than matt" comment is a wargamers' urban myth that crops up every so often on various web sites.  In this post I’m going to look at some of the false logic behind this myth.

Firstly, for a given type of varnish, there is no noticeable difference in strength between the gloss and matt variants. They will be based on the same basic solvent / resin mix differing only in the presence of the matting agent which is a minor ingredient by weight.

So why are gloss varnishes ascribed near mythical levels of protection compared to matt varnishes? Well it’s caused by some false comparisons and misconceptions:
  • There is a difference in strength between a spirit based varnish and a water based varnish [1]. The resins will be significantly different due to the different solvents involved (spirit vs water) with the spirit based resins generally being the toughest.
  • Usually, multiple thin layers of varnish are better than single layers. So if you apply two coats of spirit based varnish (gloss then matt) you should not be surprised to find that two layers of varnish affords more protection than one.
As a result the common hobby method of gloss (spirit) then matt (water) will be a lot stronger than matt (water) alone for both reasons of spirit vs water and two coats vs one.

This confusion is compounded by the observation that matt varnished figures become shiny on prolonged use.  This is often ascribed to the “weak” matt varnish layer wearing off.  Whilst this is possible it is more likely to be due to the transfer of sebum from the skin during use.  The wax in the sebum will produce a nice shine and it will look like the matt varnish has worn off.

Behind this myth is some good news.  If you prime your figures properly and use a good spirit based matt varnish you can save time and money because you only need apply one coat of varnish.

[1] Since 2009, when this post was written, the strength of water based varnishes has improved to the point that it matches spirit based varnishes but I don't know if any of the new resins are in use in hobby products.  This point was made in my 2014 article.


Vexillia said...

This article continues to attract interest and feature in forum debates on The Miniatures Page:

[1] Choosing a varnish
[2] Varnish myths.

Vexillia said...

More articles:

[1] Testor's Dullcote & Gloss - TMP.
[2] Varish - Steve Dean forum.

The latter is a long thread but contains some very good points: just ignore the "my way is the only way" posts.

The point about gloss surfaces being more difficult to varnish, because of their greater surface tension, is well made.

Vexillia said...

Regarding the above point about the strengths spirit and water based varnishes, it's important to note that:

"Historically, solvent based products could dissolve a wider range of polymers some of which produced stronger varnishes. Whilst this may have been true twenty years ago great strides have been made in recent years. There are now water soluble acrylic polymers that are just as strong as their solvent soluble equivalents. This is certainly true in paint for the automotive industry: whether this has completely trickled down to hobby and art products is a moot point."

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