The Waving Flag: Painting Tips #5b - Matting Acrylics With Talc

Thursday 1 May 2014

Painting Tips #5b - Matting Acrylics With Talc

This week picked up the first article in this series and I've experienced a spike in site visits. I don't know why they decided to feature a three year old post but feature it they did and I'm grateful for the plug. As the original article was written in 2011 I decided to write a brief update.

In the three years since my first post I've continued to matt my paints with talc and haven't really deviated much from the method I developed in the first 5 or 6 months.

I now add a touch of talc to most of my paints. You soon learn which paints need talc and which don't. I really like the way adding talc removes any insecurities about varnishing and I find the flat paint finish really helps as I can see the highlights that much better.

I'm also pleased to say that I've not seen any changes in paint adhesion at all, which is a big plus.

Whilst adding talc solved all my problems I was still puzzled why I had a problem to begin with. It didn't make sense that certain "untalced" colours gave a satin finish after varnishing even if the paint was perfectly flat before varnishing and further coats of varnish had no effect whatsoever. It wasn't just frustrating, it didn't make sense

I did a bit of research and found that the addition of talc doesn't just produce a flat paint surface. As the paint dries the talc particles, which are flat platelets, align with one another creating a barrier that cannot be penetrated by my prefererd spirit based varnish. To my surprise I found it was this "sealant" effect that solves the varnish problem not the visible matting effect.

With problem paints, like "untalced" reds and red/browns, the varnish penetrates the paint layer and the matting effect of the varnish is lost. As varnishing does not seal the paint, further coats of varnish have no effect either. The addition of talc ensures the paint is sealed and any varnish forms a discrete surface layer during drying and works as designed.

Perhaps it's just me, but I feel so much better having solved a problem and found out why it works!

If you would like to know about varnish try my article from Minitaure Wargames "The Unvarnished Truth" available on my articles page.


Tony said...

I hadn't seen this post the first time around and am therefore grateful that Miniature Wargaming re-posted it. As you know, I have both commented and re-posted on my own Blog and the reaction has been surprising.

Once again thanks for the original post and this update.


Hands said...

Martin, I've added talc to a dark grey Vallejo color to test. While I can't seem to add enough to the bottle to produce any semblance of a matte look on my test pallette, using the 2-3 brushfuls was sufficient for a test batch to dry matte.

However, when I went over it with both a straight and 1:1 thinned acrylic varnish, both still dried semi-satin.

Should I use more talc?

Thanks as always!

Vexillia said...

I've found "matting" a whole bottle a problem. You can add some but mixing becomes a problem. I add small amounts of talc by brush to paint on my palette as you've done.

Unfortunately, matting paint will not guarantee that the varnish coat will dry matt; as you've found out. Change your varnish or use "Flat Future".

Hands said...

This was my concern. I appreciate it sir, as always!

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