I recently spent the day at a local art fair in Sunnyside showing my work.  A lot of people came by and looked at my paintings and asked what medium I used.  I had some oils, a few watercolors, some pen and ink drawings and a few gouache paintings.  Without fail people got confused when I said the word “gouache”.  I tried my best to explain that gouache is opaque watercolor.  I said that I have found gouache to be a more accessible medium to paint with as you can cover mistakes and work a painting far longer than watercolors.  I said how I hate using liquid friskets and how white gouache allows me to add highlights back into a painting, something watercolor doesn’t.  I was met with a lot of blank stares.  Eventually I gave up and just said they were all watercolors, it was easier than trying to explain the differences.

Being the art nerd that I am I went home and looked up the real definition of gouache:

gouache (ɡwäSH,ɡo͞oˈäSH)
noun, noun: gouache
  1. a method of painting using opaque pigments ground in water and thickened with a gluelike substance.
    • opaque watercolor of the type used in gouache painting.
    • a picture painted using the gouache method.
      plural noun: gouaches
These days I have really moved away from watercolors and use gouache instead.  I prefer gouache so much so that I have replaced most of the pans in my sets with gouache.
The picture above is my beloved large set.  I took half the pans out and simplified the palette (that is a discussion for another day).  I then replaced the watercolor half pans with full pans of gouache.  I knew I wanted to use gouache in a way that I could rewet and use the dry paint, this was the best way I knew of.  It took some experimentation to find a good brand of gouache that would still be rich and workable when rewet, in the end I found the paints from  M. Graham to be both rich when used from the tube and when they were rewet.
I must admit I didn’t find out about gouache on my own.  Like most artists I learn from the work of others, in this case by the work of James Gurney.  If you have never seen his work or have never visited his site then you are doing yourself a disservice.  I think he is one of the greatest living artists of our time and he is just as good of a teacher.  His website is an endless vault of information about art, materials, techniques and so on.  I would urge any art lover to check it out.
For me, gouache is the ultimate medium since due to several factors:
1.  It is very transportable so there is never an excuse to not be able to paint.  I carry a small set of gouache everywhere I go and have done all sorts of quick plein airs and studies using them.
2.  Gouache more forgiving that watercolor.  You can always cover old mistakes with new paint.  This gives me a great deal of confidence in any painting, even something experimental, since I know I will be able to figure it out eventually.  I can’t say the same with watercolor where I have too often worked a painting beyond salvation while trying to make it better.
3.  Gouache dries matte and is very easy to photo.  This sounds like its not a big deal but as someone who loves gloss varnish but hates how hard it makes it to get a good photo of the painting it is a VERY big deal.
4.  Gouache is an old medium.  It has been used for hundreds of years even if it isn’t as widely known today.  Many many artists have used gouache including some of my favorites like Winslow Homer or Ernest Meissonier.
So I would urge any painter to give gouache a try.  If you are like me you might just find your newest favorite way to paint.