This lesson focuses on materials that you may mix in with your paint. Set aside the water and join me in the world of acrylic mediums!

In the following video, I walk through the usage of acrylic mediums and additives:

 

Acrylic Mediums

Acrylic mediums are probably as misunderstood as they are useful. Think of them as clear paint. Acrylic medium is in effect, the “medium” that is carrying the pigment in all of your tubes of acrylic paint – only without the colour!

There is a dizzying variety of choices designed for various applications, from thick plaster-like modeling pastes to fluid glazing and finishing mediums. The three most common uses are:

1. To add thickness for impasto effects: use Gel medium.
2. General painting – to help flow paint onto the canvas, marginally increase drying time and for better blending: use a general purpose painting medium.
3. Glazing and finishing – use a fluid medium, sometimes called “varnish”. Matt or gloss to suit your preference.

There is a mind-blowing variety of names on store shelves – “gel fluid satin glazing paste” is about the only one I have not seen – yet! The good news is that most have a summary description on the bottle, speaking to the uses in the above general categories. The following website has a good summary: https://www.art-is-fun.com/acrylic-mediums

Slowing the drying time

A useful characteristic of all mediums is that they somewhat slow the drying time, essentially because they are adding more paint substance that then needs time to dry.  Retarder is an additive that further slows drying.

Retarder is not a Medium

“Retarder” (even more confusingly called ”Medium Retarder” in French) is not to be confused with Medium. Retarder is an additive as opposed to a painting material. Retarder works chemically in your paint mix (with or without medium) to slow down the drying time. I’d try painting without retarder and introduce it should you have drying problems. Even with retarder, drying can be unpredictable and the real solution is to choose a slow-drying series of paints.

Slow drying medium

In my view, more useful than retarder is to use a slow-drying acrylic medium. The Golden “OPEN” series is probably the best known.

Glazing

Glazing is often sidelined as a painting technique, perhaps with a little mystique surrounding it. I use it fairly frequently and find it useful for integrating the paint surface, adjusting tone over a complete painting or just in part:

Glazing Tips:

1. Always have the canvas horizontal;
2. Use a good quality fluid medium, especially for final finishes;
3. A general purpose medium, diluted by say 30% water, works quite well in a pinch for passages in the middle of the painting process;
4. Tinted glazes are best completed with only a little paint in the mix, say 10%. Higher percentages of paint will yield more opaque results;
5. Use a large, soft, flat brush. I’ve glazed with a range of mid-priced synthetic brushes, typically 2″ wide. Don’t use a house paint brush as some are good quality, but being thicker, they soak up all your paint mix!
6. Gently squeeze out most of the water from your brush prior to commencing glazing – wet brushes can momentarily add water into the process with very unpredictable results;
7. Get plenty of your mix on quickly, spreading it out in all directions. Then, carefully brush horizontally and vertically in succession with an even stroke, from edge to edge – almost dragging the brush horizontally;
8. Once you’ve achieved an even sheen (perhaps with some brush marks still visible), resist the temptation to over work. Certainly, should any part of the glaze start to dry…STOP!
9. All glazes look better dry than wet…give it time to dry before you inspect your work;
10. Practice first on a test surface to check out the effects!

Exercises

1. On your next painting (perhaps following some initial layout), put the water pot to the side of your work space and paint entirely using medium rather than water. Notice that the paint flows better, blends more consistently and is generally more fun. Water is for clean-up!
2. Take an old painting or alternatively some swaths of paint on a flat surface and glaze a clear coat.
3. Follow this by taking the same mix and add 5% of a transparent pigment: Alizerin crimson, Ultramarine blue or Hansa yellow would be good choices – singly or in  combination. Perform a second glaze with your mix over part of the surface.
4. Finally try the same type of glaze with 5% opaque pigment: Burnt sienna, Yellow ochre, Cadmium (red or yellow) or Cerulean blue. Notice that the effect is less vibrant.