What’s a mixed absorbency surface?
It’s a great surface you can easily make yourself, to get interesting painting effects and texture right away, regardless of which painting medium you use! Read on to find out how to use this with your creative work!

To start a painting, a painter will usually begin with some commercially prepared substrate; such as watercolor paper, cardboard, primed canvas or primed panel. From there you simply start applying paint. No problem with this process! It’s quick and easy. BUT you may be missing out on a fun and wonderful way to create interesting effects, and save money, all from adding one simple step before applying paint.

Compare this image, using diluted paint on board with gesso

with this image, using the same diluted paint but on a on mixed absorbency surface

Here is a photo of the mixed absorbency surface before applying paint

How to create a mixed absorbency surface.
1. Starting with any substrate, follow any necessary procedures required for painting. For example, watercolor paper needs no preparation but can be primed with gesso to add strength. Cardboard, canvas and wood panels do not need any preparation if they are already sealed and primed. If the substrates are raw with no sealer or primer they will need some preparation. Apply a stain sealer and primer if acrylic paint will be used for overpainting. Skip the stain sealer but still prime if oil paint or other mediums will be used. Let dry.

2. Apply acrylic binders (mediums, gels and pastes) onto your substrate to customize your surface absorbency.
Let’s look into this further. Every substrate has its own unique quality of absorbency. A high quality piece of watercolor paper is very absorbent. This means it has lots of tooth, or places where diluted paint can sink into which creates an even layer of color. Absorbent surfaces are always matte, which is one way you can tell if a surface is absorbent or not. Touch an absorbent surface and it will feel slightly rough because of its tooth. Something glossy, on the other hand, like Yupo paper, glass or metal, is non-absorbent. This means there isn’t much (if any) tooth. Diluted paint applied over a glossy surface will bead up and create an uneven layer of color, sometimes looking marbleized or puddled.

In the same way that substrates will each have a particular absorbency or non-absorbency, acrylic binders come in a wide variety of forms, also offering a variety of absorbent and non-absorbent qualities. Acrylic binders come in three different forms: mediums, gels and pastes. There are many choices in each of these three categories, and this can sometimes get confusing. Just remember that every product, when applied to your painting surface and left to dry, will create a unique surface quality and absorbency. And just about ANY acrylic product applied onto your substrate will present a more interesting surface to paint on then using the plain old substrate as is.

3. How to choose which binders to use.
Mediums are generally pourable and fluid, gels are thicker and create texture, pastes are also thick and create texture. So if you wanted texture you would choose gels or pastes, while mediums will offer a smoother layer. As I mentioned before, each product also creates a different absorbency. Gloss mediums and gloss gels create non-absorbent areas on a surface, matte mediums and matte gels create a semi-absorbent area, and most pastes (except for Molding Paste) create an absorbent surface area.

4. How to apply the binders.
To make your own custom surface, start by choosing one product. Apply it at least 1/4″ thick as acrylic will shrink down in volume while drying by about 30%. If you don’t apply enough of the product, by the time it dries you will not have a layer that is substantial enough to change the surface absorbency. I like to apply the products with a knife so I can apply enough product. You can add texture or keep it as smooth as your tool and product allow. Let this dry at least one day.

5. How to overpaint the custom surface.
Once your surface is dry, you can now overpaint it with paint. Appropriately dilute your paint (water for watercolor, water for acrylic, solvent for oil, etc) and apply these “washes” or diluted mixtures over the dry custom surface. You can spray water over the surface or apply water in areas to allow washes to “bleed” or run into each other. On absorbent surfaces, the washes stay wet for awhile due to the large amount of water in the mixtures. This means you can keep applying paint, as well as easily remove paint. On non-absorbent surfaces it is best to add lots of water to the surface to create a puddle, apply paint quickly leaving it alone to dry into interesting puddles.

Left: Washes on gessoed surface
Center: Washes on a mixed absorbency surface
Right: The mixed absorbency surface before paint was applied

6. Mixed absorbency surfaces.
Once you master making a custom surface using only one product, try making a mixed surface by using three or more products. Pick an absorbent, a non-absorbent and a product somewhere in the middle. Apply all over the substrate, overlapping if you wish, so that the end result is a surface with a variety of absorbencies. Once dry, apply diluted paint over the surface to see how quickly the surface encourages all kinds of effects.

You save money because with this process you use very little paint (since it is very diluted).

7. My favorite mixed surface.
My favorite combination of products to use for a mixed surface is as follows:
First I apply Light Molding Paste in a few areas. This is my favorite absorbent paste, note this is NOT Molding Paste, but is a very different product by Golden called LIGHT Molding Paste. Other absorbent pastes I like are Coarse Molding Paste and Pastel Ground. After applying one or more of these absorbent ones, I can continue to apply other products while still wet if I wish. So next I apply some mid-absorbency products, filling in whatever areas are still uncovered, using products such as Glass Bead Gel, Molding Paste and Heavy Gel Matte. As a last step I apply the non-absorbent products. Anything that dries glossy will work. Whereve I apply gloss, it will act as a resist. When I apply a wash of color of the entire surface, the paint will resist off the gloss, revealing the white surface underneath. I create gloss lines (which will end up being white lines after painting) using Gloss Medium squeezed out of bottles. I create gloss areas (which will result in white areas after painting) using Regular or Soft Gloss Gels, and apply them wet over the still wet mixed surface I am working on. In other words you can apply multiple products in one session while all are still wet. You do not need to wait for one product to dry to add another. But you do need to let the products all dry on the surface for at least one day before using it to overpaint with the diluted paint.

Nancy Reyner, painter, author and instructor offers assistance to artists in a variety of ways. Click here for more info.