Nancy’s Painting Blog

Acrylic Mediums, Gels & Pastes. What are they?

Acrylic is an amazing medium for fine art painters. It’s not just paint! Acrylic research and development has taken acrylic far beyond what any other medium, like oil or watercolor, can do.

When we compare acrylic to all the other available mediums for painters, it is like comparing the computer application of Photoshop to an old fashioned typewriter. We can type something in Photoshop, but this program can do so much more. Imagine only using Photoshop to type a letter! We would be missing out on the vast possibilities that Photoshop has to offer. It’s the same with acrylic. To approach acrylic as if we are painting with oil or watercolor would limit the broad range of its painting potential.

The video excerpt below is about Acrylic Binders. It is from my course The Complete Guide to Acrylic Painting. It is the ultimate acrylic painting course, using self-guided video instruction.

The main difference between acrylic and the other painting mediums is its wide range of binder options. All paint is made of two basic components: pigment (color) and binder (turns the pigment into a paintable form).

Binders are also referred to as a “vehicle” or “medium”. They transform the pigment particles into a wet form creating a substance we can use as paint. Acrylic or polymer is the binder for acrylic paints.

Ever find yourself standing in awe (and confusion) at the long row of products in the acrylic section at the art store? It can be mind-boggling! Yet almost all of these products can be divided into two main types: paints or binders. As I mentioned before, acrylic paint combines color pigment with acrylic binder. These are called paints because they have color! Binders represent the rest of those products, usually without color, and can be divided into three main types; mediums, gels and pastes.

Let’s look into the three types of binders more closely. The differences between them are mainly about consistency, transparency and drying times.

Consistency
Mediums are thin and pourable, smoothing the paint or surface. Gels and pastes are thick, adding texture to the paint or surface.

Transparency
Gels and Mediums can be purchased in different sheen types, such as gloss, matte and sometimes semi-gloss. Gloss versions applied over a paint layer or color, will be transparent like the Regular Gloss Gel pictured on the left in the image below. You can still see the black lines underneath the gel very well. Matte and semi-gloss versions applied over a paint layer or color will look translucent or slightly milky, as seen in the middle image. Pastes are opaque, and will cover over paint layers like the Molding Paste on the right side of the image.

Each type of binder, as well as each paint color, has its own quality in terms of transparency versus opacity. You can change and customize the transparency or opacity of paints by mixing them with binders. The more transparent a layer or color is, the more “see-through” it is, allowing an underlying color, image or surface underneath to show through. The more opaque a layer or color is, the more it will cover up whatever is underneath. Adding gloss mediums or gels to a paint color increases its transparency, adding pastes to paint colors increases its opacity.

Adding matte mediums or matte gels to paint creates translucency offering opportunities to replicate wax and other veiling effects. Adding more or less of each of the above creates varying degrees of transparency, translucency or opacity.

Let’s look at glazes as an example. Glazes are made by mixing very small amounts of paint color into mediums. Substitute gels for mediums in this scenario to make contemporary textural glazes.

As you can see from the images below, when mediums and gels become dry, they clear up quite a bit, to something either transparent or translucent, while the paste still remains white and opaque. A small swatch of matte medium and matte gel are applied to the bottom of their gloss counterparts in the photo, to show the translucent quality of matte products.

Drying Times
Another consideration between mediums, gels and pastes are their different drying times. Adding gels to your paints will increase the open time, another way to say that it will slow down the drying time. Pastes dry quickly so adding these to your paints will allow for those paints to dry faster too. There are also some mediums that are meant to dry extra slow and are mentioned below.

Here is a list of my favorite painting products for each category. These are mainly Golden products as that’s what I use in my studio.

Mediums
Mediums are usually thin enough to pour easily out of their containers. The gloss versions are white when wet, but dry totally clear. The matte versions dry somewhat semi-transparent. Mediums are pure polymer binder. Here are several choices I like to have around my studio at arm’s reach, with a list of how I use them.


Gloss Medium
Mix into paints to make them more transparent and/or glossy
Apply to a surface to seal it or make it glossy
Apply over paint to enhance colors

Matte Medium
Mix into paints to make them more transparent and/or matte
Apply to a surface to make it more matte
Apply over paint to veil or mute colors

Acrylic Glazing Liquid
Use as a slow drying medium
Mix into paints up to 40% to slow down the drying to apply a color evenly
Apply to surfaces to work wet-in-wet
Mix into paints over 40% to make colors more transparent – into a glaze

OPEN Medium
Use as a very slow drying medium, same as other mediums.
Add to paint to make color more transparent.
Can be used with the matching slow drying paint line called OPEN. Can also be mixed with regular acrylic paint lines.

Golden has a line of 7 specialty purpose mediums, called GAC’s. I will write a separate blog article on these soon, and when posted will add a link here. In the meantime, click here to read more about them on Golden’s website.

Gels
In general, Gels start out in manufacturing as thin mediums, but are put through a thickening process to stiffen their consistency. They are usually packaged in jars or tubes, and can be handled with knives or brushes. Like unthickened mediums, the gloss versions are white when wet, but dry totally clear. The matte versions dry somewhat semi-transparent. Gels are pure polymer binder. Here are several choices I like to have around my studio at arm’s reach, with a list of how I use them.

Soft Gel Gloss
Use for same reasons as gloss mediums, but when texture is desired
Create textural glazes by adding color
Add transparency by mixing into color
Slow down drying by mixing into color
Use to make an Isolation Coat to protect one layer from the next, usually used directly under the final varnish layer. Mix 1:1 with water
Great glue for paper and objects
Apply over white grounds in places to act as a resist

Regular Gel Gloss and Heavy Gel Gloss
can be used same as Soft Gel Gloss but are thicker

Soft Gel Matte
Use for same reasons as matte mediums, but when texture is desired
Create textural glazes by adding color
Add transparency by mixing into color
Can use as glue for paper and objects where you don’t want gloss
Apply over paint for veiling or muting colors

Regular Gel Matte and Heavy Gel Matte
can be used same as Soft Gel Matte but are thicker

Clear Tar Gel
Use for pouring purposes in thin layers. Only dilute with water in dry climates and minimally. Avoid diluting to create marbleized color effects.

Pastes
Pastes are made with polymer binder, like mediums and gels, however they have other ingredients added to make them thick and opaque. They are usually packaged in jars or tubes, and can be handled with knives or brushes. Here are several choices I like to have around my studio at arm’s reach, with a list of how I use them.

Light Molding Paste
Use as a white paint in mixtures to make tints but keeping colors bright
Add to paint to create fluffy absorbent textures
Apply to surfaces to increase surface absorbency
Apply as a “white-out” over painted areas you want to change completely
Add to paint to quicken its drying time

Coarse Molding Paste
Same uses as Light Molding Paste except it dries more transparent
Apply over painted areas to veil or mute

Molding Paste
Use in stencils for relief texture
Add to paint to thicken and make more opaque
Apply over surface to create smooth slightly non-absorbent surfaces

Special note: Additives such as retarder and flow release are not acrylic binders. These need to be used in correct proportions as described on their product labels.

Summary
All binders can be mixed together with other binders, with or without colored paint. They can also be layered one over the other in any order. Binders can be added into paints to customize your paint. They can be applied by themselves on a surface to customize your surface prior to painting, during painting and after painting. Wow, right?

This article excerpted from The Complete Guide to Acrylic Painting. It is the ultimate acrylic painting course, by Nancy Reyner using self-guided video instruction.

12 thoughts on “Acrylic Mediums, Gels & Pastes. What are they?

  1. Thank you Nancy this was so informative.

    I recently purchased your book and am excited to test all my new found knowledge. I enjoy all of your videos.

    Thanks, Liz

    PS. Linda McElvey from NC recommended you and your work.

    1. Hi Liz, I’m glad you found the article helpful. Enjoy my book and the new year!
      Thank you for your comments!
      Nancy

    1. Hi Bruce,
      Thank you for your interest in my books. I would be glad to send you e-book versions. Just email me back with what you want and I’ll send you a Paypal invoice. Ebook versions are half the retail price. Another idea – can you purchase on Amazon? All my books are available on Amazon. Let me know if I can be of further assistance.
      Nancy

  2. Thanks so much for sending the tips…a new book in the making??? And your new painting is just gorgeous with such an evocative title…a violet moon. I can feel the light of such a heavenly body; very very different.

    1. Thanks Nancy! No new book in the making…well at least so far…. The video in this post is from my course The Complete Guide to Acrylic Painting, which is a DIY video course. I think you saw parts of it during the Painting Excellence Class? Hope all is welll! Happy New Year!

  3. Thanks Nancy …….more concise information and such clarity and your clips are always so clear. Thank you for your generosity. Adore your painting…really something..so evocative.
    I just purchased your Complete Guide to Acrylic Painting. very excited.

    Happy New Year.

    1. Hi Crissea,
      Thank you for purchasing my acrylic course. I just sent you all the info to access your course materials. Let me know if you have any issues and I will gladly resolve it! Enjoy!
      Nancy

  4. Hi Nancy I am making an 6×9 collage with paper what is an inexpensive medium that will last? Someone suggested wheat paste to me.

    1. Wheat paste and other non-art and non-archival products will not last. You can add salt into the wheat paste to keep it from getting moldy, but ultimately, within a couple years the paste will flake off along with your collaged paper. Professional quality fine art mediums that are archival mean they will last for 500 years or more. That may not be one of your goals with your art, but if you are selling your work, giving it as a gift or other ways you want it to last then it is worthwhile to purchase a good quality medium. I like to use Golden’s Soft Gel Gloss for most of my glueing needs, including collage. Mediums have no pigments in them, which is what jacks up the cost of art supplies, and so you can easily purchase a small container for very little money. Hope this helps!

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