How to thin acrylic paint without losing opacity – 4 Best Ways

Opcity is something that looks very attractive and natural in acrylic paintings but the most common issue faced by today’s artists is loss of opacity during thinning of acrylic paints. Is it possible to save the opacity by thinning the acrylic paints? Well, yes some techniques may help you do so. Let’s educate ourselves on these techniques.

This blog aims to provide a complete guide on how to thin acrylic paint without losing opacity. We will also cover some important questions at the end of the blog.

So let’s start!

Best Methods To Save The Opacity!
1. Using only water can be the best, cheapest and the safest way to maintain the opacity. But you cannot use it directly as it will effect the binder in the paint. To solve this problem, you have to put an isolation layer over the canvas before starting a paint layer. 

2. There is another method in which we have to apply some water over the canvas with a brush and then create a thin layer of any paint. Then we will paint with the hellp of brush normally without adding water in these layers. Well, the first layer will be lighter but the next layer will be darker. 

Thinning acrylic paint causes some loss of opacity but there are some solutions to get beneficial results while thinning acrylic paints. Using flow improvers, Using Acrylic mediums, The gradual addition of water, and acrylic retarders can help to save opacity.

Here are some techniques that may help you to achieve thinning acrylic paint without losing opacity:

  • The gradual addition of water
  • Using Acrylic mediums
  • Acrylic retarders
  • Flow improvers
Are you facing the issue of extra shines in the painting? If yes then read: Why your acrylic painting is shiny?

1. The gradual addition of water

Acrylic paint is a water-based paint so we can add water to it to thin the consistency of the paint. It is the easiest way to thin acrylic paint. Firstly add a small amount of water to the paint and mix it thoroughly. Add water according to the desired results and make sure not to add too much water at one time. The addition of water causes the loss of opacity but if you can manage to add a few drops of flow improver in water then you can save 90% opacity.

Create the first layer on the canvas, make it an isolation layer while thinning the paint with water, and then let the first layer dry and then create another layer. This method will help to increase the opacity as the first layer will absorb much water and help the second layer to maintain the opacity. Two thin layers will provide maximum strength of the color.

2. Using Acrylic mediums

Matte and Gloss are acrylic mediums that are specially manufactured to extend the paint volume. These two mediums help to maintain the opacity of the paint while offering different endings to enhance the artwork. They help the color to get strongly attached and in this way, the paint does not lose its color strength after the thinning process.

Do you know!
Varnishes are also available in Matte and Gloss Finish. Read about them: What are the best sealers for acrylic paintings?

3. Acrylic retarders

Acrylic retarders are specially designed to slow the drying process of the acrylic paint and give time to artistic to work more efficiently with the acrylic paint. It is made with propylene glycol.

Our Comments About Acrylic Retarders: 
Acrylic retarders does not help to improve the flow of the acrylic paints but they maintain the opacity of the paints and provide the thinnned acrylic paint with the same color strength. 

Acrylic retarders can help to control the paint’s consistency while the thinning process can reduce the loss of opacity. 

4. Flow Improvers

Flow improver is a type of medium that not only improves the flow but also maintains the opacity of the acrylic paints. In other words, flow improver acts as water but it keeps the molecules of the paint together to improve the flow but also helps us a lot to get high opacity.

If you want to gain good opacity with your acrylic paints, use a small amount of this magical medium in the acrylic paints and mix them very well before use. You can also add a few drops in the thinning water.

Our Comments About Flow Improver!
No doubt that flow improver works better then water to maintain the opcity level. If you have some budget then do invest to get a good brand's flow improver. 

Things to take care of before thinning acrylic paints?

Before thinking about the paint there are many aspects to consider for a good painting experience. The first one is that make sure your acrylic paint is of high quality because low-quality acrylic paint does not respond well during the dilution process. Secondly, work on a neat and dust-free surface.

 Third, collect all necessary materials and tools like water or acrylic mediums. Besides you should need to test the thinning process on the palette or separate surfaces to protect the surface from unexpected results on the main artwork. 

To save the opacity it is recommended to use thinning mediums that are specially manufactured for the thining purpose. Two mediums extend paint volume without losing the color intensity. The first one is matte and the second one is gloss acrylic medium.

These two mediums help to maintain the opacity of the paint with multiple endings to enhance the artwork. Moreover, the use of acrylic retarders is to slow the drying process of the paint but it also allows to bound the color strength together. So, mediums such as Matte, Glossy, Flow improvers, and acrylic retarders can save the opacity.

Can you thin 100% acrylic paint?

100% thinning means that the paint gets the same consistency as water. One thing is that the paint can be thinned up to 100% with special fluids and mediums such as paint thinners. As acrylic paints are water-based they can also be thinned by using only water but in that process, you will lose some opacity.

Can you thin acrylic paint with alcohol?

Yes, you can thin acrylic paint with alcohol But it is important to use the right alcohol to thin the paint. Isopropyl alcohol (rubbing alcohol) is mainly used to thin acrylic paint. You can use 20% amount of alcohol to dilute the paint. 

It is best to use alcohol in moderate amounts to avoid thinning down the paint so much. However, isopropyl alcohol dried fast due to the high evaporation process. In this way, acrylic paints dry even at a faster rate than normal.

What is the best way to thin acrylic paints?

The use of an acrylic medium is the best way to thin the acrylic paint. It is specially manufactured for thinning purposes. It maintains the opacity of the paint and provides different effects and finishes. Add a little amount of the acrylic medium onto your paint and then mix them.

You can add more medium until your desired need is not fulfilled but make sure not over-thin firstly test on another surface and then apply it on the artwork.


What is Opacity in acrylic painting? 

Opacity and transparency are different from each other because opacity means how much the color consistency of the paint is visible. While transparency means the paint is reflecting and light can pass through it.
Opacity is the measure of paint’s consistency, thickness, and saturation.

Can I use oil painting mediums to thin acrylic paints? 

Oil and acrylic paint both are famous mediums for art but it is mandatory to not mix acrylic paint with oil mediums. Oil mediums are designed for use with oil paints which is not good for acrylics. If you add them, they will create some issues such as cracking, uneven drying time, and poor adhesion. 

Final Words

At last, many possible mistakes cause the paint to lose its opacity. While thinning, four methods can help to maintain the opacity of the acrylic paints flow improvers, Acrylic mediums, The gradual addition of water, and acrylic retarders. By using these major things, you can thin the acrylic paint. The best way to thin the acrylic paint is by gradual addition of water with some quantity of flow improver.

If this blog is helpful to you then you can get a complete guide on acrylic painting through the menu or you can directly check a few of the blogs on acrylic painting here:

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