How to Mull Acrylic Paints Efficiently (And With Little Mess)

Updated on October 19, 2019
jbosh1972 profile image

I like to work with acrylic paint because it dries quickly and there are many colors and substrates available.

Quickly Prepare Acrylic Paint on the Slab

Many pigments, especially organic pigments, are hydrophobic and are difficult to disperse into water-based paint mediums like acrylic emulsion. The method of paint preparation that I outline consists of the following steps:

  1. Weigh out the desired amount of your dry pigment onto the glass slab.
  2. Apply a wetting agent and water to get a uniform slurry mix.
  3. Stir to work out as many lumps and larger agglomerations as possible.
  4. Put the smooth but somewhat gritty pigment dispersion into a small cup—but leave a 1 gram or so portion on the glass slab.
  5. Use the glass muller to grind the smaller agglomerations of the pigment dispersion until smooth.
  6. Set the fully dispersed pigment into a slightly larger cup and repeat with another 1 gram portion of gritty dispersion until all pigments are smoothly disperse.
  7. Add a few drops of clear ammonia to pigment dispersion just until it has a slight ammonia smell. This indicates an alkaline pH.
  8. Add sufficient acrylic medium to the muller pigment and stir until uniform.

Tools and Materials

These are the items needed to embark on the acrylic paint-making journey:

  • Two metal paint spatulas
  • A dry pigment of your choosing
  • Distilled water
  • Orotan 731K or similar wetting and dispersant
  • Clear and non-sudsy ammonia
  • Acrylic emulsion of your choosing
  • Prepared glass plate
  • Large glass muller
  • Small disposable cups for storing and mixing
  • A cheap roll of paper towels, rags, or torn t-shirts
  • 91% isopropyl rubbing alcohol

Weighing Out Approximately 1 Gram of Pigment Red 254
Weighing Out Approximately 1 Gram of Pigment Red 254 | Source

Weigh Out Dry Pigment to Make Dispersion

Once all tools and materials are gathered, it is time to weigh out the amount of dry pigment you will be using. This is the beauty of preparing paint, you only use what you need. Keeping that in mind, I’d recommend a 1 or 2 gram portion of dry pigment. That should be enough for swatch testing and trying it out on a small project.

To the mound of dry pigment in the glass slab, add a few drops of Orotan 731K and enough distilled water to make a liquid of salad dressing consistency. If pigment resist wetting add denatured or rubbing alcohol to assist in pigment wetting.

Orotan 731K for Wetting and Dispersing Hydrophobic Pigments
Orotan 731K for Wetting and Dispersing Hydrophobic Pigments | Source
Wetting and Mixing Pigment With Water
Wetting and Mixing Pigment With Water | Source

Wetting and Dispersing Dry Pigment

The ease at which a pigment wets and disperses depends on whether you have an inorganic or organic pigment. Inorganic pigments have larger particle, less surface area, and are usually water loving or hydrophilic. This makes them easy to disperse just with water and acrylic emulsion but a small amount of Orotan 731 K or similar surfactant mix will make breaking up agglomerations smoother.

With an organic pigment like pyrrole red, a significant amount of dispersion aid will be necessary. Sometimes you might want to add denatured ethyl alcohol or isopropyl rubbing alcohol to help wet the pigment. Both alcohols evaporate pretty quickly so that should not affect the end product. Just make sure the alcoholis gone before adding the acrylic medium.

Mulling to brake agglomerations in pigment dispersion
Mulling to brake agglomerations in pigment dispersion | Source

Disperse with Glass Muller

After thorough wetting and mixing the pigment with a painting knife, it’s time to mull the pigment into a dispersion . Using the glass muller, make circular motions changing directions frequently. A few figure 8 patterns will also help add shear force to break up agglomerations. The breaking down of agglomerations will be observed as gritty grinding noises.

Pigment Dispersion Complete after about 4 Mulling Cycles
Pigment Dispersion Complete after about 4 Mulling Cycles | Source

Add Acrylic Medium

After all agglomerations have been removed from the dispersion, use the pallet knife to add an equal volume of acrylic medium to pigment mound. Stir well until well mixed and all whiteness from acrylic medium is gone. Take a tiny drop and spread on some scrap paper. Look for any speckles or granules in the streaks. If needed mull the paint. But be mindful that acrylic dries quickly and you might end up mulling dried paint into your final product. Do not mull more than 10 minutes to avoid this pitfall.

Adding Acrylic Medium
Adding Acrylic Medium | Source
Stir with Paint Knife.  Your paint is ready!
Stir with Paint Knife. Your paint is ready! | Source

Test By Making Paint Swatches

Paint a full mass-tone swatch on a top corner of sketch bookamd label with pigment name and color Index number if you know it. For example, pyrrole red is ”Pigment Red # 254”. Write that down in case you need to cross reference later. Also make notes of portions or characteristics of the paint to help you with future experimentation.

Then put some water on the brush and rub the remaining paint on other side of sketchbook page to see if pigment is fully dispers.

Paint Swatches in Sketch Book
Paint Swatches in Sketch Book | Source

The Clean Up

If you followed through and did not deviate from the process, you should have a dirty spot on your glass plate only slightly larger than the diameter of the muller. The muller should be easy to clean since you have extracted most of the paint from it. Most of the paint on the spatulas will scrape off with old newspapers or junk mail.

  1. Take a rag or paper towel. Squirt some 91% isopropyl rubbing alcohol on it and clean the spatulas. This should take less than 30 seconds.
  2. Next, squirt some rubbing alcohol onto the pigment stain on the glass plate. Let it soak in for 2 minutes.
  3. Move on to the muller and squirt it with alcohol as you wipe it with your rags. It should come right off. Once all remaining color is removed off the muller, we now move to the glass plate. It’s been soaking in alcohol because it is ever so slightly more difficult to clean.
  4. Start wiping up the alcohol and partially dissolved paint. Pick up what you can in first attempt. Use a clean rag or paper towel and fresh alcohol to make sure all color is removed.
  5. That’s it! Clean up should take less than 10 minutes! This is a critical timesaver if you are preparing a few different colors.

Questions & Answers


      0 of 8192 characters used
      Post Comment
      • jbosh1972 profile imageAUTHOR


        6 months ago from Indianapolis, IN. USA

        Orotan 731 K is great stuff. For the difficult to wet organic pigments, I still use a dash of denatured or isopropyl alcohol to get started. I usually have to mull the pigment dispersion several times before adding the acrylic medium anyways. So most alcohol is gone by that point. Orotan actually adheres to the pigment particles so they stay dispersed.

      • profile image


        6 months ago

        Thanks Jason! That is very good information. I found your post when searching for Orotan 731 K, as I ordered some recently from Kremer Pigmente to make watercolor paints, using Aquazol as the binder.


      This website uses cookies

      As a user in the EEA, your approval is needed on a few things. To provide a better website experience, uses cookies (and other similar technologies) and may collect, process, and share personal data. Please choose which areas of our service you consent to our doing so.

      For more information on managing or withdrawing consents and how we handle data, visit our Privacy Policy at:

      Show Details
      HubPages Device IDThis is used to identify particular browsers or devices when the access the service, and is used for security reasons.
      LoginThis is necessary to sign in to the HubPages Service.
      Google RecaptchaThis is used to prevent bots and spam. (Privacy Policy)
      AkismetThis is used to detect comment spam. (Privacy Policy)
      HubPages Google AnalyticsThis is used to provide data on traffic to our website, all personally identifyable data is anonymized. (Privacy Policy)
      HubPages Traffic PixelThis is used to collect data on traffic to articles and other pages on our site. Unless you are signed in to a HubPages account, all personally identifiable information is anonymized.
      Amazon Web ServicesThis is a cloud services platform that we used to host our service. (Privacy Policy)
      CloudflareThis is a cloud CDN service that we use to efficiently deliver files required for our service to operate such as javascript, cascading style sheets, images, and videos. (Privacy Policy)
      Google Hosted LibrariesJavascript software libraries such as jQuery are loaded at endpoints on the or domains, for performance and efficiency reasons. (Privacy Policy)
      Google Custom SearchThis is feature allows you to search the site. (Privacy Policy)
      Google MapsSome articles have Google Maps embedded in them. (Privacy Policy)
      Google ChartsThis is used to display charts and graphs on articles and the author center. (Privacy Policy)
      Google AdSense Host APIThis service allows you to sign up for or associate a Google AdSense account with HubPages, so that you can earn money from ads on your articles. No data is shared unless you engage with this feature. (Privacy Policy)
      Google YouTubeSome articles have YouTube videos embedded in them. (Privacy Policy)
      VimeoSome articles have Vimeo videos embedded in them. (Privacy Policy)
      PaypalThis is used for a registered author who enrolls in the HubPages Earnings program and requests to be paid via PayPal. No data is shared with Paypal unless you engage with this feature. (Privacy Policy)
      Facebook LoginYou can use this to streamline signing up for, or signing in to your Hubpages account. No data is shared with Facebook unless you engage with this feature. (Privacy Policy)
      MavenThis supports the Maven widget and search functionality. (Privacy Policy)
      Google AdSenseThis is an ad network. (Privacy Policy)
      Google DoubleClickGoogle provides ad serving technology and runs an ad network. (Privacy Policy)
      Index ExchangeThis is an ad network. (Privacy Policy)
      SovrnThis is an ad network. (Privacy Policy)
      Facebook AdsThis is an ad network. (Privacy Policy)
      Amazon Unified Ad MarketplaceThis is an ad network. (Privacy Policy)
      AppNexusThis is an ad network. (Privacy Policy)
      OpenxThis is an ad network. (Privacy Policy)
      Rubicon ProjectThis is an ad network. (Privacy Policy)
      TripleLiftThis is an ad network. (Privacy Policy)
      Say MediaWe partner with Say Media to deliver ad campaigns on our sites. (Privacy Policy)
      Remarketing PixelsWe may use remarketing pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to advertise the HubPages Service to people that have visited our sites.
      Conversion Tracking PixelsWe may use conversion tracking pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to identify when an advertisement has successfully resulted in the desired action, such as signing up for the HubPages Service or publishing an article on the HubPages Service.
      Author Google AnalyticsThis is used to provide traffic data and reports to the authors of articles on the HubPages Service. (Privacy Policy)
      ComscoreComScore is a media measurement and analytics company providing marketing data and analytics to enterprises, media and advertising agencies, and publishers. Non-consent will result in ComScore only processing obfuscated personal data. (Privacy Policy)
      Amazon Tracking PixelSome articles display amazon products as part of the Amazon Affiliate program, this pixel provides traffic statistics for those products (Privacy Policy)
      ClickscoThis is a data management platform studying reader behavior (Privacy Policy)