Fat Over Lean Rule: Master This Technique to Prevent Oil Paint Cracking

Fat Over Lean Rule: Master This Technique to Prevent Oil Paint Cracking

Oil painting is a beautiful yet technically demanding art form that requires both skill and high-quality materials. One of the most common challenges artists face is oil paint cracking, which can occur if the painting isn’t layered correctly. To avoid this, following the fat over lean rule is essential. This simple but critical rule ensures that each layer of paint dries evenly, preventing cracks from forming.

In this article, we’ll explore why oil paint cracks, how the fat over lean rule can prevent it, and offer practical tips to ensure your paintings stand the test of time.

Why Does Oil Paint Crack Over Time?

Oil paint cracking often happens when the upper layers dry too quickly while the lower layers are still curing. This can cause the top layer to pull apart and crack as the base continues to oxidize.

The fat over lean rule ensures that the drying process happens at a consistent rate, allowing each layer to settle without putting stress on the layer below. Beyond technique, material quality plays a huge role. Using low-quality paints that contain fillers and additives increases the likelihood of cracking. For example, paints with zinc white tend to become brittle and crack as they age.

Understanding the Fat Over Lean Rule

The fat over lean rule is crucial to ensuring that oil paintings dry properly and remain crack-free over time. Here's how the process works:

Lean Layers (Lower Layers)

The first layers of your painting should be lean—this means using less oil and more pigment. Lean layers dry more quickly, forming a stable foundation for the rest of the painting.

Fat Layers (Upper Layers)

As you build up the layers, you need to increase the oil content, making the layers fatter. These layers will dry more slowly, allowing the entire painting to dry evenly from the bottom up. This prevents the upper layers from cracking as the lower layers continue to cure.

Using high-quality materials like the P9 All natural Oil Paint Kit naturally supports the fat over lean rule. Our kit contains pure pigments and sun-thickened flaxseed oil, ensuring a stable and durable surface for your artwork.

Common Mistakes That Lead to Cracking

  1. Using Poor-Quality Paints: Low-quality paints often contain fillers that make them brittle. For instance, zinc white, found in cheaper paints, can cause cracking over time.
  2. Skipping the Fat Over Lean Rule: Failing to increase the oil content in each layer leads to uneven drying, resulting in cracks.
  3. Improper Surface Preparation: A poorly prepared canvas or surface can cause adhesion problems, making the paint more likely to crack or peel.
  4. Environmental Factors: Fluctuations in temperature and humidity can cause the paint to expand and contract, leading to cracks.

    Best Practices to Prevent Cracking

    To ensure your oil paintings remain crack-free and durable, follow these essential practices:

    • Use High-Quality Paints: Our P9 Artist Oil Paint Set offers non-toxic, vegan, and eco-friendly pigments, ensuring your artwork stays intact and vibrant for years.
    • Follow the Fat Over Lean Rule: Gradually increase the oil content in each subsequent layer to ensure even drying.
    • Prepare Your Surface Properly: Make sure your canvas or painting surface is well-primed and suited for oil painting to promote proper adhesion and reduce the risk of cracking.
    • Allow Proper Drying Time: Give each layer sufficient time to dry before applying the next one. This is crucial to preventing cracks and ensuring the longevity of your painting.

      Why Material Quality Matters

      At P9 Art Boutique, we believe that using eco-friendly, non-toxic materials is key to creating artwork that stands the test of time. Our P9 All Natural Oil Paint Kit includes 9 pigments sourced from natural minerals, combined with a traditional oil binder made from sun-thickened flaxseed oil. This ensures that your paint layers remain flexible, allowing you to follow the fat-over-lean rule effectively and prevent cracking.

      In addition, our Non-Toxic Oil Paint Set features a natural calcium drier, which accelerates the drying process without compromising the integrity of the paint. This eco-friendly drier helps your paintings dry evenly and reduces the likelihood of cracking, especially when working with thicker, oil-rich layers.

      By choosing P9 Art Boutique’s professional-grade oil paints, you can confidently apply advanced techniques like fat over lean, knowing that your materials are designed to ensure durability, flexibility, and safety.

      What happens if I don’t follow the fat-over-lean rule?

      If you skip the fat-over-lean rule, your upper layers of paint may dry faster than the lower layers. This creates tension and leads to cracking as the painting continues to cure.

      Can humidity cause oil paint to crack?

      Yes, fluctuating humidity can cause the paint to expand and contract, leading to cracks over time. It’s important to store your paintings in stable environments.

      How long should I let each layer of oil paint dry?

      The drying time depends on the thickness and oil content of each layer. Thinner, lean layers may take a few days to dry, while fatter, oil-rich layers can take weeks.

      Are zinc white paints safe for long-term durability?

      No, zinc white paints can become brittle and are more likely to crack over time. We recommend using titanium white for greater flexibility and durability in your paintings.

      Final Thoughts

      Mastering the fat over lean rule and using high-quality materials are essential for creating durable, crack-free oil paintings. With our All Natural Oil Paint Kits and Toxin Free Oil Paint Set you’ll have the best tools to bring your artistic vision to life while ensuring the longevity and beauty of your work.

      Explore our range of professional-grade products today at P9 Art Boutique.

      Back to blog

      Frequently Asked Questions (FAQ)

      Are handmade oil paints suitable for beginners?

      Yes, handmade oil paints are suitable for beginner artists, especially those interested in learning more about the paint-making process and controlling the quality of their materials. Making oil paint from scratch can help you better understand pigments, textures, and the chemistry of paint. For beginners, our P9 Artisan Oil Paint Kit is a perfect introduction, providing high-quality, non-toxic pigments and materials for a safe and rewarding experience.

      What materials do I need to make my own oil paints?

      To make your own oil paints, you'll need the following materials:

      • Pigments: Dry, finely ground powders in the colours of your choice.
      • Drying Oil: Linseed oil, walnut oil, or other natural oils to bind the pigments.
      • Palette Knife: For mixing the pigments with the oil.
      • Glass Muller and Grinding Plate: These tools help ensure the pigment is evenly dispersed into the oil for a smooth, professional-quality paint.
      • Paint Tubes: For storing your handmade paints.

      Our P9 Artisan Oil Paint Kit comes with nine high-quality natural, Earth and synthetic mineral pigments, along with a natural oil binder, perfect for those looking to make their own non-toxic oil paints.

      Please note:The mixing tools are not included in the kit.

      How do I store homemade oil paints?

      To keep your mixed oil paints fresh and maintain their quality, here are some effective storage methods:

      1. Airtight Aluminium Tubes: Transfer your mixed oil paints into airtight aluminium tubes to minimize air exposure. Fill the tube about three-quarters full, then flatten and fold the end using a putty knife. Pinch the end with pliers to seal it airtight. Properly sealed, your paint can last for weeks or even months.
      2. Refrigeration: Store your palette in the refrigerator to slow down drying. This method can keep your paint usable for several days to a week. Make sure to cover the palette with cling film or place it in an airtight container before refrigerating.
      3. Freezing: For longer storage, place your palette in the freezer. This can keep your paint fresh for several weeks. Before using the paint, let it warm up slightly to avoid condensation. This method is especially handy if you paint regularly.
      4. Cling Film: Cover your palette with cling film to reduce air exposure. This is a quick and easy way to keep your paint usable for a few days.
      5. Glass Jars: For longer storage, transfer your paint into small glass jars. Adding a few drops of clove oil can help prevent the paint from drying out too quickly. Ensure the jars are tightly sealed.
      6. Aluminium Foil: Scrape any leftover paint onto small squares of aluminium foil and fold it to create an airtight seal. This can preserve your paint for a few weeks. Label the foil with a smudge of the paint colour for easy identification.

      Using these methods will help you extend the life of your mixed oil paints, ensuring you get the most out of your materials.

      When were oil paints invented?

      Oil paints are believed to have been invented around the early 15th century, with Jan van Eyck, a Flemish painter, often credited for refining the medium. While oil paints may have existed before this, it was during the Northern Renaissance that their use became widespread. Van Eyck's use of linseed oil as a binder allowed for richer colours, smoother blending, and slower drying times, which changed the art world and led to the eventual dominance of oil paints in Europe.

      What did artists use before oil paint was invented?

      Before the invention of oil paint, artists primarily used egg tempera and encaustic (a wax-based paint) as their main painting mediums. Egg tempera, made from pigment mixed with egg yolk, was widely used in the Byzantine and Renaissance periods due to its fast drying properties and ability to produce fine detail. Encaustic paints, created with pigments suspended in hot beeswax, were commonly used in ancient Egypt for portraiture. These mediums offered longevity but lacked the flexibility and blendability of oil paints.

      Can oil paints be used for Alla Prima painting?

      Yes, oil paints are perfect for the Alla Prima or "wet-on-wet" technique. This method allows artists to apply layers of oil paint without waiting for the previous layers to dry, creating a more spontaneous and immediate painting style. Natural oil paints, like those found in our P9 Artisan Oil Paint Kit, are excellent for Alla Prima as they offer vibrant colours and smooth blending without toxic solvents, making them ideal for both beginners and professional artists.

      What are non-toxic oil paints?

      Non-toxic oil paints are made without harmful chemicals, heavy metals, or volatile organic compounds (VOCs) that are commonly found in traditional oil paints. Instead, they use natural pigments and binders like linseed or walnut oil, offering a safer alternative for artists and the environment. These paints are free from toxic additives like cadmium, lead, and cobalt, which can cause health issues over time. Non-toxic oil paints, such as those found in our P9 Artist Oil Paint Set, are perfect for art lovers, students, and professionals who prioritise safety while maintaining vibrant, high-quality results.

      Are natural oil paints better for the environment?

      Yes, natural oil paints are far better for the environment compared to synthetic oil paints. Traditional oil paints often contain toxic additives, stabilisers, and heavy metals that pose risks to both the artist and the environment. In contrast, natural oil paints use eco-friendly, non-toxic pigments and natural binders, reducing their environmental impact. Our P9 Artist Oil Paint Set is an excellent option for artists looking for vegan, non-toxic oil paints that are safe and sustainable.

      How to fix hardened oil paint?

      If your oil paint has hardened or become too thick to use, here are a few methods to fix it and restore its workability:

      • Add Linseed Oil or Other Paint Mediums: If the oil paint is just starting to dry out or has become thick, adding a few drops of linseed oil or a specialised oil painting medium can help rehydrate the paint and restore its creamy texture. Mix thoroughly using a palette knife until the paint is smooth again.
      • Use a Paint Thinner: For more stubbornly hardened paint, you can add a small amount of odourless mineral spirits, turpentine, or another non-toxic paint thinner to dissolve the dried portions. Be careful not to add too much, as it can make the paint too thin and affect its consistency.
      • Warm the Paint Gently: Slightly warming the hardened paint (by placing the tube in warm water or near a mild heat source) can soften it enough to mix more easily with a medium. Be careful not to overheat the paint, as this could damage the pigments.
      • Use a Palette Knife: If only the surface of the paint has hardened, you can scrape off the dried layer with a palette knife and use the softer paint underneath.

      If your oil paint has fully dried and hardened, it may not be salvageable. Oil paints naturally dry through oxidation, and if too much air has been exposed to the paint over time, it may have cured beyond repair. To avoid this, ensure your paint tubes are tightly sealed when not in use.