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Fat Over Lean Rule Explained

The fat over lean rule is a critical method of working to ensure your painting stands the test of time. This requires that each successive layer has slightly more oil, and therefore is more flexible but it will take longer to dry. Each time you begin a new layer you must be sure the earlier one is dry. You can fatten your paint in one of two ways: by pre-mixing recipes of Stand Oil and Sansodor to add to your paint or by mixing directly on your palette. If pre-mixing recipes, you should make at least three which reflect a shifting ratio, from 1-part Stand Oil to 3-part Sansodor, 1-part Stand Oil to 2-part Sansodor and, finally, a 1 to 1 ratio. These mixtures can be kept in tightly capped jars in your studio, labelled with the ratio inside, to use as you need them. Stand Oil is the oil of choice as it is non-yellowing but be sure not to use it in your first layer. Alternatively, you can add Stand Oil to your paint on your palette in an increasing ration as your layers increase. If you follow the fat over lean rule, your layers will be strong, less prone to cracking and have a better colour saturation.

Video Transcript
0:10    Hi There. Today I'd like to talk to you about the fat over lean rule. This requires each successive layer to be slighter fatter and more flexible than the previous one. In practice, this will mean that the upper most layers contain more medium and dry more slowly. Layering means applying fresh paint over a dry layer.

0:38    If you paint fairly thinly, you can do this more accurately by preparing jars with increasing ratios of Stand Oil to Sansodor. Stand Oil is polymerised to increase its' viscosity and binding strength. It's discreet, powerful and non-yellowing, because of this it performs the task very well. It can be introduced from the second layer onwards. By doing this, you will maintain the integrity of your painting.

1:15    An alternative to using pre-mixed jars, is fattening your colour by combining on the palette when laying out, thinning more in the lower layers if required. If you don’t want to reduce the consistency of your colour then an alternative method is to fatten your colour on the palette when laying out. Slightly more Stand Oil is folded in with each successive layer. If you follow the fat over lean rule you will get the best from your oil colour. Your layers will be strong, less prone to cracking and your painting will have a better colour saturation. Thanks for watching.