Things that Can Go Wrong in Oil Painting

While oil painting is a generally forgiving medium, there are still things that can go wrong and mess up your painting if you were not aware of them.

Fortunately, you can easily avoid the most common mistakes if you work by certain guidelines. Better yet, some mistakes can be corrected.

When assessing the quality of a completed oil painting, the hardest part is that it takes some time before it properly dries, after which the damage can become manifest.

In other words, after enough time has been allowed for the painting to dry and at times even longer, cracking or drying out of the color mat happen. However, in majority of cases, the cause is easy to identify.

Oiling out

This is one of the most destructive effects of poor oil painting that happens very frequently, resulting from the sinking of the top layer. This is in turn caused by the rapid evaporation of the oil in the color, causing the layer to sink into the one below.

If your painting has spots of dullness after it has completely dried out, or its overall appearance is dull, then it needs ‘oiling out’. Besides making your painting susceptible to cracking, it also makes the painting’s finish uneven and blotchy.

This dull finish is mainly as a result of a wrong ratio of drying oils to solvents and paint. Precisely, it will occur when the concentration of the solvent is too high in the paint. For the early layers, this may be fine but for the top layer, it leads to a dull effect. An overly-absorbing surface is another common cause. Ensure that the painting surface you use is well primed so that the paint does not easily sink into a porous surface.

The good news is that you can use ‘oiling out’ to regain your surface’s sheen. In this process, an all-purpose medium, such as linseed oil mixed with 50 percent mineral spirit, is rubbed into the dull spots.

Use a soft piece of cloth to gently rub in the oil mixture, cleaning away any excess. When you apply varnish on its own minus the oil, you’ll solve the issue. You may apply it after oiling out and letting the painting dry thoroughly.

Cracking

When a top layer of paint is much drier than the one beneath it, it will usually result into a cracking effect on the painting. If the top layer dries faster and the bottom layer dries at a much slower pace, the top layer will crack due to the brittleness that results.

This kind of problem in an oil painting cannot really be repaired. If you apply another medium or more paint, you only make it worse. Therefore, it is better to prevent cracking from the beginning.

The simplest way to ensure your painting dries at a uniform pace is to use the right mediums and layer in the correct order. Oil painters use a traditional rule known as ‘Fat over Lean’. Put differently, you should increase the proportion of medium used in each layer when you’re painting in layers. Here’s an example:

First Layer – Very Dry; less color more solvents.

Second Layer – Dry; more solvents, more color.

Third Layer – Medium; less solvents, a bit of drying oil and some color.

Fourth Layer – Oily; color, drying oil, little or no solvents.

Stress

When you use too many different types of medium, you put the painting under ‘stress’. In this case, it’s not easy to predict the damage. You can easily mitigate against this problem by using the ‘Fat over Lean’ method. Use the same type of drying oil and solvent in each layer. If the mediums you’re using are ready-made, don’t mix them with others; only do so with solvents if you have to.