Thursday, February 25, 2010

What causes oil paint to crack?

I'm working on an oil painting. I paint in the garage, it's summer, and I live in Florida, so it usually gets hot in there, so I get a fan. I've noticed some cracks in the paint, lately. Why is that? Does it have to do with the heat or with the air from the fan? Should I take the painting in after painting so that it's not exposed to the heat? Also, I've noticed the cracks on mostly the parts that have burnt umber. Do the cracks have to do with the color of the oil paints?What causes oil paint to crack?
Burnt umber can be susceptible to cracking. The quality of the paint is a factor however iit is renowned for what is called ';sinking in'; whereby the paint dries to a dull finish while other areas painted with different colors will retain the more glossy finish. This is a problem because it becomes difficult to match colors on subsequent layers. The matte finish alters the color so the fresh wet paint will never match and you must either make a guess or you have to revive the sunk in areas with retouch varnish (the best way of dealing with this).





Cracking can be caused by using too much drier in a medium or it can be caused by a poor foundation. The underlayers may contain too much oil or are thicker than subsequent layers. The underlayers change physical composition and it is like an earthquake. The top layers can only accommodate a limited amount of change to its foundation.





Fat over lean is a principle to adhere to. The lowest layers are thinner and contain less oil. The subsequent layers are think with more oil. This allows the lower layers to dry faster so the subsequent layers have a settled foundation to dry upon.





In your environment the heat and humidity effect the drying more than the direct heat and moisture factors into the cracking you are seeing. Mold would be an issue in time.





The Old Holland brand of Burnt Umber is the least prone to sinking in and cracking. Follow the fat over lean rule. Try to use less Burnt Umber and mix other colors into it. Store your work in a cooler, drier, stable area and out of direct sunlight. All of this will help with these issues.





https://www.aswexpress.com/art-supply/ca鈥?/a>What causes oil paint to crack?
You had an extended answer on top but I can tell you that if you paint from fat thin, no matter how hot or humid your paint will crack. I paint in the style of impasto and like to use my paint out of the tube because I like it thick. When drying between layers in the summer I put my painting in the garage when it gets really really hot. I live in Texas and the summer is usually between 90 to 110 degrees.





I am not sure how you are painting, but I paint in layers. Your base paint should be thinner and only use mineral spirits, then as you built and let dry you can use other mediums such as linseed oil. If you use linseed oil in your under paint with time it will crack.





I would never recommend painting wet on wet unless your layers are very thin.
If for any reason, there is moisture on top of the paint, it would definitely crack.





Dramatic change of temperature too
the oils in the paint dry out and cause it to crack over a period of time plus moving them and Temperature change
  • ie tab
  • No comments:

    Post a Comment