I paint with Winton oil paints, and I usually 'work back' into a layer of paint after a couple of days, using a bit of white spirit to do so. How long do I have before the oil paint dries to the point that this is no longer possible?
There is no simple answer, it depends on many factors like the temperature of where you live, sun and wind exposure, the amount and type of oil, the thickness of the paint, the color pigment itself.
Obviously, the more you wait the harder it will be, but within a week should be fine. White spirit is not recommended it will attack and unsaturate the color, better use a painting medium. You also run the risk of violating lean over fat by using a variable quantity of white spirit.
There are also mediums that delay the drying time, but the easiest way is to use oil as a medium.
Winsor Newton has this fantastic guide to show the drying times of various available colors. Here is the info and the link to the full page with additional details.
In short, here is the range:
- Fast Drying Oil Colors (Around 2 days)
- Medium Drying Oil Colors (Around 5 days)
- Slow Drying Oil Colors (More than 5 days - up to around 12 days)
Working with oil color allows for a certain degree of flexibility while painting, as it takes longer to dry than other media. Should you want to alter your work days into a project, oil color allows for such changes to be made. Its malleable nature, in addition to the depth, purity, and vibrancy of pigment quality, makes oil color a favorite among some artists.
Familiarizing yourself with the properties of various oil colors and their drying rates will help you achieve the best results, in addition to avoiding cracking and other mishaps. Generally, oil colors become ‘touch-dry’ in thin films within two to 12 days, but different reactions of each pigment when mixed with oil results in varying drying times which will affect your work.
We’ve rounded up critical information about each of our key oil color ranges and the drying rates of various colors for your convenience. Read on and print out the charts when choosing your oil colors of choice for easy reference!
For specific color drying times, click here.
For additional tips on working with oil paints, click here.
Once the paint layer has become tacky it is no longer possible to work back into it. It is not advisable to use white spirit for painting in oils. Mineral spirits is better but even so it should never be used to re-activate oil paint that is partially dry. By adding more thinner to the paint you will be weakening the paint bonds and the paint will flake off.
If you need to work on an area after it is dry to touch you will need to re-paint that area. You can 'oil out' the area to give it a 'couch' to work on and then re-paint. When painting over the first layers you will also need to follow the 'fat over lean' rule, so add less mineral spirits and a little more oil with each layer.