Art Answers - Recent questions and answers in Oil Painting

Answered: Is it safe to use oil paint on top of acrylic paint?

Mon, 07 Oct 2013 06:02:34 +0000

Yes, so long as the acrylic paint underneath has completely dried. Sometimes artists are surprised this is possible but acrylic is actually an excellent surface to use as a base for oil painting - many people who are surprised about this seem to overlook that most canvases and wood panels are primed with a gesso coating that is, essentially, an acrylic medium.

However, a very important point to consider when using oil paints over acrylic is whether the final painting will be varnished or left as-is with just the oil paint on top. If it is to be varnished, there are few (if any) options that would be available and safe to use that will be removable (for future cleaning purposes) and work safely with both oil and acrylic underneath. In that case, either don't varnish the painting on top of such oil embellishments or completely cover the painting in oil paint and allow it to completely dry before applying any coats of oil-friendly varnish.

Answered: What kind of surfaces can I use for oil painting?

Mon, 07 Oct 2013 05:54:50 +0000

So long as a surface is primed properly, oil paint can be used on just about any surface. However, for the sake of protecting the durabiity of the artwork and to avoid cracking or damage, the main kinds of surfaces artists have narrowed down to are panels of wood and stretched canvas. There are different types of wood and canvas to choose from but in all cases the surface has to be prepared primed, also called a "ground", and the most common type of ground is gesso.

The most common type of canvas cloth used for painting are linen and cotton, with linen having a finer texture which allows for finer details without the texture of the canvas affecting brush strokes. Most often when painting on canvas, the material is first stretched onto pieces of wood called "stretcher bars" and then given multiple coats of gesso as a primer. For added archiavility and durabiity, a glue-like medium is used in the initial coat before the gesso layers are added.

As for wood panels, common choices might be playwood, particleboard or fiberboard. You might as why not solid wood as an option? That's because when one side of a solid but thin piece of wood is prepared with a gesso ground, it keeps moisture from penetrating that side of the board, so in different humidity situations the other side of the board will stretch and shink unevenly from the front, causing warps and potential cracking. Pressed wood allows for moisture to "breath" through the wood more evenly and resists warping. There are, however, very specific kinds of solid wood board which can be used that resist warping - e.g. well-seasoned, quarter-sawn and air-dried woods, which also have matching grains front & back to help further minimize uneven warping, but their cost compared to pressed woods may be prohibitive.

Lastly, it is possible to use oil paint on metal surfaces such as copper or aluminum but much greater care needs to be taken when preparing those surfaces.

Answered: Can I speed up the drying time of oil paint?

Mon, 07 Oct 2013 05:31:59 +0000

For standard oil paints, the best way to ensure faster drying is to mix a touch of thinner (preferably mineral spirit which is similar to turpentine) and also painting in very thin layers. This would be a preferred way, for example, to do the very first underpainting layer. Also allow the painting to sit in a decently-lit space with good ventilation but don't put it in direct sublight as it may cause the oil in the paint to dry too quickly and crack the texture. Adding Liquin Impasto can also help with drying time without thinning the paint out very much, depending primarily on how much you add to the paint. Adding oil-based mediums adds to drying time so try to limit your use of such mediums if drying time is more important to you.

Normal oil paint drys within 3-12 days depending on the particular color, brand and thickness as well as how much and what type of medium is mixed with it. For the absolute fastest-drying oil paint, you can choose to use alkyd-based oils which dry very quickly (within 18-24 hours, with re-workability limited to the first 8 hours). To hasten the drying time even more, use Liquin Impasto as a medium to mix with alkyd-based oils. It's not uncommon to achieve dry-to-touch results with that kind of mixture within 12 hours so long as other conditions are optimal (sparing use of mineral spirits, minimal to no use of oil-based mixing mediums, a space with good ventilation and indirect sunlight).

Answered: What is alkyd oil paint?

Mon, 07 Oct 2013 05:21:06 +0000

Alkyd-based oils act like any other oil paints and can be mixed with typical oil mediums and thinned with typical thinners. The main difference is with drying time, accelerating the drying time of the paints dramatically, usually within 24 hours while still remaining workable within the initial 4-8 hours. They are also able to be safely varnished within 30 days rather than upwards of 6 months or longer with traditional oils.

Answered: Is it OK to use varnish as a medium in oil painting?

Mon, 07 Oct 2013 04:42:02 +0000

There are many ways to think about this and in the end it boils down to your intent for the painting or who you believe based on their own experience.

Technically, varnish (which is a form of resin) can be included with other mediums to help with specific painting goals - whether to assist in drying, thinning or glazing. However, for paintings intended for long-lasting presentation, it must be considered that including varnish as a medium will introduce an added risk of yellowing or discoloring as the painting ages in years as well as potentially making it more difficult to adequately clean a painting many years into the future - which usually involves removing the top layer varnish coats and re-vernishing. If too much varnish has been mixed into the paint layers below the top varnish layer then removal of that top layer for cleanign purposes introduces the risk of picking up and potentially destroying the paint underneath. Choice of the type of varnish also plays a role - it is better to use "soft" varnish as the top layer coat and reserve "hard" varnish for mixing into mediums sparingly.

If archivabiity and conservation are not of great concern for the painting, then using varnish as part of the medium mixtures is perfectly sound. The main concern for such a use in that case might be the drying sheen of the overall painting as paintings making use of a variety of mediums and paint dilution methods will end up with an inconsistent sheen on the final surface - some areas dull while other areas shiny. A final varnish coat is necessary to then even out the sheen across the whole paiting.

So, to conclude, if you paintings are intended for limited display (such as for commercial reproductions) and have little value for fine art display, art buyers, galleries, etc, then paint however you want with varnish as an added medium if you choose. If, however, the work must last many years and be put up for display and potentially need to be cleaned to maintain its conservation then be very sparing with your varnish usage and be sure to not use a medium mixture that only includes varnish. Always mix it with at least some drying oil so that when it binds with the oil as that paint layer dries, it will have little risk of being picked up during cleaning of any final/top varnish is removed many years later.

A common medium mixture that includes varnish is 2 parts varnish, 2 parts turpentine or mineral spirits and 3 parts stand oil. A small amount added to paint will assist in maintaining a smooth flow while a larger amount will help in creating a translucent glaze for color-tinting effects. An alternative to varnish which doesn't introduce as much tack (an also helps add bosy and texture to brush strokes) is Liquin Impasto, which also helps to aid in speeding up paint drying time as it is alkyd-based and helps create a similar glossy sheen to oil paints.

Answered: What does alla prima mean?

Mon, 07 Oct 2013 02:22:11 +0000

Alla Prima in Italian actually means "first attempt" and describes the process of finishing a painting while any lower layers are still wet. Usually this happens in a single sitting although it's possible to still be considered alla prima if the lower layers are still significantly "wet" before additional layers of paint are added. Although alla prima usually refers to oil painting, it can sometimes be in reference to fast painting methods in another medium like watercolor.

Answered: What's the best way to store oil paintings?

Sun, 06 Oct 2013 14:18:13 +0000

Always store in a dark dry & clean place.