Acrylic versus oil painting techniques

Since I started out painting in acrylics and now I am reading up on painting in oils (WSOs), I am seeing a distinct difference in how people paint in each medium. So far, all of the books that I have used to teach myself painting with acrylics have seemed to use a very direct approach to painting - IOW, the artists don't sketch the outlines on the canvas first, they don't create an underpainting, and most of the layering is just used to get the different elements of the image on the painting in the right place. While I have seen demonstrations of glazing after most of the painting is done, it seems to only be done for certain effects and it doesn't seem to be the norm, at least not in the instructional books and videos.

Now that I am reading all about oil painting techniques and processes, it seems much more formal and complicated in comparison. Many start with a sketch of some kind on the canvas, then an underpainting is done, then there are all of these layers done, many of them for glazing on top of glazing - 2, 3, or even 4 layers of paint over the same area. It seems like a very laborious process, especially considering the drying time of oils, compared to what I was seeing in the acrylic painting "world" and I wonder why it is like this.

My questions are:

• What is the purpose of doing so many layers of paint?
  
• Why is there this big difference in process and technique between the 2?
  
• Is the difference due to the paint itself, or is it due to the different evolutionary paths that each medium has undergone over the years?
  
• Is alla prima painting not very popular in the oil painting "world"?
  
• How does an oil painter handle painting en plein air if they always go through this very lengthy process to create a painting?

I hope this makes sense. I am finding it hard to express myself this morning!

WOW! lots of questions. Hopefully, a lot of people will respond. A lot of artists do alla prima with oils. check out this link. https://watersolubleoils.forumotion.com/t149-any-tips-for-working-alla-prima?highlight=alla+prima

Plein air is pretty much alla prima with the exception that some people do finishing touches back in the studio. The key that artist follow still relates back to fat over lean.

Cindy, I've been painting with oils for about 4 years, so I'm not exactly an expert, but I can chip in with some comments.

There are many different techniques and working styles in oils.

Last weekend, I painted a small sketch on canvas. I had already drawn a pencil outline directly on the canvas in order to make sure I had the compositional elements in the right place.
Then I worked with thinned paint, alla prima style for the 2 hour session.
The next day, I touched up and added some paint here and there, using less thinner. The base was still wet, but I wanted the new paint to be a bit thicker.

Other times, I will work layer by layer. I will use thinned (lean) paint on the base, then come back to the painting a week or two later and continue. I will then use paint with less thinner, progressively adding a bit more medium to it (fatter). I have learned the hard way what it is like to see my paintings crack from not observing the 'fat over lean' rule.

It sometimes takes me a month or two to finish a painting, so I end up painting over dry paint a lot. Not because I want to, necessarily, just the way my schedule works. I just have to paint when I have the time. Plus, sometimes it is easier to paint hard edges on top of dried paint than on wet paint.

I have never used glazing medium, so can't make any comments on that technique.

But to summarize, I sometimes finish a small painting in one sitting, and my large paintings are always demand several sittings. Each demands a different approach.

The painting methods for acrylic or oils need be no more complicated than you are willing to make them. Glazing techniques can easily be transfered to acrylic painting as well, and there are tons of people who prefer direct application of paint when using oils. In fact, alla prima techniques began with oils.

The main reason for layering paint is to acheive a mix of color tones that one can't get from directly mixing the paints together on a palette. This comes from the transparency of the pigments themselves or a dry scumbling of the new layer. Obviously since this relates more to the pigment than the medium, one can glaze with acrylics also. In fact, I would say acrylics tend to lend themselves more easily to glazing by the way the medium works as a vehicle for the pigments, and the use of water is not as much an issue as it is with thinned oils. Acrylic medium is more of a glue than is an oil binder. Glazed layers of pigment, however, tend to have a more jewel-like appearance in oil than acrylics due to how light travels into the dry medium. Glazing with oils requires a sufficient drying time between layers so it lends itself to being done in a studio setting.

Oil paint layering is an old technique. Most of the early use of oil paint was essentially monochrome tones that were then colorized. It grew out of a tradition of using an egg tempera base that was then covered with thin layers of oil that allowed for easier blending and a stronger paint film. Eventually it became all oil paint, but they stuck with the same preliminary drawing and toning process for centuries. A more direct approach had been used for some time, but not for finished works, at least for the more academic schools of painting. It wasn't until the later part of the 19th centuy that a direct approach by itself for finished pieces became to get acceptance.

Why is there this big difference in process and technique between the 2?

There doesn't have to be a huge difference between the two. Many oil painters don't sketch on the canvas before they paint. It is usually done, if you want to get a realistic style. Alla Prima is more difficult to do with oil paints because the oil paints take so much longer to dry. If you add acrylic paint to a still wet layer of acrylic paint, the colors mix together and look like mud. The same thing is true with oil paints, but the oil takes longer to dry. Many oil painters have several paintings going at the same time, so that at least 1 painting is dry and can be painted on every day.
You might want to buy a tube of Cobra WMO along with your Holbein oils to check it out. The Cobras appear to be the fastest drying WMOs, in general. In fact, I would suggest that you try to order a few different brands to start with. I would just get a tube of red, yellow, blue and white, each in a different brand, to try out the different brands of paint and see which one you like best.
I think that the biggest difference between acrylics and oils is the use of medium. As Watermixableguy mentioned, it is important to have your bottom layers thin/lean (less oil), and the upper layers more thick/fat (more oil). The artisan thinner can be used with all brands of WMO and can be used on the first layers. Your brand of oil mediums can be used on upper layers. Also, you may want to try one of the quick-dry mediums, if you want the paint to dry faster. Don't use too much of the quick-dry or it will yellow your painting.
Hope this helps. Happy painting.
Dayle

Thank you, everyone, for your help explaining this to me. I must sound pretty dense to not get this on my own.


So I get that I could probably use the same methods I am using now with acrylics with the WSOs except that I will have to wait for them to dry if I want to paint on top of a layer. The most common time I do this is with the sky - I paint it in first, down as low as it will be seen, and then layer the other objects on top of it, be it mountains, trees, or whatever. I have seen some oil paint demonstrations were they don't do it this way - they paint the objects first and then paint the sky around them, rather than overlapping them. I guess this is necessary when doing alla prima (or almost alla prima) because it's the only solution if you don't want to wait on the sky to dry first. With the regular acrylics I have used so far and being in a dry climate, I only have to wait 10-15 minutes most times for the sky to dry and then I can paint over it already! So I usually block in other areas while that is drying and by the time I am done with that, the sky is dry!

Trying out WSO painting is really going to alter the way I think about the painting process. I guess I was finally getting around to the conclusion that an oil painter would have to have more than one painting going at one time if they wanted to be painting often. I tend to go in spurts, like 2-3 hours on Saturday and Sunday, usually finishing a single acrylic painting (small - 11X14) in a weekend. I will have to become more patient for the completed painting and/or do more than one at a time, maybe working on both acrylics and WSOs simultaneously.

I hadn't heard of the Cobras before reading this group - I don't think they are in the Sean Dye book that I got from the library and they certainly weren't anywhere in town here. I will have to take a look at them some time, too. Right now, I am waiting on my order for the Duo Aqua's and going to work with my new Golden OPEN Acrylics and see what happens. I am really curious as to the look of the finished product with oils compared to my acrylics and how they differ.

You don't have to give up painting you sky first when switching over to oils. I do it all the time because I like a smooth sky even if it has lots of clouds in it. I save the texture of the paint for the middle and foreground. I always feel like I'm patching up the sky when I try to make changes to it after I've started painting the mid ground over it. I may highlight the tops of the clouds more after I finish just to add more balance to the painting. It is all in what you want to accomplish. You are free to experiment with however you want as long as you keep the fat over lean concept in mind.