What kind of linseed oil in oil painting?

what is the difference in raw and boiled linseed oil, and which one is used in oil painting? Is there an oil painter out there that could answer this for me? Can I use acrylics to get the same affect, and how would I do this?What kind of linseed oil in oil painting?
First, acrylics and oils have distinctly different properties. Each has their place. There are certain effects using oil paint that simply cannot be achieved using any other medium. The open time, (the time that the paint remains wet and workable), as well as the brilliance of color enhanced by the translucent quality of oil is an integral part of its advantage over other mediums. Although there are drying retarders for acrylic these do not equal out the playing field. The open time is still significantly short. Adding too much retarder creates a paint film that is weak and may even wipe off in some cases. I encourage everyone to learn how to use oils. The medium is rich and offers a wealth of possibilities when understood.





Now, there isn't a rule suggesting you are supposed to use one form of linseed oil over all others. Linseed oil is used in a wide variety of forms for different effects. It is available raw, boiled, refined, vacuum bodied, sun-thickened, just to name a few. Stand oil is a processed form of linseed oil. Raw linseed oil dries slower than ';refined'; or ';boiled'; linseed oil.





There are advantages in blending oils to derive certain properties in paint. Paint formulators take advantage of these properties to achieve certain effects in paint, something informed artists could also do by better understanding these qualities.





The key differences are the result of two important physical properties of drying oils: the degree of polymerization and the acid value of the oil. These two properties are affected by the treatment of oil -- typically using heat -- that changes one or both of them. Heat treatment of oil makes what is called ';bodied'; oil, which is the more accurate term for what many call ';stand oil.';





Raw and refined linseed oil have good brushing properties. Paint made of essentially raw or refined linseed oil has a short, buttery, consistency that lends itself to easy brushing. The flow of such paints is poor, however, and it leaves brush marks. Raw linseed oil has an acid value of 4-7, while alkali refined linseed oil less than one. Exceptions to this are special refined oils made with high acid values to obtain better pigment wetting properties.





The outstanding property of linseed oil is its excellent durability. It is therefore used more extensively in paint than any other drying oil.





Extra High Viscosity, Vacuum-Bodied Oil





Bodied Oil





Bodied oil is polymerized oil made by heating refined linseed oil at high temperature for a certain amount of time. Where color and low acid numbers are important it is heated either in a vacuum or under a blanket of inert gas. Bodied linseed oil has an acid value in a wide range, depending upon how it is heat treated.





Blown Oil





Blown linseed oil is essentially partly oxidized oil made by passing air through at high temperatures. Since completely oxidized oil would be solid, partially oxidized oil is exceedingly viscous. The typical viscosity is Z-2 to Z-4 in the Gardner-Holt Viscometer standard. The acid number of blown linseed oil is typically high.





A small amount of blown linseed oil may be added to very short paint (called ';puffy'; paint) that typically grinds very slowly to speed up the grinding time.





Pale Drying Oil





Boiled Oil





Heating raw oil, adding driers and cooking it in an open or closed kettle is how boiled oil was made. Today, liquid driers are added to refined oil and heated briefly at lower temperatures to effect complete solution.





Color Retention





Bodied oil has better color retention than either unbodied oil. This can be understood if we consider that we have an oil that has gone partway toward a dried film via polymerization. Such a film, drying faster than a similar film of unbodied oil, absorbs less oxygen by the time it is dry. Since it is the oxidized film that is mainly responsible for yellowing and since a polymerized dry film has oxidized less than unbodied oil, we can understand why it has better color retention.





Bodied oil has better color retention than blown oil. It is also easier to understand why oil that has been partly oxidized by blowing will end up with a greater degree of oxidation when dry than one in which some of the double bonds (oxidizable bonds) have been removed by polymerization. Blown oil has poor initial color, due to the oxidation during the blowing process and poor color retention due to the further oxidation taking place while the film is drying.





Flowing and Leveling





Bodied oil has very good flowing and leveling properties, but not as great as that of blown oil. Brushing is more difficult with bodied similarly to blown oil.





Due to the viscous nature of bodied and blown oils, they have a tendency to be more difficult to brushing, because they pull or feel sticky. It is more difficult to separate large molecules in viscous oil than it is smaller molecules in thin, unbodied oil.





Gloss





Bodied oil much higher gloss than raw or unbodied oil, although similar to blown oil.





Wetting Properties





Bodied oil has good wetting and grinding properties. However, blown oil has better wetting properties. This is because the acid value is higher in bodied oil than in unbodied oil and typically even higher in blown oil.





Penetration





Due to the large molecule size, paints incorporating bodied and blown oil have much better holdout or non-penetration than similar paints based on unbodied, thinner oils. The large sized molecules have much less tendency to penetrate a porous surface.





Water Resistance





An unusual property of blown oils is their tendency in paint to tolerate large amounts of water. Blown oil is sometimes used to make water-sensitive paints less so, and to correct paint that sometimes increases viscosity due to its water sensitivity. The addition of a small amount of blown linseed oil often corrects this problem.





The increased polarity induced by the double bonds of blown oil gives it better moisture resistance properties, and better flowing and leveling properties than unbodied and some bodied oils.





http://naturalpigments.com/education/art鈥?/a>What kind of linseed oil in oil painting?
You are 'supposed' to use refined/boiled linseed oil, but I like to use raw. I think it is thicker.


I'm not sure what you mean by getting the same effect, but you can buy slow-drying acrylics, shiny acrylic medium or water-soluable oil paint (which dries faster and you don't need to use oil).