Oil Painting 101 - Mediums
Many people have asked what mediums to use in oil painting, and want to know what each one does. "Can't I just paint with the paint and not add medium?" Of course you can, and that is actually a very good idea. Just use the oil that comes in the tube as the vehicle. Spread your paint very thin, scrubbing to make it thinner in the beginning of the painting so that it is lean, and use more and more paint as you go. For glazing you should use paint that is inherently transparent and spread it thinly then wipe off until you have the look you want. Doing so will make for a sound painting structurally with the paint layers drying at a consistent rate from top to bottom. However, to facilitate certain looks, or to make paint do certain things, or to "stretch" your paint, a medium may be added to it. A medium is going to do one or more of six things. It will make the paint thinner or thicker, more glossy or more matte, and either dry faster or dry slower. Realizing that you only have to know six things makes this easier, doesn't it?! Some mediums come ready to use right out of the bottle. Some need to be mixed with other things.
Look at the following scale:
Look at the following scale:
Consider that thinners such as Turpentines and Odorless Mineral Spirits (OMS) are "lean", and Oils (linseed, stand, etc) are "fat". Adding anything at the extreme ends of this scale in excess may break down the oil paint on a molecular level. We want to use a medium that is closer to the middle portions of the scale. The Oil in the oil paint is what is known as the "binder" and the oil molecules must cross link as they dry to facilitate a strong paint layer. Adding too much, or straight OMS, will make the paint too lean and can break down the oil binders which leads to a weak structure that may feel chalky to the touch and will actually wipe off with a rag. In my early paintings I actually had this happen and I wondered what the heck was going on!
The other extreme to that scenario is adding too much oil to the paint, or making the paint too "fat". Paint that is too fat will dry to a wrinkly film. This is because as oil molecules take in oxygen to dry, they become larger. Wrinkled paint is the result of too much oil. We need to find a happy medium, if you will pardon the pun. A 50/50 mixture of oil to OMS will produce a "happy medium" that will produce a slow drying liquid. It will work adequately to change the viscosity (thinness or thickness) of the paint to obtain certain effects. (Note: High Viscosity paint is thick; Low viscosity paint is thin) What? You don't want the paint to dry slower? Me neither, most of the time. Many, if not all Alkyd mediums are a good medium to use as they are relatively in the middle of the scale. Alkyd mediums are made of an alcohol/acid based resin (hence the name Alk-yd, pronounced Al'-Kid) and increase the drying rate as well as the glossiness of oil paint. Many Alkyd based mediums can be used straight out of the bottle, and come in various viscosities. The two main lines of Alkyd mediums, and the two that we carry, are Winsor-Newton's Liquin line, and the Gamblin Oil Galkyd line. Both work quite similarly. They both come in fluid versions, medium viscosity versions, gels and pastes. To thin the mediums further, as well as increase the drying rate but decrease the glossiness, one could add OMS to the medium at no more than 50/50 ratio. That will keep the medium above the 25% line on the lean side. To thicken the medium as well as slow the drying rate and increase the glossiness further one could add Stand Oil. Or, to thin the medium and slow the drying rate one could add Linseed or Poppyseed oil. Poppyseed oil is a more clear oil that may have a less yellowing affect on the paint.
Another medium, sold by Gamblin, is called Neo Megilp. It is a soft gel with a silky texture, still in the middle of the "fat" scale, that increases the glossiness, slows the drying rate somewhat, and helps create luminous glazes. It is a medium that replaces the old Meroger (Me-ro'-jay) medium of yesteryear. Meroger, also called Megilp, was used extensively until it was realized that it caused darkening and yellowing of the paint over time. Artists used it anyway because it was such a fantastic medium. It was made from boiling Lead in a mixture of Oil and Mastic Varnish. Neo Megilp is the modern, safe, non yellowing version of this classic medium and is by far my favorite for middle/latter stages in a painting.
Another medium, although little used, is to mix beeswax and OMS. Gamblin makes a premixed version called "Cold Wax Medium". It is used to thicken the paint and create a matte finish. I have personally never used it because I desire neither of those qualities in my paintings, but it is something to consider if YOU do. Cold wax may be added to any premixed or Alkyd medium
to thicken it and decrease glossiness. It is an inflexible medium though, and if mixed more than 30% by volume to the paint then it should only be used on a rigid substrate such as wood or hardboard panel, and not on a flexible canvas.
Ok, now we know basically what the mediums do. So now what? Well, first we need to know "how" we like to paint to decide if we need a medium. I personally like to paint in thin glazes, building layer upon layer, to achieve a luminous look. Some of you may paint very thick or impasto. Some of you may not even know! I will give a little guideline that should help keep the "fat over lean" quality of your painting.
Now, as stated in the beginning, you can paint just fine by using no medium at all. I generally use that technique for painting on location (Plein Aire), or when doing small studies Alla Prima ("all at once"). But, when doing a "major" painting I generally follow a similar process for each one. I begin with a lean mixture of medium by mixing 50/50 Galkyd or Liquin original (or lite) with OMS. This will create a quick drying layer that can be built upon quickly, yet keeps the integrity of the oil binders intact. After the initial blocking-in wash is complete and dry I will use Galkyd or Liquin pretty much straight from the bottle.
Here is where you may want to use a different medium depending on your needs. A perfectly good medium is to use 50/50 OMS/Stand Oil (high viscosity) or 50/50 OMS/Linseed or Poppy Oil (Low viscosity). Each will facilitate better flow rate of the paint, slower drying time, and gloss. In fact, that medium may be used throughout the painting, start to finish. Some people like to be able to work wet into wet for days on end. This medium is for you!
For the later stages, or for luminous glazes, I will switch to Neo Megilp medium. I will create glazes in one of two ways. I will either mix the Megilp right into the paint and brush it on, or I will use the more traditional method and actually paint the clear medium right onto the canvas, then brush on the paint into the jelly like film. Then, using a clean brush or rag I will remove some of the paint until the glaze is how I want it to look. Turner used that technique quite effectively back in the day. You can too!
For structural integrity sake, I don't recommend using a quick drying medium over a slow drying medium. Here's why. As the paint film dries it shrinks. If the upper paint film dries faster than the lower layer, then the dry and already shrunk upper layer will have nowhere to go as the lower layer dries and shrinks. Thus the upper layer may crack.
Remember, lean paint dries quickly, fat paint dries slowly. Adhere to the fat over lean principle in oil painting and your paintings will last for ages, if not eons.
Using no medium at all is coming into great favor recently in various forums. Experts agree that the less medium you use the more likely the painting will be more structurally sound and will last generations, even hundreds of years.
So to recap: Mediums do one (or more) of six things. Thin or Thicken, Gloss or Matte, Slow or Fast. Depending on your painting style or particular needs for a specific painting you should be able to steer yourself toward the proper medium for the job if you wish to use them.
The other extreme to that scenario is adding too much oil to the paint, or making the paint too "fat". Paint that is too fat will dry to a wrinkly film. This is because as oil molecules take in oxygen to dry, they become larger. Wrinkled paint is the result of too much oil. We need to find a happy medium, if you will pardon the pun. A 50/50 mixture of oil to OMS will produce a "happy medium" that will produce a slow drying liquid. It will work adequately to change the viscosity (thinness or thickness) of the paint to obtain certain effects. (Note: High Viscosity paint is thick; Low viscosity paint is thin) What? You don't want the paint to dry slower? Me neither, most of the time. Many, if not all Alkyd mediums are a good medium to use as they are relatively in the middle of the scale. Alkyd mediums are made of an alcohol/acid based resin (hence the name Alk-yd, pronounced Al'-Kid) and increase the drying rate as well as the glossiness of oil paint. Many Alkyd based mediums can be used straight out of the bottle, and come in various viscosities. The two main lines of Alkyd mediums, and the two that we carry, are Winsor-Newton's Liquin line, and the Gamblin Oil Galkyd line. Both work quite similarly. They both come in fluid versions, medium viscosity versions, gels and pastes. To thin the mediums further, as well as increase the drying rate but decrease the glossiness, one could add OMS to the medium at no more than 50/50 ratio. That will keep the medium above the 25% line on the lean side. To thicken the medium as well as slow the drying rate and increase the glossiness further one could add Stand Oil. Or, to thin the medium and slow the drying rate one could add Linseed or Poppyseed oil. Poppyseed oil is a more clear oil that may have a less yellowing affect on the paint.
Another medium, sold by Gamblin, is called Neo Megilp. It is a soft gel with a silky texture, still in the middle of the "fat" scale, that increases the glossiness, slows the drying rate somewhat, and helps create luminous glazes. It is a medium that replaces the old Meroger (Me-ro'-jay) medium of yesteryear. Meroger, also called Megilp, was used extensively until it was realized that it caused darkening and yellowing of the paint over time. Artists used it anyway because it was such a fantastic medium. It was made from boiling Lead in a mixture of Oil and Mastic Varnish. Neo Megilp is the modern, safe, non yellowing version of this classic medium and is by far my favorite for middle/latter stages in a painting.
Another medium, although little used, is to mix beeswax and OMS. Gamblin makes a premixed version called "Cold Wax Medium". It is used to thicken the paint and create a matte finish. I have personally never used it because I desire neither of those qualities in my paintings, but it is something to consider if YOU do. Cold wax may be added to any premixed or Alkyd medium
to thicken it and decrease glossiness. It is an inflexible medium though, and if mixed more than 30% by volume to the paint then it should only be used on a rigid substrate such as wood or hardboard panel, and not on a flexible canvas.
Ok, now we know basically what the mediums do. So now what? Well, first we need to know "how" we like to paint to decide if we need a medium. I personally like to paint in thin glazes, building layer upon layer, to achieve a luminous look. Some of you may paint very thick or impasto. Some of you may not even know! I will give a little guideline that should help keep the "fat over lean" quality of your painting.
Now, as stated in the beginning, you can paint just fine by using no medium at all. I generally use that technique for painting on location (Plein Aire), or when doing small studies Alla Prima ("all at once"). But, when doing a "major" painting I generally follow a similar process for each one. I begin with a lean mixture of medium by mixing 50/50 Galkyd or Liquin original (or lite) with OMS. This will create a quick drying layer that can be built upon quickly, yet keeps the integrity of the oil binders intact. After the initial blocking-in wash is complete and dry I will use Galkyd or Liquin pretty much straight from the bottle.
Here is where you may want to use a different medium depending on your needs. A perfectly good medium is to use 50/50 OMS/Stand Oil (high viscosity) or 50/50 OMS/Linseed or Poppy Oil (Low viscosity). Each will facilitate better flow rate of the paint, slower drying time, and gloss. In fact, that medium may be used throughout the painting, start to finish. Some people like to be able to work wet into wet for days on end. This medium is for you!
For the later stages, or for luminous glazes, I will switch to Neo Megilp medium. I will create glazes in one of two ways. I will either mix the Megilp right into the paint and brush it on, or I will use the more traditional method and actually paint the clear medium right onto the canvas, then brush on the paint into the jelly like film. Then, using a clean brush or rag I will remove some of the paint until the glaze is how I want it to look. Turner used that technique quite effectively back in the day. You can too!
For structural integrity sake, I don't recommend using a quick drying medium over a slow drying medium. Here's why. As the paint film dries it shrinks. If the upper paint film dries faster than the lower layer, then the dry and already shrunk upper layer will have nowhere to go as the lower layer dries and shrinks. Thus the upper layer may crack.
Remember, lean paint dries quickly, fat paint dries slowly. Adhere to the fat over lean principle in oil painting and your paintings will last for ages, if not eons.
Using no medium at all is coming into great favor recently in various forums. Experts agree that the less medium you use the more likely the painting will be more structurally sound and will last generations, even hundreds of years.
So to recap: Mediums do one (or more) of six things. Thin or Thicken, Gloss or Matte, Slow or Fast. Depending on your painting style or particular needs for a specific painting you should be able to steer yourself toward the proper medium for the job if you wish to use them.