History And Use Of Mediums

Materials History ,

Through the Renaissance, artists worked with combinations of tree resins, thickened vegetable oils, waxes and balsams. The exact organization of these raw materials is open to speculation and may differ from one artist to another, and even within the practice of an individual artist.

However, the basic desire to create an oil paint film with a degree of gloss and depth seems to be a constant.

When oil colour is simply diluted with turpentine, it loses some of its body and also appears to become slightly matt upon drying.

If a small addition of paint medium is incorporated into the paint layer, and then it is diluted, the paint film retains more of its original gloss and lustre. This simple step helps avoid a reliance upon varnishing: in essence, the varnish constituent is then built into the paint film itself.

The antique formulations of these kinds of painting mediums often involved the presence of sun-thickened linseed oil, well-known for its self-levelling properties, excellent gloss and drying capabilities. This viscous oil would invariably be blended with natural tree resins, such as Mastic, from the Greek island of Chios. This combination may also have been treated with lead-based siccative to speed up drying times. To this formulation, an addition of tree balsam may also have been included, to impart yet more gloss to the paint medium.
Contemporary thought about the use of paint mediums errs somewhat on the side of caution.

Rather than using toxic and unpredictable lead drying agents, we have prepared a selection of oil-resin-balsam-wax blends, which avoid any driers (with the exception of Dammar Glaze Medium). In place of sun-thickened linseed oil, we use best grade viscous linseed stand oil (a partially polymerised linseed oil, which is fat in consistency but which self levels perfectly and imparts elasticity into oil paint films and does not yellow/darken appreciably over time).

Otherwise, the raw materials used here are consistent with those of the past. As an alternative to mastic resin (in use for over 800 years) we make use of best quality Indonesian dammar resin (used in paint mediums since late 18C) dissolved into the best grade double rectified turpentine. In our opinion, this is the best and only solvent for use in oil paint technique: it evaporates slowly and evenly and has a delicate flowery odour.

Larch turpentine from the Austrian Tyrol is the best grade tree balsam for use in paint mediums: the balsam is collected by drilling into the core of the tree, to obtain a form of resin-sap which is highly resistant to darkening when incorporated into paint films.

Our unique Oleo Resin Glaze Medium makes use of very pale, highly elastic Canada balsam. This high grade oleo-resin imparts excellent depth and lustre to oil paint films and possesses exceptional clarity.

To create matt or satin-matt paint films, high grade pure bleached beeswax can be fused with tree resins and oils. This makes paint mediums which allow the possibility of mild impasto within the paint film. Although beeswax is the most flexible of all natural waxes, it works best on flexible (i.e. canvas) supports, when fused with oil or resin-oil combinations.

The paint mediums are prepared without drying agents, to compliment the working properties of our oil colours, which are also prepared without use of drying agents. By adding only 10-20% paint medium to oil colour, one can tweak the sheen of the paint film and help avoid loss of gloss within the paint film.

In this kind of ratio the normal drying rate of individual colours is preserved.

If quicker-drying is required, we have prepared one medium (Dammar Glaze Medium) which can be introduced to speed the curing rate of the paint film, again when added in the ratio of 10-20% to oil colour. One can also mix this medium 50:50 with all the other mediums to help speed drying times. Remember that over-use of drying agents could cause problems over time in the dried paint film.

Final varnishes are best applied to thoroughly dried oil paint films. For example, a thinly painted picture may take 6-12 months to “cure” enough to be varnished. Remember that any varnish application will close the paint film, thereby stopping the paint layers from drying if not already dried out. Our Mastic Varnish is clearer than Dammar Varnish and it can also be thinned with turpentine to create a super-fine varnish layer. Varnish is best applied in dry conditions (avoid damp/humid atmospheres, which may cause “blooming” or clouding in the varnish film upon drying).

Sometimes oils and varnishes might separate on standing in the container, which can be simply shaken to remedy this. It is also worth remembering that turpentine when exposed to direct sunlight in glass containers can spoil and must be discarded; this is apparent when the turpentine goes very cloudy. Although we do sell turpentine based products in glass they are generally for immediate use. Try and store these products in darkness.

27 Responses to “History And Use Of Mediums”

May 24, 2016 at 1:28 pm, Whitney Kurlan said:

Dear Michael.
I’m curious if there are reciepies for mediums and oil additives for acrylics? I realize you’re an expert in the oil paint field. I am currently coming back to my art after a 15yr break…. due to a career ending spinal accident. I chose to work with acrylics for several reasons. Health, quickness of drying time and cost. I have used oil paints in the past but I felt there was so much more to study in the field of oils that I currently didn’t have the knowledge right now nor did I frankly have the quality of skill I felt deserved oil paint at this time. I’m currently using Atlier Interactive acrylics which are the closest crossover to an oil paint with the ability to rewet a dry paint after 2 weeks… So it begs me to ask with your knowledge of reciepies do you think any of your mediums or oils could be applied to this brand of acrylics?
I would love to switch over specifically to your paints but until I reach a level of skill I feel is compatible with the time and effort you’ve put into creating your mediums and I can find a source of income to support buying your paints..I’ll have to wait. My art is more my only opportunity to earn a living so I’ve been studying hard watching as many free tutorials and have graciously been given by Richard Schmidt a set of his DVDs by him to help me in my quest to teach a higher level of skill.
Thank you so much. Your dedication to your craft is unmistakably remarkable.
Whitney Kurlan.


May 25, 2016 at 1:13 pm, Austin Schneider said:

Dear Whitney,

Thank you for your email, to be completely honest I am afraid I think it best not to consider mixing any oil paint or mediums with wet acrylics if this is what you are asking. If you are painting oil paint upon acrylics that is okay, the other way around is generally frowned upon. I must admit I am impressed that you can keep oil paint open for as long as 2 weeks. Having said that I would also suggest that you could consider just using our oil paints as many would also be dry within these timescales.

I am delighted also you have found your way back to art after such a challenge to health!

Best Wishes



January 08, 2017 at 9:33 am, Rocco Amico said:

I have now been painting for a while using the Dutch old masters style, but I have been trained with a mixed modern technique, this being; a drawing on canvas fixed with an acrylic earth colour then a mid tone imprimatura also in acrylics is applied all over, leaving the drawing visible, then still with acrylics I produce a monochrome under painting. Then I cover the whole area with liquin and start to apply the oils paint glazing layers. With the liquin drying overnight I can then carry on painting the glazes on top of this without waiting for long drying times. I have been very successful with this method particularly because the acrylic underpainting drying so quickly and also the liquin doing the same for the oils layers, it allows me to work at a speed, however I would like to ditch the acrylics and carry out the underpainting in oil, and stop using the liquin in the oil glazes, in favour of a more natural product such as your historical mediums. could you please advise me if any of your Historical mediums can achieve the overnight drying time of the liquin?
Kind regards,


January 18, 2018 at 6:02 pm, Michael said:

Dear Rocco,

Thank you for your email. If you have a tecnnique that you feel works for you and gets the result you like stick with it, however moving from one medium to another, acrylic to resin based is likely to be problamatic, also I think if you research liquin you will find it cause a lot of people concern.

I would advise a more traditional and therefore proven route.

Best Wishes



March 25, 2017 at 3:45 am, Tony Cuzzilla said:

Dear Michael,
I have spent quite some time on what started out as an attempt to make some notes on oil painting materials from some authoritative sources, only to find myself baffled by inconsistencies and contradictions on (for example) just what x or y form of linseed oil actually is and which is better and why, not to mention inconsistencies between what handbooks say you should do or not do and what recent analyses show that the greatest painters from van Eyck to Rembrandt actually did in terms of grounds and mediums. But I would like to ask about one particular issue.
We are told to be aware of the oil content of different colours, and to paint fat over lean, and that lead white for example is the leanest of all at around 15% oil – by weight (as oil content is usually expressed). But then an online source that seems to deserve respect tells me that what matters is the oil content BY VOLUME, and that by volume a given amount of flake white has as much oil as say ultramarine blue (about 50%). No other source I have seen mentions this, and the source in question doesn’t tell me what to do with this information.
Also, a well known brand’s PDF I downloaded a few years back says that, regarding the fat over lean rule, “contrary to many publications, neither oil absorption, nor oil index information is required for observing this rule.” The same brand’s current online information on fat over lean omits this sentence but is otherwise the same as the PDF.
What does it all mean?


January 18, 2018 at 6:02 pm, Michael said:

Dear Artist,

Indeed all confusing and sometimes down right incorrect, writers will often try and dress their sites up so as to appear more learned. I suggest a back to basics approach, the section in the ‘Ralph Meyer book Methods and Techniques’ covers the matter accurately re oil content and fat over lean, however there is a mistake regarding guidance on damar varnish, so I urge caution.



January 27, 2018 at 3:43 pm, Barbara Snyder said:

Dear Michael,
I found David’s question to be very interesting and am wondering if you could elaborate further; specifically in relation to the M. Harding line of oil paints (which I am heavily invested in).
Since you list Oil Content in your paints as High, Average and Low and Drying Times as Slow, Average & Fast I assume this information must be important to the artist when observing the fat over lean rule.
So for example, if one is using either Lemon Yellow, or Lead Tin Yellow Light, or one of the Cadmiums (which are all Fast Drying and have Low oil content), to create beautiful foundation colours in either a landscape or still life, perhaps, then is it OK or is it CONTRAINDICATED to use Alizarin Crimson or Alizarin Claret over that layer when creating shadows and dimension?
A definitive answer would be much appreciated.
Thanks, B

I love using your paints, the colours are fantastic and consistency is perfect for my way of painting.


February 21, 2018 at 11:14 am, Michael said:

Dear B

Great question, indeed we list the info for those reasons however experienced artists will just know which colours are lean and fat from previous years of handling, just picking tubes up and feeling the different weights is a much easier way of telling, lean being heavy obviously.

If I am understanding your list of colours correctly you have lower layers which are lean eg lead tin yellow, with aliz crimson over the top. This is fine and the correct way around. It is only when this rule is completely disregarded that problems can occur. For example a sky paint with a thick layer of prussian blue then clouds applied as a later layer of lead white. Thin layers tend to be more forgiving when the rule is broken.

Hope this helps?

Thank you also for the trust you place in me.



April 01, 2017 at 8:53 am, daniele said:

Hello michael Why you don’t use mastic varnish in your medium?
it is more brittle than dammar?


January 18, 2018 at 6:02 pm, Michael said:

It has a reputation of yellowing and is also very expensive. While there are better options we do not have it in our range.


August 04, 2017 at 3:20 am, Mary Naylor said:

Do oil paints go bad?


December 07, 2017 at 1:14 pm, Joelle Harding said:

I still have paint which I made in the 1980’s and it is perfectly useable, if made well they shouldn’t go bad!



October 10, 2017 at 9:01 pm, David Foster said:

Hi, Michael,
I’m studying the Venetian technique of oil painting and ran across this short curious YouTube that caused me to think he may be using one of your mastic mediums, but I can’t be certain due to his Scots accent which either sounds like “mastic, muslin or mustin.” Are you familiar with this process and is this one of your products? BTW: your paints are terrific!


January 18, 2018 at 6:03 pm, Michael said:

Dear David,

Thank you for your email, I am afraid I cannot hear either as the sound quality is poor, I suggest you contact him and ask directly.

Best Wishes



October 26, 2018 at 3:26 pm, James Bannon said:

> The word you are looking for is “misting”: basically, painting a thin, semi-translucent, layer of white over the painting. (I’m no artist, so I’m not sure what it would achieve, but apparently it was used by some of the Dutch masters.)


August 08, 2019 at 12:41 am, Christiane said:

Dear Michael Harding,

I would like to try using some of your mediums. I have been using a mixture of about 1/2 Gamsol Mineral Spirits to 1/2 Galkyd Medium with about 2 Tablespoons Cold Wax Medium for a number of years. I have become unhappy lately with speeded drying time due to the Galkyd and I think its tendency to make my oil paints very tacky when applying wet on wet on warmer days.

I do like the way a little wax gives a more satin finish however I am not looking for impasto. And I do not want a high gloss finish. I guess something in between. I was wondering if I could mix some of your Resin Oil Wax Medium with one of your other mediums such as the Oil Paint Medium if I wanted to tone down gloss? Or if you have any suggestions? Also do your mediums have give off any odors that might cause headaches if one is sensitive?

I started using your oils a few years ago and they are by far my favorite oils now and such a joy to paint with! As a paint nerd I think I also have just as much fun reading about the properties and history of each color and figuring out which will suit a particular part of my painting best. I really appreciate your dedication to providing your customers with such information. Few companies do and at least for me and my process I find it extremely helpful and fascinating. Your paints actually appear in the titles of my current work where I have been employing a technique used by Whistler, using specific colors to describe the painting as an “Arrangement.” For example, “Jenny: Arrangement in Opaline Grey and Titanium White 2.”

Thank you again for your dedication to creating and educating artists about the practice of oil painting. And thank you in advance for any suggestions about using your mediums.

A devoted customer,


August 15, 2019 at 9:48 am, Michael said:

Dear Christiane,

Thank you for writing to me.

After reading your message I wonder if perhaps they have changed something it might be worth contacting them also to discuss.

In regards to toning the gloss down – Yes you could, obviously this is a very subjective

Headaches – Yes they do and you should always paint with any medium in a well-ventilated studio, even the so-called odourless have spirits and just because you cannot smell it doesn’t mean it’s not there!

Thank you for your very kind comments I am glad they work for you please tell your artists friends.

Best wishes,



September 27, 2019 at 10:20 pm, Christiane Lyons said:

Thank you for your reply! It was very helpful. Just read it today because I was researching your linseed oil!

I’m finding I like using linseed oil as a medium better than galkyd. I’ve noticed you mention alkyd based mediums as comprising quality in your responses to Artist and Illustrator magazine. Could you elaborate? Is this why paint appears more vibrant with linseed based mediums?

Can one just use linseed oil as a medium? I’m not one to be too exact about as to how much oil to medium I’m using, but mix as I work wet on wet. Is there a danger in using too much linseed oil to thin out an oil? Would you advice combining with a turpentine like in your PM1?
I did just purchase your PM3 and PM6 to experiment with!

I definitely recommend your paints to all my painting friends! Actually recently, recommended your oils to the LA artist Meg Cranston who actually teaches an oil making class at Otis College of Art and Design.

Thank you in advance for time and advice,


December 04, 2019 at 1:06 pm, Michael said:

Hi Christiane,

I have answered in line, in bold for your ease of reading:

I’m finding I like using linseed oil as a medium better than galkyd. I’ve noticed you mention alkyd based mediums as comprising quality in your responses to Artist and Illustrator magazine. Could you elaborate? Is this why paint appears more vibrant with linseed based mediums? Its one of those things ‘it just is’.

Can one just use linseed oil as a medium? I’m not one to be too exact about as to how much oil to medium I’m using, but mix as I work wet on wet. Is there a danger in using too much linseed oil to thin out an oil? Would you advice combining with a turpentine like in your PM1? You have to remember the more oil you add the more chance of yellowing and possibly wrinkleing if the paint is goopy and thick.

I did just purchase your PM3 and PM6 to experiment with! Always remember the less medium you add the more likely you are to have stability.

I definitely recommend your paints to all my painting friends! Actually recently, recommended your oils to the LA artist Meg Cranston who actually teaches an oil making class at Otis College of Art and Design. Thank you that’s very kind of you.

Thank you for your comment!


October 14, 2019 at 1:26 pm, Sally said:

I’m interested in your Beeswax paste. Does this have the same properties and results as Cold Wax Medium I have seen by other brands?( Gamblin, Dorlands and Zest It.)


December 06, 2019 at 4:04 pm, Michael said:

I have not used any other brand other than my own so I could not say, I would recommend trying it and comparing them 🙂


December 04, 2019 at 7:39 pm, Ruby Lewis said:

Dear Michael,

I’m currently studying for my Masters Degree and having used traditional methods of rabbit skin gesso on wood panel with oil paint, I would like to look at building thin layers of oil colour using Damar varnish (homemade) as a medium. Ideally this would be of a pouring consistency as I will have an initial drawing that I would like to show through some parts of the paint itself.How is it best to achieve this and also can I build layers of different colour using the Damar medium? If possible I would also like to achieve a combination of both matt and gloss effects…not sure if I am asking too much of the paint itself or if it is at all possible?

Thank you so much for your time,



December 09, 2019 at 2:06 pm, Michael said:

Hi Ruby,

Thanks for your message.

Yes, it is possible – Just keep it thin in layers.

Good luck with your masters!

Have a great week,



April 25, 2020 at 11:27 am, Hans Jakobsen said:

Dear Michael Harding and colleagues,

Your marvelous colors really are a revelation. It feels like to me like they are “pre-lit”, right out of the tube. I have 2 questions in relation to this statement: “By adding only 10-20% paint medium to oil colour … In this kind of ratio the normal drying rate of individual colours is preserved”

1) Is it safe to assume, that if PM6 is used in such moderation, it will not offset the “oil index” as the primary factor in constructing a solid painting based on “fat over lean logic” ?

2) Should PM6 be regarded as a “fat medium”, or rather “neutral”, due to a balance, as it were, between stand oil, Dammar and Venice Turpentine ?


June 11, 2020 at 12:14 pm, Michael said:

Hi Hans,

PM 6 will increase the fat content and so consideration for this should be made when building layers.

Best wishes


December 11, 2021 at 6:56 pm, Andy Newb rey said:

Dear Michael,

I’m wanting to create a more fluid, yet consistent feel. Knowing my absentmindedness, I would like to remove the thinking about adding medium during the painting process. I also do not want to lose gloss.

What is your opinion/thought on premixing your PM1 Oil Paint Medium with oil paints? Say, mixing entire tubes with 5-10% with PM1?


January 10, 2022 at 5:25 pm, Michael said:

Hi Andy,

Should be fine but keep the layers thin and be aware of the ‘fat over lean principle’


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