Busting the Myths of Oil Painting: Fat over Lean

Scared of Oils

A recent article in a main UK art magazine made me remember why I took so long to discover the joys and beauty of using oil paint. Although oil paint is one of the oldest and widely used art materials, many people will hesitate to use it, like me at the time, because of all the stories they hear about toxicity, strict rules, and the complex array of materials needed. For a long time I feared all these technical issues would spoil the joy of painting for me, and so stayed away from oils.

However over the past ten years I have learned a lot from professional and amateur artists who were a goldmine of help and information. They provided experience and – sometimes opposing – opinions on the use of oil paints, mediums, techniques and materials and when I decided to jump into oils I could experience a lot of it myself and come to my own conclusions. Books, many online resources, chats with other artists and practice have got me where I am today. I have not read enough books nor learned enough yet to be able to publish the one-and-only guide to using oil paints (far from it, in fact) and I cannot test the longevity of my painting techniques ( where is that time machine when you need it), but I hope that my take on things might help some hesitant beginners to get started. I do my best to always paint with archival materials and according to techniques that will stand the test of time as best as I can. I strongly believe that whomever is gracious enough to pay money for my work, should expect it to be created with proper, professional materials that won’t disintegrate over time. But I am also painting because I love doing it and I avoid methods and materials that are overly methodical or complex.

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The enormous amount of questions I had and many beginners have about oil paint is enough to put anyone off the stuff forever. Which brands should I choose, which colours do I start with, can I mix different brands, what is a medium and do I need it, and which medium should I choose? Do I need turps or white spirit and what is the difference, can I use solvents from the hardware store, how can I avoid toxic fumes, are the paints toxic Picturethemselves and are they safe to use with pets/kids around (or any living creature like artists perhaps)? How do I mix my colours, do I premix or not, should I use a brush or a palette knife to mix? Is it ok to use ‘convenience mixes’ such as skin/sky colour? What does fat over lean mean and how do I apply that rule? Can I clean my brushes in solvent, or in oil or with washing-up liquid? What is glazing, scumbling, impasto and alla prima? What support should I use and which is better in the long run: cotton or linen, wood, or aluminium? Should I prime canvas myself, and if so how, or is it ok to buy ready-primed materials? What is the best primer to choose and how do I apply it?

And I haven’t even started on brushes or pigments yet…..Surely this would put anyone off who just wants to have a go and have some fun?

 

Keeping it Simple

All this said, there are always those who enjoy a methodical and exact approach to what they do. They might enjoy finding the answers to all these questions and carefully learn and note down medium recipes and priming methods. I must admit I am not one of them, and although I want my work to be sound and archival (and therefore I do learn about pigments and priming for example) you won’t find me measuring out exact oil/solvent ratios for my medium with a pipet (I was always rubbish at maths and science at school). It was a revelation to find out that with oil paints there is actually the option of KEEPING IT SIMPLE.Of course a blog post like this is not the place to answer all of the questions above and I am not going to try to unless you really want me to. Time and place and all of that. But when I learned that it really doesn’t have to be as complicated as I feared and that you can actually just buy a canvas, a brush and some paint and just go for it, a whole new world opened for me. When I hear some others talk about the strict rules and regulations of using oil paints it sounds more like a chemistry project instead of art.

​The Fat-over-Lean principle is one of these (in-)famous ones that has a tendency to scare people. Talk of cracked paint falling off your canvas in the future is scary to say the least. Not that we all envisage our art to need to last for centuries, but surely it would be nice to know that in a few decades our doodles in oils are still remotely visible.  So artists explaining this rule as if it is a vital necessity to carefully and exactly measure the oil/solvent ratio in your medium, and slowly adjust it in parts with a pipet, as you paint in clearly defined layers, are taking it too far in my opinion.

The Fat-over-Lean principle is fairly simple. Artists should keep in mind that oil slows the drying time of paint. It makes total sense that applying a quick drying paint over a slow drying paint will cause problems. The top layer of paint would dry quicker and ‘seal in’  the slow drying flexible layer underneath, causing it to dry even slower as no air can reach it, and cracking the upper layer of dried paint. Therefore, IF you decide to use additions to your paint such as solvents (making your paint ‘leaner’) or mediums (making your paint ‘fatter’ as it usually contains oil) you need to keep in mind to use ‘lean’ paint (less oil content and therefore faster drying ) first and make sure you don’t seal in oily layers of paint (‘fat’ paint and slower drying). This is especially relevant if you work with thick paint, or in layers.

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Use Common Sense

It is important to apply common sense when using additions to your paint such as solvents or mediums. Too much of it (additives I mean, not common sense) will break down your paint and pigments and cause trouble. Too much added oil will disperse the pigment and you’ll end up painting with just oil – which will dry slowly, wrinkly and has no ’tooth’ for next layers to adhere to. Too much solvent will break down the paint as the pigment will not mix with solvents alone. As a general rule it is wise to not add more than 20% or so (or so!) of medium to your paint. Keeping in mind the fat (oily) over lean (less oily) principle you should not start a painting with medium-rich paint. Many artists use only (a tiny bit of) solvent for the initial underpainting as it dries quickly and is, by definition, lean. Alternatively you can use no additions at all in the first stages.That brings me to another point.

IT IS OK TO NOT USE ANY MEDIUM AT ALL. Yes really.

Some oil painters enjoy talking amongst each other about mediums and the various recipes they discovered featuring exotic sounding ingredients. So let them. It does not mean you have to use a medium. It sounds all snazzy and exciting but honestly you can actually paint with a brush and a couple of tubes of paint. Unless you want the paint to do something that it doesn’t naturally, there is no need for a medium or a solvent. No need whatsoever. And if you find your paint too fluid or too thick, instead of adding a medium, you can also try to change brands as all brands have different characteristics. Try and experiment until you find what you like.

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Learn from Others

I am still experimenting and learning. There is a lot I don’t know and more seasoned artists do. Thankfully I can ask, read and learn and I would always recommend that artists do that. Don’t take my word, but ask others, read up and decide for yourself (that’s me covering my back). The more I learned and listened the more I realised that many artists have their own way of doing things. What works for them, might not work for you. When they say you should do this, someone else might say the opposite. Use common sense and you will find your own way. Some things are more set in stone than others, of course, such as oily paint drying slower than lean paint, and the various behavioural characteristics of types of oils, solvents, supports and pigments. But while paddling around the facts, use your own instinct and sense in finding your way. And don’t forget that the more stuff you add to your paint, the more complex the potential problems can be. Keeping it simple has its benefits.In the end I have come back to using a fluid paint brand (as I like to paint thinly) so that I don’t need to add a lot of medium. Fluids paints are Vasari, Blockx, Mussini, but I also use Michael Harding and Winsor & Newton. You are by no means limited to a single brand.

When I want my paint to be even more fluid I do add a little bit of medium, but after experimenting with quite a few (some of which had ingredients I turned out to be – ugh that was fun -allergic to) I often come back to the simplest version: a tiny drop of linseed oil. Sometimes I use a mix of linseed oil/stand oil/odourless white spirit (I have always used and liked W&N Sansodor) for detail work. I do an underpainting with a touch of of Sansodor. But most of the time and the vast majority of my paintings are painted without any additions at all. Its just paint and a brush and that’s all.

You Choose your Painting Process

So although you might not want to work like this, I just wanted to share that it does not have to be complicated. You can choose the level of complexity you apply to your painting process. Many artists will just dip their brush in a bit of medium now and then. Our aim is not to come up with the most scientifically archival painting, but with an amazing art work that will stand the test of time. So increasing the oil ratio in your medium mathematically, according to the layers of your painting, is not something we have to do in order to produce a sound and archival painting. If, like me, you don’t want to work with pipets but just brushes, just keep your sensible hat on, don’t forget some basic principles and dive in. Turning the painting process in an overly methodical science process kills the fun and creativity for me (but perhaps not you), is unnecessary, and will put off many newbies wanting to try.A brush, a few tubes of paint and a canvas is really all you need and maybe all you’ll ever end up with.

If you are a newbie dreaming of using oils, I hope these thoughts have helped to get started. I’d encourage you find more information online, in books and magazines and ask other artists if you can. If you are a more seasoned artist, I’d love to hear your thoughts. If you are a mathematician who likes pipets…well, er… never mind. 😉

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45 thoughts on “Busting the Myths of Oil Painting: Fat over Lean

  1. Great blogpost that will ease the minds of many I am sure. I opt for no, or very little, medium after experimenting with recipes from different articles and artists suggestions. I use a little linseed oil. I am always experimenting though and love reading about others processes.

    1. Hi Maria, thank you for your nice comment. You sound like me; using very little medium if at all. Glad you enjoyed my post!

    2. I always run into problems when trying something new. It’s part of the learning process. I had problems with heat and cold so the paint reacted different every time. That makes for longer progress time but I know now how to work in different extremes. I love you’re simple method using common sense. I work with several artists and none of us use the same techniques. It is all about figuring it out for yourself. Doing it is how you learn. We have lots of advice and info at our fingertips but much of it all though invaluable will never be used because it doesn’t apply to how I work. This takes time to realize after much experimenting. But all we do is worth the effort. Stay positive. Thanks for the straight forward explanations.

  2. Excellent, Sophie – very clear, sensible advice. Mediums can be helpful to achieve particular effects and particular paint-handling, but you can get a very long way with just paint, a little bit of linseed, and a little bit of white spirit – fancier mediums should only come into play at a point where artists have a *very* clear idea about what they are trying to achieve with them. A lot of people with a few month painting under their belt take a big detour into mediums in the hope that this will make them better painters, when they would usually benefit far more from improving their drawing skills and colour-mixing. (And I say this as someone who sells some mediums!)

    1. Thank you Dave. You know your stuff (your mediums I should say) so I really appreciate your comments. Well said. 🙂

  3. Really enjoyed your blog. Filled with common sense as far as I see. Also sharing it on my timeline to reach more artists (whether they agree or disagree). Found this refreshing and down to earth. Thank you!

  4. Have you had any feedback on water-soluble oils? I have been using Holbein’s Duo-Aqua for a while, and as I understand it, they are still oil paints in the traditional sense and can be mixed with regular oils. They seem the same to me, but I am a lifelong watercolorist. The advantage is in the clean-up, which is fine with water only unless they are mixed with traditional oils. Holbein makes a medium similar to Liquin if you use a medium,as well as water-soluble stand oil, etc. and they are absolutely odorless. I see no difference in the consistency other than what one might expect between pigments. The oldest painting I have with these materials is only 10 years, but seems fine and I can’t see the difference. If I need a color that I can’t find I simply use another brand of traditional oils. And I never use water as a medium. Has anyone any experience with these paints, since there is so little written in the blogs that I can find. I’m not a beginner and my initial attraction was the odorless aspect and no need for solvents. My studio is part of my house and I personally love the smell of oil paints but others do not!

  5. Wow. That was a bit releasing! Sometimes I think the less we know the better off we are. I have done a couple of oil paintings recently after painting in acrylics for years and my naivety helped me create two lovely paintings. Then I started thinking about the mediums etc and now am totally scared to the point of not painting almost! I painted a layer using a lean medium. My question. If my lean medium layer is completely dry, can I paint another lean layer over it? My No.2 medium seems to be really sticky and drys on my palette faster than the lean medium! Now I’m confused. Both bottles of medium are a bit old. Could that be the reason? Anyway, I think I’ll take you advice and just paint.

    1. Hi Ronnie, thanks for reading and commenting! How wonderful you have found the joys of oils. I must admit I never really got on with acrylics, but I never say never…
      If your lean layer is dry you should be able to paint over it easily. Absolutely. There could only be problems if you paint a lean layer over an oily layer. If the oily layer is not completely dry (inside) it might get sealed-in by the subsequent layers and cause cracking later on.
      I don’t know what your no.2 medium is but it might have something in it to accelerate drying time. Not sure what is going on. I would not change mediums within a painting too much. Find a medium that you like (if you even need a medium – I am quite happy with no medium at all) and only use a tiny bit of it throughout your painting, making sure in the first few layers you don’t use any or very little. And indeed… just have fun and don’t worry too much about it! Happy Painting!!

  6. Hi Sophie, I wanted to thank you for this wonderful blog post (I love your great sense of humor in it too), which answered straight away my question : “Do I need medium to do oil paint?”. I had the intuition that no, we are not obliged to work with medium, but I needed a confirmation to feel good about buying oils. For the quick anecdote, I live since 8 month in a lovely island called Fuerteventura in the Canaries, which is very enjoyable, but there is not a single art shop down here. I only found some oil paint on a chineese shop, without the possibility to buy mediums, which explains my question. So I am happy, I’m gonna begin oil paint despite not having the possibility to buy medium! Thanks a million Sofia. All the best, Nicolas

    1. Hi Nicolas! I am so sorry for not replying sooner. For some reason I did not get a notification for your comment. What a wonderful place you live in. Well, except for the lack of art shops then. Perhaps you should open one, the landscape sure is worth painting there! Indeed, you don’t need a medium so hopefully you are already happily painting away. Best wishes and thank you, Sophie

  7. Hi Sophie and Linda, I too use ws paints of various brands and find them just the same as conventional oil paints when using no medium (my prefered method) and when laying down the drawing and blocking in the darks I dilute with water only which dries quite quickly and feels a bit like watercolour which i guess it is really, then move on to the pure paint. But for fine detail using a rigger I cannot mix a thin and suitable mix, I find that using the ws mediums a hinderance and too sticky and slippery for me, and will not dilute further with water! I think I would prefer to use conventional oils – I have a large collection, but am unsure about toxins, I know I could use toxin free substitute and I may go back to them but for the time being I’m happy with what i use. I run a small class and we use ws paints with quite a bit of success and certainly the clearing up after is less messy than otherwise it would be. Really enjoy reading your posts Sophie keep blogging!

    1. Hi Nigel, thanks for commenting on this post. I am sorry it took me a bit long to respond, I’ve been away for a few days. Well, that’s my excuse anyway. 😉
      It is wonderful to hear your experience with water-soluable oils, I am sure that will be very helpful for readers!
      As for conventional oils, I just wanted to ad that you don’t need toxic materials to be able to paint with conventional oils. The paints are generally not toxic (except for the cadmiums etc but as long as you don’t eat it you should be fine as there are no vapours etc) and if you don’t want to use turps or white spirit you don’t need to as there are plenty of alternatives. I’d be happy to write a blog post about painting without toxins! Hope this helps, happy painting!

    1. Hi Sara, thank you so much for reading my blog and taking the time to comment! It is great to know you enjoyed it. But ooh, an oil painting itch! Well, you cannot ignore that! 😉
      If your old paintings are not varnished there is no reason why you could not paint over them. I would perhaps wipe them clean first with a tiny hint of solvent on a cloth; just to remove old dirt, dust and grime. That way your new layers of paint will adhere properly. If the paintings are varnished you should really first remove the varnish to make sure of good adherence. I hope this helps! Good luck! 🙂 Sophie

  8. Thank you so much….you are a doll! My paintings are not varnished and good to know both ways for now and the future!

  9. Am still looking for that “Control Z” function for oil painting…. have you found it yet? Let me know if you do!

    1. Hah! yes, that would be good. But actually… I have found it. The equivalent of Control-Z is a rag. To wipe off. Or if the paint has dried, simply paint over it. I do it all the time. My whole painting process is about fixing mistakes. I am hitting Control-Z all the time….

  10. HI Sophie, this is very helpful and informative! I’ve been painting for a few years and am now selling at a decent enough price to make me conscious of the longevity of my work. I’d been using Liquin until recently, but have now swapped to a Stand oil/Liquin/Turps mix. When I first paint my underpainting, I thin this with 50% turps, to thin it out further. My question to you is, given that oil straight from the tube contains a fair amount of oil (duh!), should it be safe to use it without medium on the top layer of a painting? I have just completed a portrait, but read that you should add MORE rich medium as you advance through your painting’s layers. My common sense would tell me that finishing with pure oil paint would give you the fattest layer?! Please advise if you can, many thanks!

    1. Hi Linnie, thank you so much for reading my blog! I am so pleased you enjoy it.
      As for your question. Well, it depends a lot whether you paint thick or thin. Paint straight from the tube is by default fine to use on its own. I usually paint with just paint from the tube, without any medium at all. Paint from the tube is neither lean nor fat. So as long as you do not paint a leaner layer over a thick fat layer you should be fine. If you do want to paint lean over fat than make sure it had a long time to dry. Since you are using liquin in the layers underneath your drying time will have sped up? So I suspect it is fine, but I have no experience with liquin.
      There is no rule saying you need to add oil to top layers. The rule is to not use wet oily layers underneath something leaner as the wet oily layer will be sealed in by subsequent layers and if not totally dry, will crack.
      So using ‘straight’ paint as a final layer should never give any problems unless you have used lots of oil underneath it.
      I hope that helps. 🙂

      1. Thank you so much for responding so quickly, Sophie. That really helps. As I paint with quite thin layers, I think that I’m probably in the clear. I guess I’ll know for sure in about 6 months’ time!!! Thanks again, you’re very generous with your time and knowledge x

      1. Thanks Sophie! I didn’t think to try zinc white. Funnily enough I bought a tube 6 months ago and never touched it, because everyone recommended titanium. So I just tried it. It’s so nice! I have some MH titanium white too which is not as sticky as the WN stuff so it seems that you’ve helped me to sort out my whites (combine titanium and zinc, or use medium, as you say), my paint consistency and medium “issues”. Thanks! I have lots more “issues” though… 😉 So I will now go and the rest of your blog and we’ll see what else I can learn… Ps. Love your paintings. Pps. you’re near Bristol! I used to live there (university, Clifton, Redland)… best place in the world, except Bath of course (home town).

      2. Cheers Chris. Zinc white is not recommended on its own but some whites come tubed mixed. Glad to be able to help! And yes – small world. Bath is lovely.

  11. Hi this has been a really good confidence inducing blog.
    I am just going to harp on a little more about stuff here, so do you worry about various pigments having different drying time to be used in different layers when it comes to fat over lean? Eg titanium white dries slowly so is there another white I should use till I get to my top layers?
    Thanks.

    1. I am sorry Jill, it seems your comment did not get through. Thanks for stopping by though, I hope you found the blog post useful!

  12. Well said Sophie. I concur with you on putting off using oils for a long time. This is true of my practice. When I finally went for it, I found myself learning simply through doing. And getting the ‘feel’ of it. I also attended courses with professional oil painters and this has really helped. All, I found, use oil intuitively (as I used and found out about acrylics). There is no substitute for the DOING. Generally, I’ve discovered cold wax because I like my paintings thick and matte. And I’ve also discovered I like dropping pure pigments into the layers. This has all been through trial and error. Love your blog post. Thankyou.

    1. Hi Lesley, thanks for your comment! You are so right; doing is what gets you further and what makes you find out what works for you. You mention some great ideas to try! Thanks!

  13. Very nicely written…Art should be done with a free mind and i believe in the same thing rather making it too complex to understand. Lot of people fear starting with oil paints just coz of this, i am glad you wrote this article….l have just started with oil paints and loving it , this article was like a breath of fresh air after going through some technically correct articles…Thankyou 🙂 Do share some more tips …..

  14. Thank you Shruti! Really pleased you liked my post. Do hang around or sign up to stay up to date ong more posts.much appreciated. 🙂

    1. Hi Michelle, thanks for contributing! Great point. I have heard of Spike Lavender Oil as a substitute for turps and it sounds like a great idea. Mind you, although it is not considered toxic as such, it is apparently still a good idea to keep the bottle closed and avoid breathing in the vapours too much. I have never used it so know very little about it but do your research and Happy Painting! Sophie 🙂

      1. Hi.
        I couldnt get my browser to leave a comment except in reply to previous comments.
        I just wanted to say thanks for your post. I am getting back into oil painting after about a decade or more away from it. When i was painting with oils previously, my knowledge was minimal and mostly self taught, i just knew i loved oil paints. I didnt think much at all about various brands, let alone pigment numbers, and just used turpentine or some mineral spirit and a bit of linseed oil, and just painted.
        Now, wanting to get back into it, i have done all this research on brands, pigments, brushes, surfaces, blah blah blah, and then trying to think of mediums, it can all be overwhelming especially with the internet.
        After literally months of research (which can happen without a decent art store nearby), i finally just purchased online, 13 tubes of mussini oils (i like glazing a lot and mussini seemed very compelling. Ive never used them.)
        Then came the question of which medium. This post has reminded me i can keep it simple. Since i live somewhere with very hot humid summers, i may add something to speed drying time, as oils could take weeks to dry. Maybe I’ll just stick with turpentine and linseed for the time being, until i decide to try something else.
        Thanks for the reminder that i dont need to get a medium im not familiar with before i can just start the joy of oil painting again. Because you are right. It doesnt have to be so complicated.

  15. Also, i just remembered after posting my last comment, and reading through some of your other articles, that you were one of the first writers i came across when i started researching brands a few months ago. You were one of the first places i read about mussini (among other brands).

    1. Hi Brigid, thank you for stopping by. Mussini is a lovely quality of paint. Their colours are beautiful and many of the paints are transparent so you can make some lovely glazes and scumbles. Thanks so much for your kind words, I am so glad my posts have helped you! Getting back into oil painting can be a bit daunting, can’t it. So glad you found your way and hope you’ll enjoy it! (btw, I often don’t use any medium, and sometimes just some solvent and linseed oil, so yes keeping it simple is fine). Would love to know what your are painting? Portraits, landscapes? Anyway, happy painting!!

  16. I have a confusion here; you said you like to paint thinly, which suggests you like to paint in many layers over time?
    If so I’m struggling to visualise the working process to do this.
    For following layers how do you make them fatter in a vaguely correct ratio? I’ve tried and just end up with oil everywhere!
    Do you add your medium to the globs of paint straight out the tube before mixing or are you adding medium as you go? I basically gave up oil painting cos I can’t figure it out

    I also believe in making art archival cos we invest so much time creating it it may as well last!

    Also I’m glad you mentioned viscosity Cos that’s another issue I could never get the paint off the brush onto canvas with any detail or prescision cos so damn stiff and thick

    Note: my goal is to paint without any solvents cos I have a health issue

    1. Hi Brendan, thanks for commenting! I will try to take the confusion away… 😉 Yes, I paint thinly; there are no big fat brush strokes on my paintings. Although the paint is, in the end, put on the canvas in layers, I do not actually think in layers. I don’t apply a first layer and then a second, etc. I just keep painting. I do not make my next layers fatter either. There is no need. The ‘fat over lean’ rule does not mean you have to add more oil to your layers as you go along. It just means you need to make sure you don’t end up putting fat layers UNDER lean layers as that would cause problems. So I do not add any medium in any of my layers! That is the simplest and safest way of doing things.
      As for viscosity, well I would suggest you try another brand? I find a lot of paint very stiff, but some brands are less so (try Blockx, Vasari, Mussini, W&N). If it is still to thick and stiff then perhaps add a drop of linseed oil and see how that goes. Hope that helps! Do check out my latest blog post on solvent free painting !

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