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Old 07-20-2005, 07:58 PM
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hamsterdance hamsterdance is offline
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Noob Question - fat over lean?

What exactly IS fat over lean? I keep seeing this phrase chanted like a mantra in numerous threads but am still not sure if I understand what it's referring to.

I take it to mean the first layer needs to be thin and watery? What happens if someone paints ALL layers thin and watery? Is that glazing?
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Old 07-23-2005, 03:21 PM
dcorc dcorc is offline
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Re: Noob Question

Hi hamsterdance - first of all, I'm moving this to the main Oils forum, where more people will see it (The Painting from the Masters subforum is only intended for posting threads about study-copies and related - and an archive of our "What's on your Easel" threads )

I'll move it and then answer the question.

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Old 07-23-2005, 03:52 PM
dcorc dcorc is offline
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Re: Noob Question

"Fat over lean" is shorthand for a technically sound method of doing an oil painting in layers.

In brief, what you want is a situation where upper layers on a painting are not less flexible or faster drying than lower layers, because these predispose to cracking - so good practice chooses faster-drying colours in lower layers, reserving use of slower drying ones for upper layers.

Oil paint should be used at somewhere between a creamy consistency at thinnest, up to straight-out-the-tube - never "watery" (using solvent) as you will wash all the oil off the pigment particles by doing so, and there will be nothing to keep them adherent to the surface! (This is described as being "underbound").

All additions to the paint to change its handling characteristics should be made using the smallest additions possible - a good rule of thumb is never to exceed 20% of total additions (and usually, stick to a lot less than that!).

Subsequent layers may change the proportion of solvent to oil in the medium in the successive layers upward towards increasing amounts of oil. However in general the changes that should be made are fairly minor, in terms of total amounts - a lot of the problems we hear about are because people are over-enthusiastic with the amount of medium added, and over-enthusiastic with the extremes of "leanness" and "fatness".

Dave
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Old 07-23-2005, 04:06 PM
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Re: Noob Question

Different paints have more oil in them too and are "more fat" I believe. For instance cereleun blue is way fatter than burnt umber. I wonder if there is a list anywhere. But you do learn from trial and error , as the lean over fat cracks very quickly. I paint in water soluble oils and they dry faster than traditional.
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Old 07-23-2005, 05:23 PM
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Re: Noob Question

hamsterdance,

Let me add a bit to what Dave has stated. Viscosity or "thickness" is by no means an accurate measure of the "fatness" or leanness of a medium.

For example, a medium made with only 1 part of Stand Oil to 5 parts turpentine is not much different than a medium made with 2 parts Linseed and 2 parts turpentine in its flow and "thickness" (viscosity).

However, the medium containing 1 part Stand Oil to 5 parts turpentine is by far a much leaner mixture (quicker drying/less flexible) than the medium containing 2 parts Linseed Oil to 2 parts turpentine, although the viscosity of it is nearly the same.

The medium containing the greater porportion of Linseed oil to the solvent, turpentine is fatter, simply because it contains more oil to solvent--not because it contains thicker oil.

To summarize,....."fat" is not a measure of viscosity (thickness) of the oil--it is a measure of the proportion of oil to solvent. Thicker paint or thicker medium, does not necessarily equate to a "fatter" paint or medium.

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Old 07-23-2005, 06:38 PM
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Re: Noob Question

Thank you everyone. I particularly liked this response

Quote:
The medium containing the greater porportion of Linseed oil to the solvent, turpentine is fatter, simply because it contains more oil to solvent--not because it contains thicker oil.

To summarize,....."fat" is not a measure of viscosity (thickness) of the oil--it is a measure of the proportion of oil to solvent. Thicker paint or thicker medium, does not necessarily equate to a "fatter" paint or medium.


The light bulb finally turned on! I have a 12 color intro set of Holbein oils and 3 of their Duo Aqua oils. The standard oils are very thick and hard to manipulate so I've been adding a bit of W&N Liquin to them to help make them more spreadable.

I even tried scooping out some Liquin and spreading a thin layer of it on the board then following with a bit of Burnt Sienna. The result looked like parchment or tea-stained. I like that antique look.

Other times I mixed the Liquin in with the B.Sienna until it felt like something I could paint easier. I'm used to painting with acrylics so I was thinking I should make the oils a bit less creamy and spreadable (to preserve the brushstroke-ness). Now I wonder if I've violated the fat over lean rule?

Also, I have another question.

I've read in some threads that Holbein and Old Holland represent one way of making oil paints - rather stiff - what I call gummy vs. Rembrandt - buttery. Does one have an advantage over the other? I read a thread where someone said that the stiff formulations create superior blends to the buttery types.

Is this true or am I misunderstanding something?
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Old 07-23-2005, 09:14 PM
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Re: Noob Question

Old Holland oil paint is usually stiffer, because the pigment load is heavier in that brand. That represents more "color' for your money, but usually creates a stiffer paint. But that's OK, because you can always add a medium to make it more managable. Old Holland is good paint, but is quite expensive.

Bill
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Old 09-21-2005, 08:43 PM
Daniel Rigos Daniel Rigos is offline
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Re: Noob Question - fat over lean?

This fat over lean is always confusing me as well. It is making more sense everytime I read something though

I have two questions, first one is when using mediums without solvents following the instructions on this page http://www.budgetartmaterials.com/sofroilpa.html. Basically it is a mixture of linseed oil with stand oil in a 3 to 1 ratio.

Is the idea that you just add more and more medium each layer? Or as there is no solvent does it not matter as much?

Can I keep on using the same amount of medium every layer? I have read that this is ok.

Secondly, if I am using a medium like linseed/stand oil or just walnut oil do I have to use it everywhere on each layer of the painting. Ie, can I use medium for painting certain areas, then use paint straight out of the tube in other areas. Can I keep doing this over multiple layers?

Can I for example do a layer with medium added then start painting with white straight out of the tube on the next layer? Then medium on the next.

Sorry for all the questions, and thanks for any help you can give!!
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Old 01-03-2008, 07:14 PM
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Re: Noob Question - fat over lean?

This is all confusing to me...can a master in here just write it down in black and white.
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Old 01-03-2008, 09:04 PM
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Re: Noob Question - fat over lean?

In a nutshell - if you paint in a process where you paint your entire painting in a day or two (or before it dries) then you don't have to worry about "fat over lean".

If you paint in layers - letting a layer dry then painting another layer over the top - then each layer should dry slower than the layer below. Lean layers (with less oil) dry faster. Fat layers (more oil) dry slower. You don't want upper layers to dry while lower layers are still drying. Thin layers dry faster than thick layers as well. It is really a drying issue.

Yes, certain tube paints have more oil, but chances are you won't know which or be able to keep track. I have never paid attention to this part of the equation, but as others have mentioned, if you notice certain colors take longer to dry, avoid them in your first layer.

Many painters follow this general formula: First layer (or underpainting), paint straight from the tube, thinned if necessary with a little bit of solvent (turps or mineral spirit). Solvent has no oil and is lean. Second layer and beyond: tube paint with a touch of medium (mediums usually being a mix of oil, resin, and solvent - but their oil content makes them fatter than paint out of the tube). Each layer can have equal or more medium added to the tube paint so that it is at least equally fat to any layer beneath.

One way to simplify the process - paint straight from the tube and don't use any medium or solvent. This is what I do and all my layers should be essentially the same fatness (or leanness).

Don
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Old 02-21-2008, 08:55 AM
Easyout58 Easyout58 is offline
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Re: Noob Question - fat over lean?

These explanations have been very helpful to us "noobs". Thanks to all! I have been using Winsor Newton Artist oils and I swiped this from their webpage:

Fast Drying [around two days]:
Permanent Mauve [manganese], Cobalt Blues, Prussian Blue, Raw Sienna, Umbers, Flake, Foundation and Cremnitz Whites [lead].

Medium drying [around five days]:
Winsor Blues and Greens [phthalocyanines], Burnt Sienna, Cobalt Violet and Greens, Ultramarine Blues, Mars colours [synthetic iron oxides], Sap Green, Permanent Alizarin Crimson, Ochres, Cadmiums, Titanium White, Zinc White, Lamp Black, Ivory Black, Pyrrols, Bismuth Yellow, Perylenes.

Slow drying [more than five days]:
Winsor Yellows and Orange (arylides), Quinacridones, Alizarin Crimson.
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Old 01-17-2009, 03:41 PM
Jacques Ataque Jacques Ataque is offline
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Re: Noob Question - fat over lean?

As black and white as possible:

The rule is solely designed to ensure that your layered paintings last centuries rather than months.

It's about the mix you make of your oil paint and other things like thinners and linseed oil.

Lean = less oil in the mix
Fat = more oil in the mix.

You can start with a lean mix, and then later on add a fatter layer.

Never start fat and end lean.

The oilyness of the mix includes the amount of oil already in the oil paint in the tube.

Liquin and other 'alkyds' and 'drying' oils are fatter than thinners but leaner than straight oils.

Here endeth the lesson (It gets more complicated below this line).

----------------------------

I only disagree with Dave in regards to underbinding. He might be able to correct me, but I've not had problems starting with washes, as long as they are subsequently overpainted. And they make a great quick start to establish the tonal values.

----------------------------

Liquin and other drying-modified media and oils are 'leaner' than straight oils because they have modifiers that actually 'dry' the oil faster. Oil paint 'dries' in the same way that iron rusts: it combines with oxygen from the air. If you put a chemical in your oil that speeds this process, it'll happen faster, so your layer will dry faster, so it'll be leaner as far as the archival nature of the layering technique is concerned (see earlier posts in this thread for an explanation of the drying process in layered paintings).

Resins like Liquin are a complicating factor because they are also about the handling: for me, Liquin makes the oil paint handle more like enamel, which I find makes details easier to define but blending and scumbling aren't as straightforward and you get a plasticky, hard shell finish which is less warm than straight oils. I prefer to get sharper details by using more layers. Fatter layers painted over fat layers are easy to get sharp as you like.

----------------------------

Hamsterdance: Glazing is usually defined as painting a darker, semi-transparent, fatter paint over a usually lighter and leaner area. Glazing is often used as a technique in a later stage of a layered oil painting. It has the effect of giving a 'glowing', more colourful finish to your dark areas or coloured areas. If you glaze over blank canvas it doesn't have usually give a great finish: best to start with a leaner underpainting and glaze over it. People often use glazes over an underpainting to add colour to a precise tonal range they have already established in monochrome. Glazes in already dark areas increase a painting's tonal range. The semi transparency makes darks look blacker than black, which allows a more extended tonal range, so the whole painting looks more natural and the light areas look brighter by contrast. Glazing can also be used over scumbling or textured paint to get complex effects - have a close look at work in museums by as many different artists as you can from the 17th century up to the early 20th century and you'll start to see how glazed layers can be used for special effects.
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Old 01-17-2009, 07:04 PM
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Re: Noob Question - fat over lean?

It doesnt necasarrily mean that the first layer has to be thin and watery- it just means each layer should be fatter (less thinned down) than the last.
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Old 01-19-2009, 11:23 AM
Jacques Ataque Jacques Ataque is offline
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Re: Noob Question - fat over lean?

Quote:
Originally Posted by oilpainter98
It doesnt necasarrily mean that the first layer has to be thin and watery- it just means each layer should be fatter (less thinned down) than the last.
I think that the above is possibly misleading. If you start with paint straight from the tube and then paint subsequent layers with added linseed oil (or any other oil) then the paint will be both thinner and fatter than on the earlier layers. If you thin your paint with oil, you are adding more oil which makes your paint fatter.

The standard vocabulary on this forum seems to be:

Lean = less oil

Fat = more oil

Thin = less pigment/bulking agent

Thick = more pigment/bulking agent

It's the amount of oil on each layer you need to control, not the amount of other stuff.
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Old 02-04-2009, 05:55 AM
dcorc dcorc is offline
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Re: Noob Question - fat over lean?

Quote:
I only disagree with Dave in regards to underbinding. He might be able to correct me, but I've not had problems starting with washes, as long as they are subsequently overpainted. And they make a great quick start to establish the tonal values.

And I will. I put in the comment about the issue of paint being underbound after thought on the matter and for very good reason. It is, bluntly, solid and accurate information which any painter inexperienced enough to need to refer to this thread about "fat over lean" would be well-advised to follow.

Paint is "mulled" in order to ensure that the pigment particles are separated from one another and that each particle is coated by an adsorbed layer of oil, which serves to "wet" the particle and bring it into intimate contact with the oil present between the particles. Good contact between the oil and pigment is important to the laying down of a coherent paint-film in which particles are properly enmeshed within the network of polymerised oil molecules formed by the "drying" of the paint. Subjecting the paint to excessive dilution by solvent to the extent of making "washes" will strip off this adsorbed boundary-layer of oil. The resulting paintfilm will be attenuated and less adherent, and more prone to cracking and delamination. Furthermore, assuming that the addition of an oil-out coat, or further less-diluted layers will rectify the situation, is bad practice, as doing so will still not ensure that the first layer is so fully and intimately coated with an adsorbed oil-layer as is achieved by mulling.

Quote:
Originally Posted by Jacques Ataque
Quote:
Originally Posted by oilpainter98
It doesnt necasarrily mean that the first layer has to be thin and watery- it just means each layer should be fatter (less thinned down) than the last.
I think that the above is possibly misleading. If you start with paint straight from the tube and then paint subsequent layers with added linseed oil (or any other oil) then the paint will be both thinner and fatter than on the earlier layers. If you thin your paint with oil, you are adding more oil which makes your paint fatter.

As I've already addressed, don't thin your paint to a "watery" consistency.

If you add more oil to the paint, it will be FATTER. No ifs, no buts, no equivocation. FATTER.

One of the really annoying things about this site is the way that inexperienced people add in further, inaccurate, incorrect, and contradicting "advice" on things that are already well-answered by experienced people, and in doing so, muddle the information again.

I'd strongly recommend that all readers here re-read what I and Bill Martin have to say, in the earlier posts on the thread, as these give accurate information.

I'll re-iterate:
Oil paint should be used at somewhere between a creamy consistency at thinnest, up to straight-out-the-tube - never "watery" (using solvent) as you will wash all the oil off the pigment particles by doing so, and there will be nothing to keep them adherent to the surface! (This is described as being "underbound").

All additions to the paint to change its handling characteristics should be made using the smallest additions possible - a good rule of thumb is never to exceed 20% of total additions (and usually, stick to a lot less than that!).

Subsequent layers may change the proportion of solvent to oil in the medium in the successive layers upward towards increasing amounts of oil. However in general the changes that should be made are fairly minor, in terms of total amounts - a lot of the problems we hear about are because people are over-enthusiastic with the amount of medium added, and over-enthusiastic with the extremes of "leanness" and "fatness".


Dave

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