Milk of Human Purblindness

Over the weekend I received a flurry of emails from readers wishing to know the brand and colour of milk paint I used on a pair of forest chairs I made last year. I suppose it had to happen one day.

I know, I know, proper milk paint (milk, slaked lime and pigment) has been identified in a number of ancient Egyptian tombs, but it doesn’t follow that it was ever used on seventeenth-, eighteenth- or nineteenth-century furniture. It simply wasn’t! It was far too fugacious.

Seventeenth-, eighteenth- and nineteenth-century house painters applied distemper to the walls of buildings, (which at least employed animal glue as a fixative), but even with its usual top coat of varnish, it too was not sufficiently hardwearing to be considered of any use on furniture.  Imagine the slimy, sticky mess that would result from a distemper-painted forest chair becoming wet.

Of course, the most suitable paint for indoor and outdoor furniture that was both hardwearing and water resistant, was oil-based. North American paint Analyst, Susan Buck, scrutinised many items of Shaker furniture and concluded:

The physical evidence makes plain that the Shakers generally used traditional oil-based paints to paint wooden objects and architectural elements, and recipes containing milk are primarily lime-based whitewashes or exterior paints, not furniture or interior paints.[1]

(Confusingly, Australia’s Porter’s Original Paints states, “Porter’s Milk Paint is a traditional finish, first used in the 18th and 19th centuries on Shaker furniture.”)

British forest chairs were likewise painted with oil paint. The Gillows archives mention sending green paint abroad with a sea captain for the purpose of painting their cargo of chairs upon arrival at their destination in Antigua. By the duration of such a sea voyage, one can confidently conclude the paint was not milk paint!

If you are quite determined to paint woodwork with milk, at least add it in conjunction with oil in a traditional style emulsion paint. Emulsion paint is still far from ideal, but is what the majority of (now faded and flaky) wooden farm implements and machinery was painted with.

Henry Baird published the good oil on ‘milk’ (lime/milk/oil emulsion) paint for architectural work:

In consequence of the injury which has often resulted to sick and weakly persons from the smell of common paint, the following method of painting with milk has been adopted by some workmen, which, for the interior of buildings, besides being as free as distemper from any offensive odour, is said to be nearly equal to oil-painting in body and durability.

Take half a gallon of skimmed milk, six ounces of lime newly slaked,* four ounces of poppy, linseed, or nut-oil, and three pounds of Spanish white. Put the lime into an earthen vessel or clean bucket, and having poured on it a sufficient quantity of milk to make it about the thickness of cream, add the oil in small quantities at a time, stirring the mixture with a wooden spatula. Then put in the rest of the milk, and afterwards the Spanish white.

It is, in general, indifferent which of the oils above-mentioned you use; but, for a pure white [paint], oil of poppy is the best.

The oil in this composition, being dissolved by the lime, wholly disappears; and, uniting with the whole of the other ingredients, forms a kind of calcareous soap.

In putting in the Spanish white, you must be careful that it is finely powdered and strewed gently over the surface of the mixture. It then, by degrees, imbibes the liquid and sinks to the bottom.

Milk skimmed in summer is often found to be curdled; but this is of no consequence in the present preparation, as its combining with the lime soon restores it to its fluid state. But it must on no account be sour; because, in that case, it would, by uniting with the lime, form an earthy salt, which could not resist any degree of dampness in the air.

Milk paint may likewise be used for out-door objects by adding to the ingredients before-mentioned two ounces each more of oil and slaked lime, and two ounces of Burgundy pitch. The pitch should be put into the oil that is to be added to the milk and lime, and dissolved by a gentle heat. In cold weather, the milk and lime must be warmed, to prevent the pitch from cooling too suddenly, and to enable it to unite more readily with the milk and lime.

Time only can prove how far this mode of painting is to be compared, for durability, with that in oil; for the shrinking to which coatings of paint are subject depends, in great measure, upon the nature and seasoning of the wood.

The milk paint used for in-door work dries in about an hour; and the oil which is employed in preparing it entirely loses its smell in the soapy state to which it is reduced by its union with the lime. One coating will be sufficient for places that are already covered with any colour, unless the latter penetrate through it and produce spots. One coat will likewise suffice, in general, for ceilings and staircases; two will be necessary for new wood.

Milk-painting may be coloured, like every other in distemper, by means of the different colouring substances employed in common painting. The quantity I have given in the receipt will be sufficient for one coat to a surface of about twenty-five square yards.

* Lime is slaked by dipping it into water, then taking the pieces out immediately and allowing them to slake in the open air. [2]

I’ll let second-generation paint specialist and historic paint consultant, Patrick Baty, have the final say:

To believe that [true] milk paint might in any way be more efficient than the more noxious conventional lead paint of the past is fantasy.[3]

Jack Plane

[1] Patrick Baty, The Anatomy of Colour – The story of Heritage Paints and Pigments, Thames & Hudson Ltd., London, 2017, p. 41.

[2] Henry C. Baird, The Painter, Gilder, and Varnisher’s Companion, Philadelphia, 1850, p. 97.

[3] Patrick Baty, The Anatomy of Colour – The story of Heritage Paints and Pigments, Thames & Hudson Ltd., London, 2017, p. 41.

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About Jack Plane

Formerly from the UK, Jack is a retired antiques dealer and self-taught woodworker, now living in Australia.
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17 Responses to Milk of Human Purblindness

  1. potomacker says:

    I’ve learned to distrust anybody using the word, efficient, who works outside the field of thermodynamics. I prefer working with milk paint since it’s much easier to clean up and adjust the coloration while on the woodwork. Is that an efficiency? I’ve added calcium powder but I don’t whether it’s the same chemically as slaked lime. Generally I just add the pigments for a solid color. The BLO can then be applied at a convenient time. So is there a preferred term for this finish?

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  2. Hello Jack,

    I have been reading your post for a few years now, and enjoy following along with your shared adventures, views and perspectives. I’m not sure If I have posted here before, but this one caught my eye for a number of reasons…

    I do apologize ahead of time if some of my remarks seem challenging. Short post like this are horrid for being misunderstood and being a bit “cheeky.”

    First I loved the chairs! Great job.

    “…I know, I know, proper milk paint (milk, slaked lime and pigment) has been identified in a number of ancient Egyptian tombs, but it doesn’t follow that it was ever used on seventeenth-, eighteenth- or nineteenth-century furniture. It simply wasn’t! It was far too fugacious….”

    ??? Is the term “milk” a bit out of context in that statement?

    Milk Paint, in the vernacular, is more slang than anything. It’s a casein paint, and comes in may forms and ways of processing these coagulated proteins. From borax, and blood to citric acid and lye…Methods I have only seen, but yet dabbled with…

    I am a bit of a dabbler in many traditional skill sets, having been raised in a household of Artisan and Craftspeople…Including making our own paints with many different formula. As such, I love learning new methods and from “origin sources” whenever possible. Many from folk artisan that have little to do with Academia or “book learning,” and know what they know by oral traditional and a lifetime of experiences…

    As to the Nile Valley and the Middle East in general there are many traditional formulations. Both egg yolk based Tempras…which are the most enduring and oldest at over 7000 years and still vibrant. The Middle East and Asian overall has a very ancient history with casein, oils, mineral, and distemper paints. With a list of modalities to fill many tome. Distemper is not the same as tempras as the former is base on either animal or plant protein adhesives…These paints and their traditional formalationa are an art onto themselves…Most of the paints left in tombs are not a casein but tempera paint as far as I have seen and/or studied…

    I agree about the use of distemper paints not being suitable for many furniture applications…It would be a mess in most formulations. However I’m not certain that I agree that most or all furniture paints were oil based… That hasn’t been my experience both within our families traditions, nor Amish,, Shaker, Quaker, Appalachian and related folk traditions, that I know of? Straight casein was often used in a very simple formulation of casein proteins, and mineral pigment alone…sometimes with a hot lime additive, sometimes blood, or other folk style fixatives. flax, tung, walnut and related lipid based additives can effectively augment casein based paints also for sure. As can the other traditional additives of pine rosin (similar to or just like your burgundy pitch I do believe?), and beeswax, among other “secret ingredients,” and methods of mixing, heating, and aging before use…

    As such I can’t (nor does my experience) agree with what Susan Buck has suggested. The evidence does not “make plain” that Shakers generally used only oil-based paints alone, and Casein paint can have a “drying oil” added in place of the normal water additive to reconstitute the casein proteins…making these an “oil milk paint.”

    As to the “British Forest Chairs” I have no particular knowledge or experience. If the Gillow archives suggest a “green paint” aboard the voyage, it most likely was in a dry state and separate for the the oil and casein powders which would make this…like many…a casein oil paint…Which we use a fair amount of…

    In general, I think (?) we agree on most points, but these recipes for skimmed milk are wanting. Milk paint is really…just milk…mixed in with these ingredients. Try it yourself and you will see the mess it makes. The milk has to be process to remove the casein in the proper way before any effective paint can be made…straight or emulsified with a drying oil and/or other additives…

    Lime Washes, are another topic entirely and neither have a lipid nor a casein added to them…Lime wash in most traditional formulation that I know off and/or have created and used is a true…mineral paint. In the same family (but not as durable) as a silicate paint…

    “…Time only can prove how far this mode of painting is to be compared, for durability, with that in oil; for the shrinking to which coatings of paint are subject depends, in great measure, upon the nature and seasoning of the wood…”

    Considering I have used these for over 40 years, and our family since the early 1800’s I think the formulas (et al) have more than proven long term durability even when exposed to the weather, as long as “touch up” work is done periodically…Our oil based “milk paints” do not have any lime added to them at all. Just pine rosin, beeswax, flax and tung oil with a citrus oil thinner for the first coat to soak in deeply. Needless to say there are countless other formulation, and I learn a few new ones each year…

    Thanks for a great post!!!

    j

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    • Jack Plane says:

      Jay, Thank you for your kind words. Your comments are neither challenging nor cheeky: All (relevant) dialogue is welcome here!

      “Is the term ‘milk’ a bit out of context in that statement?”
      No, the subject is milk paint – MLP (milk, lime and pigment). Like you, I am aware many other paint media have existed for millennia.

      “Milk Paint, in the vernacular, is more slang than anything. It’s a casein paint, and comes in may forms and ways of processing these coagulated proteins.”
      I wasn’t going to respond to this comment, but you may have a point. If ‘milk paint’ has come to reflect any and all water-based concoctions, one of whose ingredients is milk, then we are in trouble!
      If we equate milk paint to timber; recommending someone paint their Windsor chair with milk paint is akin to suggesting they also make the chair (with all its unique tensions and flexibilities) out of ‘wood’.

      “However I’m not certain that I agree that most or all furniture paints were oil based…”
      Nobody is suggesting this.

      “Straight casein was often used in a very simple formulation of casein proteins, and mineral pigment alone…sometimes with a hot lime additive, sometimes blood, or other folk style fixatives. flax, tung, walnut and related lipid based additives can effectively augment casein based paints also for sure. As can the other traditional additives of pine rosin (similar to or just like your burgundy pitch I do believe?), and beeswax, among other “secret ingredients,” and methods of mixing, heating, and aging before use…”
      They are emulsion paints.

      “As such I can’t (nor does my experience) agree with what Susan Buck has suggested. The evidence does not “make plain” that Shakers generally used only oil-based paints alone […]”
      You are misquoting Susan Buck’s findings:
      “The physical evidence makes plain that the Shakers generally used traditional oil-based paints to paint wooden objects and architectural elements […].”
      Susan does not use the words “only” or “alone”.

      “[…] and Casein paint can have a ‘drying oil’ added in place of the normal water additive to reconstitute the casein proteins…making these an ‘oil milk paint’.”
      Again, you are describing emulsion paint, not MLP.

      “If the Gillow archives suggest a “green paint” aboard the voyage, it most likely was in a dry state and separate for the the oil and casein powders which would make this…like many…a casein oil paint…Which we use a fair amount of…”
      Gillows’ paint was pre-mixed:
      “Have sent 2 Windsor chairs in the cabin and 10 ditto in two matted parcels with the legs and rails loose which you’ll to get put together and paint over; have also sent green paint ready mixed and a brush (for that purpose)…”
      Oil-based paint was the norm and is well documented. I referenced the Gillows quote only because it was easily linked to on my blog.

      “Lime Washes, are another topic entirely and neither have a lipid nor a casein added to them…”
      Many traditional lime washes contain milk (amongst other ingredients).

      “Our oil based ‘milk paints’ […]”.
      What can I say? The topic is milk (based) paint.

      JP

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  3. Alex A. says:

    I’m a bit confused, here. Are the products made by the Real Milk Paint Company or Old-Fashioned Milk Paint companies “milk paints” or “emulsion paints”?

    I have used their products for several years (top coated with BLO) and hav found them to be quite durable. I live in a very wet area (high levels of fog) with humidity than early drops below 60% but have not had any issues (yet).

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    • Jack Plane says:

      The Real Milk Paint Co. states: “We make ours from purified milk protein, lime, natural fillers and pigment. Other paint companies choose to use Kaolin Clay as filler. Real Milk Paint® does not contain Kaolin Clay which can be derived from radioactive clays”.
      They go on to say, “Our colors have been derived from more than 15 years of experience restoring and observing antique paint finishes of fine furniture. We developed our recipe in our antique restoration business based on the need for authentic product […].”
      Some of their colours are recognisable and their paint is authentic milk paint, but they avoid claiming it’s authentic for eighteenth- or nineteenth-century chairs and other furniture.

      The Old Fashioned Milk Paint Co. states: “As in originally produced home-made milk paint, we use milk protein, lime, clay, and earth pigments […].”
      This is more or less authentic milk paint too.

      Neither company lists oil as an ingredient, but without the addition of oil, or similar, milk paint lacks the cohesion necessary on chairs etc. to withstand regular use. By top-coating with BLO, you are, in a roundabout fashion, applying the constituents of emulsion paint which is indeed more durable, but not even authentic emulsion.

      JP

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      • Alex A. says:

        So it’s milk paint but not the “traditional” form and therefore avoids the problems you mentions

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        • Jack Plane says:

          Yes, they produce authentic milk paint (the Egyptians would have loved it), but milk paint was not used on Windsor chairs etc. In rural situations, some may have been painted with emulsion paint containing oil, pitch etc. (which would account for the high degree of paint loss we now see on some of the more rustic chairs and other furniture), but by far, the vast majority of chairs etc. were painted with oil paint.

          JP

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          • Alex A. says:

            I’ve not used it on chairs (though my son’s toy chest is frequently used as a seat) but I know some of the modern American Windsor makers use it. One of these days I need to make a traditional Windsor, if only I had time….

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  4. Finally….someone challenging the recent fad of slathering milk paint on everything in the name of 18th century authenticity.

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  5. Hello JP,

    Great response and explanation above to my post…

    I am wondering now if a lot of this is “regional linguistics” as much the actual alchemy of the different formulas. Your in Australia…correct? As such, do you think perhaps the evidence and perspectives might be different to a degree or at least on a spectrum?

    I am in “Shaker Country” here in New England and within easy driving to several old Shaker villages and collections. Old “Milk Painted” objects are ubiquitous from the reference time period all around me, and in the work I do. I would also share, I was raised in a household of “paint makers” of all types. I’ve also been to the Smithsonian, Peabody, and several other period collections a number of times. I’m not sure all the folks style and related Appilachian furniture (my personal interest and style of work) identified that I have seen from the 17th and 18th century where “emulsion paints” (which I take from your suggested writing (??) is meant they are either “oil mixed” and/or have an oil top coat? Some are, many are not, and have endured well.

    I want to understand your perspective more cleary…If you think I am missing something?

    From what I’m understanding about this post is you are (basically) saying that…pure casein paint wasn’t as commonly employed as many contemporary artisan are claiming and/or using on their furniture…

    Is that correct?

    I would suggest then that is in your area only and not here…per se…

    I can say that in my family’s traditions, I would agree with you about there clearly being a choice, as they tended to augment the “Mild Paint” the made with oils either as an additive or an overcoat. However, in the observed collections and countless found objects through New England and Appalachia, or objects brought or seen on restoration benches, I am not sure that is true at all for the reference time period and the region I have referenced…Maybe 50/50 or 70/30…I’m not sure but not most are oil based/coated…I don’t believe that is true at all…

    From a period specific restoration/replication choice. I think there are many formulas to choose from. Following the Burra Conventions standards of ” Like for like, in mean, methods and materials…” a period item (or replication of same) should follow as closely as possible what an original form had on it…Even if less than the most durable formulation. That way a german and traditional patia will form properly… I would note in addition, that some, over there very long life of service, do show signs of having later “oil based” finished added over the older finishes, yet this augmentation is still over 100 years old, and different than the original formula…Not an easy thing to replicate…LOL…

    What I think we do fully agree on…(please correct me if I’ve presumed incorrectly)…that an oil based “Casein Paint” is always going to be superior in durability, and general appearance over time…

    Dwayne (owner of the Real Milk Paint) company is a friend and colleague I turn to often for views on such as discussed in this post. I think he would probably agree with much of what I have written.
    As far as I know, his formulas (there are many) all would meet the standards for most Historic Restorationist and Conservator’s work. I’ve seen his products employed well in several museums for such work, and he can and does just sell the raw casein and other related ingredients if one wishes to experiment with different modalities.

    Thanks again JP for your blog and these types of discussions…

    Regards,

    j

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    • Jack Plane says:

      I don’t wear the ‘divided by a common language’ thing (in this instance) – the confusion/red herring concerning milk paint is a broader issue as both Susan Buck (through scientific analysis) and Patrick Baty point out.

      There are several manufacturers of true milk paint; however their claim to authenticity for use (without the addition of oil) on eighteenth- and nineteenth-century furniture is strongly refuted.

      Milk paint top-coated with oil is not the same as emulsion paint: It results in a spurious sealed, plasticky surface akin to acrylic (latex, to you) paint. I believe at least one manufacturer does actually market acrylic paint as ‘milk paint’.

      Our ancestors knew the shortcomings of milk paint and so added oil to the recipe to improve and stabilise it. This milk/oil emulsion did – and can – create a fugitive, period-correct look.

      That said, oil paint was the first choice for the majority of painted architectural woodwork, furniture and certainly Windsor chairs.

      JP

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  6. “…That said, oil paint was the first choice for the majority of painted architectural woodwork, furniture and certainly Windsor chairs…”

    Thank your of sharing further your opinions on this subject, and viewpoints regarding the period applications of different finishes.

    We agree on most points, yet I will close with the point again that my ancestors are paint makers and users and do not follow at all the complete outline of this current post topic as you see it. Nor do the findings within many museums and private collections reflect it…at least here in the United States…

    I can agree that oil paints (for the most part) where indeed the…desired finished…when possible by most that could get them and/or make them…They absolutely where not always the…”first choice”…neither in my family, nor in the historic record or the artifacts still available for viewing…Not as the original finish applied to them…including Windsor chairs…

    “…Milk paint top-coated with oil is not the same as emulsion paint…”

    No, they are not the same, as the latter can actually be better in many cases…We can agree to disagree on that point.

    It absolutely does not “result in a spurious sealed, plasticky surface,”… if executed well and the proper modality understood…Again thank you for openly sharing your perspectives and viewpoints…

    j

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    • Jack Plane says:

      My pursuit is not to necessarily agree or disagree, but to be historically accurate in relation to seventeenth-, eighteenth-, and early nineteenth-century furniture.

      Neither am I interested in a method or recipe being superior or inferior: The paint I apply to the backs of case furniture, for example, is terrible stuff and a quantity can rub off initially, but for all that, it is historically correct.

      In the context of this blog and importantly, this post, the British and North American authorities that I referenced are recognised and highly respected by their peers worldwide. I have no reason to doubt their empirical and scientific findings. I can’t answer to your experiences.

      JP

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      • JP…

        Your neutrality is to be not only commended, but admired…Thank again for another grand response…

        I especially loved the, ” neither am I interested in a method or recipe being superior or inferior…” I’m afraid that one will stick and have to be used, as it is a great response to many a comment I receive on “why” something is done the way its done…

        Not that I have dug terribly deep, but have you shared someplace on this blog (or else where) your specific recipes for different finishes, or are they propratary to your work? I am keenly interested and would love to know any you would share, including the one you just reference for the, “backs of case furniture.”

        If I may be so bold, and only if you do share these recipes, could you grace us with a post dedicated solely to the crafting of your different finishes, the reference material (and individuals) you yourself deem most apropos to this art and craft, and any related thoughts?

        Please note, disagreeing with you on a “nit pick” academic point or other is both and honor and pleasure, but as I can see from this post, It really isn’t necessarily a pursuit…You are most gracious host and facilitator of insights…

        Regards,

        j

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        • Jack Plane says:

          I touched briefly on one variety of case paint here.

          I keep saying I will release a book revealing my techniques and recipes etc. – and I will, one day. I just don’t know when that day will be.

          Thank you for your candour and input.

          JP

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          • First thank you for the link…

            Next, deep thanks for your blog, as well as the candour and willingness to indulge those like me with your time…

            For me it is a tome on vernacular folk styles of timber framing techniques…both for restoration, and for the current expanding trend in those that wish to build with these modalities. I do hope we both get these books out of ourselves before the great Creator has other plans for us…LOL

            Warm Regards,

            j

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