The realities are that the method by which whites, and in this case, lead whites, were made has changed. Until the industrial revolution lead whites were made roughly in the same way, suspending lead over vinegar in a container and then burying it under horse dung, yes that’s right it is not a typo! The chemistry that takes place is well understood and quite simple in broad terms. First, vapours of acetic acid from the vinegar attack the lead then, the carbonic acid from the warm horse dung converts the white corrosion into lead carbonate. This is a method traced back well before the time of Christ. The Dutch literally scaled up this process and built huge stacks of vinegar, lead, and horse dung-filled containers, which to this day is still referred to as the ‘old Dutch stack process’. For me to be able to recreate the actual white pigment that would have been familiar to Rembrandt and masters of this pre-industrial process is something of a hunt for the holy grail. I have been researching Rembrandt’s lead whites and the old Dutch stack process for many years. So how does it vary from other man-made lead whites?

I believe when nature comes into play, as with snowflakes, every molecule is randomly different, and then every conglomeration of pigment particles on a nanoscale is different. With industrially made pigments every particle tends to be uniform; every bit of colour is deliberately made to be consistent. In our modern world we are “trained” to want bright white things, paper, bleached loaves of bread, white chicken meat, and the list goes on. Consistency matters in the modern world, for example, imagine the frustration if wallpapering a wall to find the colour varied from one roll of paper to the next. How many bright white acrylic primed canvases can you see in art stores around the world? For me this is crazy not only is bright white completely unnecessary it is difficult to paint upon because of the extreme contrast. Most experienced artists start by obliterating this crisp white surface to a more neutral sympathetic hue as a first step.
So, what looks different in the Rembrandt whites? They have a unique texture almost a gloopy, syrupy quality. I try and imagine what he was thinking about when painting his paint. Did he like it? Did he have to fight to get it to do what he wanted? I think not. I think he knew exactly how to make his paint behave.

Many artists of the pre-industrial age appear to have been able to throw wonderful passages of white light as if it magically flowed from the brush. An example is the wonderful painting of ‘woman bathing’ in London’s National gallery. (Photo 1)

Making stack lead white has been a 25-year mission for me. How am I doing it? I start by deliberately hunting the horse fields to gather the freshest horse poop I can. The warm steaming type is best because it’s the most active biologically. I also visit the horse dung piles that are mixed with straw which have been cleaned out of the stables by the people who lovingly take care of these generous animals. Straw is a good addition because it helps aerate the mixture. I then take strips of roofing lead cut them into strips, 6 inches by 24, roll them in a spiral and then place this in a small clay container over a small amount of vinegar settled at the bottom. I then bury the pots in the horse dung. After several weeks magically nature runs its course producing the most beautiful white flakes resembling something more along the lines of the paper one finds in a wasp’s nest, or something made by an insect. The process I find beautiful! This process takes approximately eight weeks depending on the time of year and other weather variables.

What does the pigment look like once it is washed of impurities, ground by hand with pestle and mort and then ground in linseed oil? Firstly, the colour is that of a soft gentle non-brilliant white more like the colour of parchment, soft and subtle. The other fascinating observation compared to an industrially made lead white is in the handling quality. When the paint has been left standing and one takes a pallet knife to it and starts to manipulate the paint, at first it is very short and produces only abrupt wisps of paint.

Here you can see the stack lead white, which has been standing is thick enough to support the weight of the pallet knife.

If you manipulate the stack lead white further for a few seconds, the paint starts to become what seasoned oil artists refer to as “ropier” and produces long dragged wisps of paint below.

I am very proud of my stack lead white as it is what I envision Rembrandt to have used as his white oil paint. My output now is very limited due to the labour-intensive process.

In addition, I am very proud to include these quotes by the well-known American artist David Leffel

“In all these many years I have been painting, which is synonymous for me with studying the art of painting, brushstrokes and paint quality have been essential concerns. The quality of Rembrandt’s white has always been a source of fascination. As Mr Michael Harding has already stated, “his whites cannot be simulated with any white commercially manufactured today.”

Try as I might—adding various mediums to my tubes of lead white, as well as grinding my own lead paint—I could never produce a white which would enable me to achieve the paint quality I sought. And now a new door is opened—stack white! This white allows an artist—any artist—long limpid descriptive brushwork, brushstrokes that reveal the workings and understandings of the mind behind the hand. The long supple quality of stack white that allowed Rembrandt the freedom and expressiveness that enthrals us to this day is, at last, at hand. As with all of Michael’s colours, quality and integrity are in every tube.” – David Leffel

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