How do you recreate Rembrandt’s impastos?

We speak to two experts involved in an exciting project to try and mimic the unique formulations Rembrandt used to create his signature impasto technique.

Plenty of mystery still surrounds Rembrandt the man and prolific visual artist. His impasto technique in particular – the methods he used to create a thick, paste-like paint – still leaves experts baffled to this day.

 

As part of our Operation Night Watch partnership with the Rijksmuseum in Amsterdam, we’re attempting to recreate Rembrandt’s impastos and gain a better understanding of how he made his unique formulations.

Three different pigmented impasto paints found in Rembrandt’s work have been selected and are being investigated from different perspectives. We asked two of the people involved in the project – AkzoNobel Technology Manager Gerard van Ewijk and Rijksmuseum researcher Victor Gonzalez – to give us an insight into the work they’re doing. 


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Rembrandt’s exact impasto recipe remains a mystery

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Impastos stand out from a surface to create an almost 3D image

We’re working with the Rijksmuseum to try and mimic his technique


First to answer our questions is Victor.


For those who don’t know, what’s an impasto? 

Impasto is thick paint laid on canvas in an amount that makes it stand up from the surface. The relief of impasto increases the perceptibility of the paint by increasing its light-reflecting textural properties. Impasto is notably present in Rembrandt’s masterpiece, The Night Watch. 

What’s so special about Rembrandt’s impastos? 

Rembrandt was a master of impasto and the first painter to use it during the Dutch Golden Age. What’s fascinating is that he achieved this unique effect by using common materials traditionally available on the 17thcentury Dutch color market, such as lead white pigment (a mixture of hydrocerussite Pb3(CO3)2(OH)2 and cerussite (PbCO3)), and organic mediums (mainly linseed oil). However, his precise recipe remains unknown.

How much do you already know about them? 

Recent research revealed the presence of a rare lead carbonate phase, plumbonacrite, in Rembrandt’s impastos. This provided new clues regarding the binding medium he used, but there is still much to discover. 

What sort of techniques will be involved in this project? 

Model systems are prepared in the Rijksmuseum’s Science Department, before being analyzed using multiple analytical techniques. Rheology measurements are being carried out in AkzoNobel’s laboratories.

What are you hoping to learn? 

We hope to gather new information on the exact (organic binder/inorganic pigment) ratio that Rembrandt used to obtain the texture of his impastos. We also want to investigate whether Rembrandt chose a pigment with specific characteristics (notably the particle size). The final objective is to get closer to the actual recipe used by Rembrandt centuries ago. This information would give us a route to the long-term preservation and conservation of Rembrandt’s masterpieces. 


Now it’s over to Gerard to explain AkzoNobel’s role.


How is AkzoNobel helping and what expertise are we bringing?

New paint formulations are made and tested in our labs every day. From the thousands of available ingredients, our experts choose candidates that could give us the desired results and then test them in a structured way. That’s the kind of expertise we’re bringing to this project – knowledge of many raw materials, vast experience of paint-making and experimental design. It’s all about working out what paint variations need to be made and what tests need to be done to get the answers you’re looking for.

We also have experience of measuring many aspects of paints and using dedicated equipment. A central aspect of the impasto project is rheology, in other words, how does the paint apply itself and how thickly can it be applied without sagging? We frequently use state-of-the-art rheometers to measure rheology in all its complexity. I must say, however, that impasto paint is very different from what we normally measure. But that makes it all the more exciting, because we can learn from this project as well.

 

What do you expect the biggest challenges to be?

By far the biggest challenge will be making choices. We want to figure out what paint composition Rembrandt could have used to make his famous impastos. But there are so many possible ingredients and ratios he could have used, that we might end up having to make thousands of test paints to find the answers. So we need to make smart choices to reduce the number of variations. By combining our own raw material experience with knowledge from historical literature and information from chemical analyses on Rembrandt’s paints carried out by the Rijksmuseum, we can focus on the raw materials that Rembrandt would most likely have used.

 

What can AkzoNobel learn from this project?

It will certainly extend our own experience with paint rheology, because impasto paint is so different from most of our products. It will also be inspiring to see what paint ingredients were used in Rembrandt’s time. Many of these ingredients were natural materials, such as linseed oil, egg yolk, natural gums and resins. Because of the renewed interest in green materials, it’ll be fascinating to see what was used centuries ago. Maybe it will spark an idea about how we can use these natural materials in modern paints. The project in general is very inspiring as well. I never realized Rembrandt was a pioneering paint formulator, he must have experimented before he could make the impasto paints that he’s so well-known for. Obviously we can relate to that drive and passion for making innovative, unique paints.



How do you go about restoring one of the world’s most famous paintings?

We asked some of the experts involved in Operation Night Watch to explain what will happen now our historic partnership with the Rijksmuseum is underway.