René Gerritsen: Going Deeper at a Higher Level

By his own account, René Gerritsen was born to be a photographer. Like many artists, he was helped to build up his professional skills by his father's expertise. However, while his father was a well-known professional photographer in the years after the Second World War, capturing the iconic celebrities of the Netherlands of his day, René's aim was to convey a deeper picture. Indeed, he was not even sure that he wanted to follow in his father's footsteps. His career began with the Nikkormat camera he received for his 18th birthday.

Later, René enrolled at the School of Photography and Photonics, where he studied the spectra of radiation, wavelengths, UV rays, X-rays, and heat, radio and sound waves. The school gave him an excellent foundation, but in his words, “only after we put our knowledge into practice do we become specialists.”

After his studies he worked at the Netherlands Institute for Cultural Heritage, known today as the RCE. It was formerly called the Central Research Laboratory for Objects of Art and Science. It was founded in 1960 with the aim of carrying out research into the deterioration of works of art and into what can be done to halt these processes. The institute had several different studios, where experimental restoration work was carried out on iron, paintings, ceramics, paper, wood, furniture and so on. It was here that René specialised in the techniques required for art research.

Working in the darkroom, he was full of energy and always ready to take on more work, so he was given more. He had the opportunity to travel with the equipment and to work in museums or, when the situation required it, in people's private homes. All of this was a great foundation for his private practice, while he mastered the tricks of photographic research.

The sector is still growing today, in step with the rising value of works of art. Authentication is also critically important when establishing the value of works. Art research can also determine whether a work has been damaged and whether attempts were made to repair it, and it is even able to reveal the identity of the artist.

“The secrets and questions surrounding an artefact can make a big difference to its value. If someone goes to an expert and asks, ‘Is this a real Rembrandt?’, it makes a big difference whether the work was made by the Master himself or by one of his pupils. The demand for artefact research is growing steadily along with the advance of technology.

Initially, film sensitive to infrared light was used to see through layers, such as fog and clouds. It was soon noticed, however, that infrared radiation can penetrate certain layers of paint in paintings. For a long time, film was the only way to reveal the drawings beneath paintings. In the 1960s Mr Van Asperen de Boer developed his so-called “infrared reflectography” (IRR) system. This technology provided much more information about the drawings hidden beneath paintings and about the various layers. When the first CCDs were developed, it was observed that these digital sensors are also sensitive to infrared light.

However, the CCDs developed for cameras used in normal photography were a problem because of their infrared sensitivity, so I placed an infrared-blocking plate over the CCD. By removing this infrared-blocking plate from a DSLR, I obtained a good alternative to the infrared image-capture devices available at the time.

While doing infrared photography, I was also doing art reproduction photography. In 2007 I invested in a Leaf Apus 75, because some of my clients – mainly museums – required a higher quality than I could achieve with my DSLR camera. I was satisfied with the Leaf Apus, as it proved to be one of the most colour-neutral cameras for art reproduction purposes, thanks to its high degree of colour fidelity. Recently I decided that I wanted to raise the standard of my work to a higher level. I was surrounded by freelance colleagues who had achieved enormous success with their high-resolution cameras.

So it was that I went to the “Eyes on Media” team to talk to Dick Jan van den Berg and Rob van der Linden about what could help me step up to an even higher level. I had already heard then that I could achieve high resolution with the Hasselblad, but the problem with multi-shot cameras is that they require a strong, stable platform as well as a very precise flash system of exactly the same power and light temperature. So I would have had to invest in lighting and flashes. With this in mind, and given my experience with its colour depth, I chose the Leaf Credo. Then, looking through the brochures, I discovered that there is also a wide-spectrum version… which I had not known about until then.

Since the Leaf Credo 80WS comes without an IR blocking filter, which is replaced by a glass filter, this made me curious. The question arose in me: if there is a “back” with no filter, would it be possible to take “normal” images with it as well? That was when I noticed that the lens removed from the back, which is sold as a separate item, can be put back, so that the camera takes pictures in the “normal” way and can be used for excellent reproduction work.

My 80-megapixel Leaf Credo proved to be the best in every respect. In this way I can record almost the entire spectrum of the different kinds of radiation with a single camera. True, the infrared mode registers a narrower range than an IRR system could.

The greatest challenge I faced was how to achieve the greatest extension together with the highest resolution. Of course, it would be very good to have a system with which I could extend the bandwidth in small steps from 700 to 2,000 nanometres. If we narrow the bandwidth, we can show which part provides the most information. I tried to work on this with custom-made infrared lamps with different wavelengths. Now, in cooperation with a physicist, we are working on a “high-end” infrared scanning system that we are developing specifically for this purpose.

Another very useful feature of the Credo is that I can use the same flashes for both infrared and normal photographs, and then put the two together to obtain so-called “infrared false-colour images”. This method makes it possible to identify different pigments that have exactly the same shade, thereby making retouching work possible with a degree of precision that would no longer be perceptible to the naked eye.

A further advantage is that it can take two-minute exposures, which is very important in UV fluorescence photography. This is a process that makes it possible to read the very top layer of a painting. It is very important for restorers, because it shows the retouches, the damage and the condition of the varnish. So with the Leaf Credo I can provide excellent quality to my clients – who are mostly private collectors, dealers, art historians, restorers and museums.

I am a photographer specialising in science. I am not a scientist or an art historian, but I can provide reliable information to my clients about what I see. The technology gives me the insight that my clients need in order to reach conclusions. It is a process full of challenges and excellent results, for which the Leaf Credo 80WS is an outstanding tool.”

René Gerritsen's website

Leaf Credo WS specifications (EN)

Leaf Credo further information (EN)