Before any work can be done, a painting repairer must conduct a thorough visual examination. Whatever you bring to me for restoration, I will spend a significant time looking at it and I will end up knowing your painting literally inside and out.
There are a variety of ways I can use to look at your painting, and each one contributes to an overall picture that will tell several stories.
- What type damage the work has suffered and to what extent, along with any previous attempts to restore it.
- The technique with which the artist handled the paint – clues that will inform the decisions and actions I will take as the painting’s repairer.
- What is happening below the surface of the paint – details which sometimes reveal the development of the work from its underdrawing, or a signature that has been obscured.
There are six means of visual examination that are most commonly used – it would be rare that I would use them all, but the first three discussed below are the most basic and often the most revelatory.
The Naked Eye
I cannot stress how crucial it is to me as a painting repairer to stare at a work that needs my attention. This part of the process is like becoming acquainted with a patient and careful observation should never be rushed. Nor is it a one-off event – over the weeks that I spend with your painting, I will pause many times just to stare at it.
Raking Light
Another very basic visual examination involves looking at the painting in raking light. I will examine the art work in a dimly lit room with a light source that I point across the surface of the painting at an angle. It creates the effect of causing the light ‘to rake’ the surface.
With this light I will be able to view the paint surface and its support. I’ll see any cracks that were not obvious to the naked eye. I’ll get a view of the cracking pattern and I’ll be able to see the depth of the paint layers. Not only does raking light reveal the artist’s painting technique, it also illuminates the paint ridges. I will be able to assess how sharp these ridges are and that will give me an indication of the painting’s overall condition. Sharp, prominent ridges are only present in paintings that have not been pressed or damaged.
Transmitted Light
Transmitted light is the third basic method that requires no equipment beyond a light source and my eyeballs. Sometimes called ‘the poor man’s x-radiograph, transmitted light simply involves holding your painting up in front of a light. I’ll be able to see through the canvas, and damaged areas will appear lighter whilst areas that have been previously restored will appear darker.
This examination can also give me an idea of the build up of paint layers, and sometimes it can even reveal an underdrawing or underpainting.
Ultraviolet (UV) Radiation
When it is necessary to go beyond the visible spectrum I would start with Ultraviolet Radiation (UV). When I expose your painting to a UV light source I will be looking for those organic materials like varnishes, some pigments and paint media that fluoresce visibly to the naked eye. This is a particularly revealing exercise when it comes to previous restorations. I’ll be able to spot the retouching which will appear as purple or black spots, and the darker the spot the more recent the restoration.
After a surface clean, UV light will also show traces of natural resin varnishes – a good way to date the work since these were used primarily up to the 19th century. I might even get clues to the pigments used: the organic pigment of madder lake fluoresces bright pink, and cobalt or ultramarine will appear as pale blue.
Infrared Radiation
More secrets can be revealed if I use infrared radiation to ‘look’ at the painting. Our eyes can’t detect infrared so the image has to be translated into something visible. The near infrared range (NIR) can pierce through the surface paint to reveal underdrawings or underpainting.
X-Ray
Once we have ‘looked’ at and through the paint, it can be helpful to look through the support. To do this I would x-ray your painting. As x-rays pass through solid matter, they change shape and that change is recorded on film or digitally. The higher the atomic number of the material the more it blocks the path of the rays. The lower the number the more rays pass through to reach the radiograph generating a darker image.
I will be able to see information about the painting’s support: nails, joins in panels appear in the x-ray.
In works up to the 19th century lead white was the most common white pigment, and as lead has a high atomic number, I would expect to see lighter areas where lead white has been used. This can reveal changes that the artist made, and it can identify different techniques implying different hands at work on a painting.