Photographing impasto and textured paintings

Chris's Reflection examples: Left- highly textured paint and Right canvas thinly painted, giving unwanted reflections

I was delighted to receive a complimentary email by artist and photographer Matthew Lee (see his beautiful landscape paintings here http://www.matthewleestudio.com/landscapes), commenting on my Kindle book 'Photographing your own artwork', a simple guide for artists on how to photograph 2D, 3D and reflective art, without much photographic experience. 

Matthew then went on to tell me of his frustration of photographing textured paintings, such as impasto oil or acrylic artwork. This rang a bell with me as I'd just done some museum records where I had the same problem. The picture above shows two examples in limited areas of two paintings. I'm fully in agreement with him that often the best option is to photograph in diffuse bright shade. You get an even illumination of of your picture without directional light highlighting certain strokes. If the painting is small, you could even try a light tent. But sometimes you cannot practically do this, or it still doesn't work to bring out the best in your picture. In this case. the general recommendation is to use linear polarised filters on the lights and a circular polarising filter on the camera. 

An aside on the circular polarising filters used for cameras. They are actually linear polarising filters on the front (the filter face closest to the subject) with a circular polarising filter or waveplate on the back (the camera facing side). This construction is essential for the camera to be able to autofocus and judge exposures. For the photography itself, they act as linear polarising filters. There is a great explanation by Bob Atkins here: http://www.bobatkins.com/photography/technical/polarizers.html).

Basically, linear polarisation filters are placed over the lights, such that only polarised light is passed through, that is in the same plane as the picture. When the circular polarisation filter on the camera is rotated, a point will be reached where any reflected light/glare is extinguished and the picture becomes much clearer. A full explanation is given in the Cultural Heritage Science Open Source article here: http://chsopensource.org/2013/02/27/polarized-light-photography-for-art-documentation/

Note: If you are going to use polarisation filter, you also need to recalibrate your white balance for the new conditions (filters on lamps and camera).

However, as Matthew commented to me, this can actually result in your image looking more contrasted (ie punchier) that the real life original, presumably because you also remove the faint reflections on the rest of the painting! 

The image can also lose its impact and appear flat, precisely because you have reduced those reflections that give it it's dimensionality and depth. You can address this by slightly adjusting the rotation of the filter on the camera, such that you get just a bit of light from the reflective surfaces come through - something I do occasionally when using polarised light and photographing through the microscope.

It is at this point that we have hit the usual problems that we photographers experience with any photography and reproduction, :

• What you see is different to what the camera sees/records.
• What is displayed on your screen is dependent on your device and will be different to what the camera records.
• What you have printed will differ from what is displayed on your screen.

You can try to minimise these issues by:

• Including a standard colour scale or similar with the painting when you photograph it.
• Calibrating monitors and printers (or having detailed conversations with your professional printer with the original present).
• Gentle editing in photo software to at least try and match the digital or printed copy with the original as best possible.

But ultimately, it comes down to your judgement on how close your edited digital or printed copy looks like the original! I think that if you look at Matthew's pictures, he's done a pretty good job!