Tuesday, February 07, 2017

More Observations on Photographing Art

I have previously hinted that photographing art might be superior to using a flatbed scanner (well at least the ones built into most multifunction printers). Well I now have a strong case to conform this suspicion. I Have been working on a series of mixed media painting I’ve called the “Summer People” for my larger Endless Summer Project. Whilst I have left the people blank (they are only temporary visitors to the beach) I decided They need to have coloured clothes, and fluro colours are still popular with the summer people. However when I scanned these I was amazed… The fluro colours were flat and very pale. I’ve been looking for an explanation about the direction of light or quality of the light source but I have none to explain this observation. Taking a Photograph the same painting (images on the right below) in daylight the colours are much truer including the non-fluro ones.

Scanned on flatbed scanner Photographed Art WorkScanned on flatbed scanner Photographed Art Work

My Studio set up with the copystandThe main advantage of a flat bed scanner is it (in theory) avoids dimensional distortion, such as non paralleled edges produced when the camera is tilted. I did make an old fashion copy stand out of an old enlarger mounting and can connect my canon camera to my studio computer in tethered remote live view mode (see below). The image is upside down here because of the way the camera is mounted on the stand and because the painting is facing me. I could fix this by putting the painting upside down on the table top or just as easy fix in while post processing in lightroom, I can also focus and control exposure from the computer and once I have every thing set up just slide the canvases one at a time check focus and exposure and click. Its actually faster than loading a scanner closing the cover and click then waiting for the scan, Looking at the preview screen doing adjustments (like rotation) and loading the next canvas…

Remote Live View screenI also need to be careful not to use a zoomed in or wide angle lens, which can cause barrelling (curved rather than straight edges to the canvas) A focal length between 50 and 70mm on my crop sensor canon avoids distortion so I have to adjust the camera height up of down to best frame the picture. In this case I lifted the copy stand onto an adjacent counter top.

Another issue with using a camera, is there is less control of the light source and colour cast can be common. I prefer to only photograph art (and in fact only paint) in daylight. Not direct sunlight but a strong diffuse light such as a window. Even so the colour of the room and its contents will affect the light so it is also wise to consider white balance. By taking RAW format this can easily and well adjusted in post processing. I therefore take a calibration photo using just a commercial colour wheel and one of my notan (greyscale) cards.

Original Photo of Test ChartsAuto White Balance in Lightroom

In this case the test is a little “warm” but may be acceptable. I use lightroom and it has a very decent Auto White Balance, in this case it is colder and more clinical, but better colours and grey scale. You can manually adjust the degree of correction but I’m happy to go with the auto correction. Further light room lets to refine the adjustments on one image and then copy that to all others captured at the same time.

I prefer leave plenty of remove on the margin to allow for trimming later and to individually crop and rotate each picture (again its easy in lightroom) but if you are copying a lot of items the same you could put masking tape as location makers and then have the cropping automated as well.

I am pleased. Using my DSLR canon camera, mounted on my homemade copy stand and tethered to my studio computer, I can reliably and quickly get superior copies to those achieved with a flat bed scanner. By also taking a calibration shot, and photographing in RAW format and then post processing in lightroom, I can also automated white balance and minor exposure adjustments across a whole series of images. Giving me much better and consistent set of images of my art to post on-line.

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