Showing posts with label tether. Show all posts
Showing posts with label tether. Show all posts

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 confirm 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 screen
I also need to be careful not to use a zoomed in or wide angle lens, which can cause barreling (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 a 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 lightroom lets to refine the adjustments on one image and then copy that to all others captured at the same time.

I prefer to leave room 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 fill the frame and 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.

Wednesday, October 05, 2016

Experiments in sketching and recording sketching photographically

2016-10-05_21-36-05_HDRI have previously played around with a web camera to record myself sketching, but sketching is an ultra slow process compared with normal video. So I got as far as figuring a time lapse approach would be better but lost interest trying to do that with the webcam software.

Today I figured I’d try again using my Canon EOS on my homemade copy stand tethered to the computer. I have previously mainly tethered via lightroom, but using the EOS utility from canon has way more controls, including a nifty live view and a system to use a small square controlled by a mouse for focus (not unlike taping a touch screen on my phone to focus on a specific part of the screen.) I was impressed with the results and definitely have a new documentation toy to play with.

#279 IMG_0063_Tonal_Sketching

Tuesday, May 24, 2016

CreativeSpaces :: Automating the Copy Frame

Placing my sketch book on the floor & copy stand on tableEarlier in the year I modified a small enlarger stand to become a desktop copy frame. I love it and use it often. However one tiny draw back compared with a conventional desktop scanner is you have to wait, take the card to the computer and load it before you see the scan in detail. Not a big hassle but can mean you need to go back and re-photograph some works if something was not quite right.

eos utility remote control panelI had an A3 sketchbook full of quick life studies and figured it was time to automate things. With the Copy stand on a desk and the sketch book on the floor, it was easy enough to get a good photo. Also I had previously run the canon tethered through lightroom but not everything on the camera can be adjusted so I when back found the original CD that came with the camera and reloaded the EOS Utility program Live View Windowwhich among other feature (such as uploading photos from the camera) allows you to set ALL the controls on the camera. It also can work in a live view mode to check lighting and exposure. Perfect for what I wanted.

So I can put the live view & remote control on the big screen in the studio and took the mouse down to the floor and control everything from there as I turned the pages in the sketchbook, click, turn the page, click … I powered through the 45 pages of sketches in less than 5 minutes (actually faster than I could have scanned smaller pages on my desktop scanner)

an example scan