I’ve been studying lighting and video/photography since the last post. At that time I was sure I had found the reason for the lack of red in the recorded video and photographs of paintings. Firstly, I was taking a ‘white balance’ reading from the blank canvas, assuming it was white. But there’s white, and there’s white. Taking a white balance reading is done to measure the colour of the light and allow the camera to deduct this from the image, giving a photo without a colour cast. Its essential that a pure white surface be used and this was the problem. A blank canvas is not pure white. Mine was slightly cream in colour. This meant the red and yellow (cream) were factored out by the processor in the camera. But this was only part of the problem. Continue reading
As any blogger who tries to upload photos or home made videos knows, what you finally see on your blog page never quite looks like what you intended. I constantly have trouble trying to get exposure and colour balance right on the photos and the video. I use the same lights, camera and computer software and still the difference between still photos and video can be enormous.
The exposure is simple, or should be. If the viewfinder is filled with an image of the blank white canvas, automatic exposure will underexpose the image. This is because the camera is programmed to find the average light reading and record it as an average. But the white is not the average. To find correct exposure I take a manual reading from a mid grey card, this is an average. When the white canvas is then placed in front of the camera, with this setting, it will show an overexposed image, that is, a pure white canvas. By the time the painting is finished, if there are equal amounts of darks and lights in the painting, the exposure is indicating correct exposure. If it’s a dark painting it will appear to be underexposed and if a bright painting it appears to be overexposed. This is OK, as dark paintings are supposed to be dark and light coloured paintings light. When viewed on a computer screen, in Photoshop or web browsers, the brightness of the screen or the room lighting where the screen is viewed will affect the apparent brightness of the picture.
Alexander made a comment, on the ‘Dollardstown Wood’ post, about the darkness of the photo. He was right. I had edited the photo in Photoshop in a darkish room. It looked OK to me at the time but when I read Alexander’s comment, I had a look at the post and the photo was, indeed, too dark. He adjusted the exposure and included a link to the photo (here). This brings me to the other problem with photos – colour balance. Although the exposure was correct the colour balance was too red.
I use iMovie to edit the video because its fast and simple to use. I set the colour balance using the white blank canvas. But still the video always looks a little too red. The still photo (at the start and end of the video), has the same colour balance and is close to the actual colour of the painting. But when placed into the video the colour is altered towards green. There are video editing facilities in iMovie but these are too crude to make the fine adjustments needed. To add further to the mess, YouTube compresses and causes further colour changes which are totally beyond my control. I archive the original video until the technology improves to allow a more accurate representation of the painting. Some day in the near future, hopefully, I will be able to make available the full 1 to 2 hour video. For a beginner in painting this might be useful.
Here’s the video. There is more info on this painting in the previous post.