Hello, I was just wondering what would be the best way and easiest to scan canvas paintings. I have read some tutorials but the only problem I have is the size of the paintings and the customs sizes they are. If anyone can help I would greatly appreciate it thank you in advance.
Normally artwork on canvas are done with something like a drum scanner at a professional print shop. Other than that, I've heard of large scale canvases being professionally photographed in a studio under quality lighting, sometimes in sections and then digitally stitched together.
Maybe somebody else can advise further. If you have a tripod and a good camera, you could try the second route yourself.
I can tell you from experience, photographing artwork properly is not as easy as it sounds. It's a great way to capture your large canvases digitally but it takes great care. Here's some things I've learned:
1. Painted canvases are rarely uniformly reflective. Some paints/colors absorb light more than others, some paints/colors reflect light. Also, the amount of paint applied to the canvas will affect reflectivity. The upshot of this is that paintings will tend to have hot spots and flat spots that are difficult to predict and manage. One thing you can do is spray you canvas with a lacquer fixative. You can choose the finish you want according to your preference (glossy vs matte vs semigloss). The benefit is that after spraying a few layers, your canvas will be uniformly reflective (proper spraying technique is also something to watch out for, but that is a whole other topic.)
2. Photographing artwork requires very careful lighting. You might not believe the huge affect even the smallest differences in lighting makes on the way your painting will look through the camera. My best results occur when I set up two main lights at equal distances from the easel (each about 15ft away) at a pretty obtuse angle so that the light skims across the face of the canvas. I make sure the lights are feathered into the canvas so there is no hot spot and one light source falls off into the other. I have found this to be the most even lighting scheme and the one that produces the least amount of glare. Experiment with your own lights and equipment, but lookout for glare and hotspots and fall off that makes areas look too dark. Some photogs I know shoot with the light straight on and heavily diffused (with netting). That might work for you too. You can also try shooting with the art inside a light box (which you can build out of translucent paper and a wood frame), but that is a big pain in the butt.
3. Make sure your canvas is perfectly flat relative to the camera. Sounds basic, but you wouldnt believe how easy it is to overlook. If you do overlook it, you'll curse yourself for hours when you go to process your images in photoshop and realize the perspective of the painting is all distorted...
4. Watch out for white balance fluctuation. Because paintings all reflect light slightly differently, there is no easy way to fix white balance in post thru automation: each shot you take will have to be white balance individually.
If you have any questions about this, post and Ill see if I can be of any help.