With flash in a skew angle
Photo taken as described
Making good photos of artistic paintings is not a point-and-shoot activity.
But neither does it need to be a professional task requiring expensive requisites and massive preparations.
The main problem is that you cannot use the speedlight of your camera. If you do, you will either get a very 'beautiful' photo of the flash from your speedlight, or you will need to take the picture at a skew angle resulting in distorted proportions of the painting. See the examples to the right and you will know what I mean.
This gives you another problem: Now you are short of light with a color temperature suitable for your camera/film.
The solution is simple: Make the photo as an outdoor shot. But not in any daylight condition. You need to select a day of overcast sky, i.e. no shadows. Preferably a day during spring. If it is not summer or if you are far from Equator, make the photo at noon in order to get enough light.
Now for the photo itself:
Place the painting on an easel or in a chair. Make sure it does not move.
Place the camera in front of the painting, preferably on a tripod.
The distance depends on your camera lens. In general, make the distance as short as possible. If you have a fixed focus camera, a distance of some 2 m. (6 ft.) is appropriate. If you have a zoom, adjust it to some 50 mm. or equivalent
Now to the most delicate part: Your camera needs to be placed on a line perpendicular from the center of the painting. In practice this means that - through the lens of your camera - you should see the lines of the picture frame as absolutely horizontal and vertical. This may take some adjustments of the tripod and distance, but do make yourself the favour of doing this right.
And now: Shoot!
It may take a couple of attempts to do this right, but it is not nearly as complicated as it sounds.
P.s.: A bit of advice regarding digital photos. If you are able to take the photo in a loss-free format (usually TIFF), do it. You can always convert it to JPEG or other compressed formats after you are through with adjusting size, colors, cropping, sharpening etc. If you do not start with a loss-free format, the final result will be inferior.
Web Photo School has a brilliant lesson in photographing paintings and drawings with lamps: www.irphotoschool.com/lessons/e20artwork/e20artwork.php
The layout of this page has been prepared using Cascading Style Sheets (CSS). If you see this text, your browser probably does not support CSS. I have used some effort to ensure that all the contents can be displayed in old browsers, but the layout will no longer be visible in browsers that do not support CSS.