Although this tutorial is aimed at taking pictures of artworks in general, it will show you how to take photographs of paintings in order to save them in digital format and all that entails, from displaying them in Internet to selling reproductions.
To take these types of pictures, neither a professional camera nor a teleobjective lens and big angular lens are needed. We can work with digital cameras, even with camera phones. It is advisable to use a tripod to avoid holding the camera when taking the picture. Take into account that some cameras do not have flash, zoom or any other elements.
The lighting is the most critical part to handle when shooting pictures. We need a well-lit space with homogeneous, diffuse, one tonality light. Do avoid spaces with different tonalities as they may alter the color of the work you are shooting. Besides, place the subject in front of a background with neutral colors (gray, black or white).
4.1.- Artificial lighting
The more light the better, if is homogeneous and diffuse. It is easier to control artificial light but you can also use natural light if you decide to shoot in a luminous indoor space. If you are going to use artificial light, make sure you illuminate the subject from both sides to prevent glare and reflection. Do not expose the artwork directly to the light.
If we do not have enough light, we can use the in-camera flash (even if the flash produces very harsh shadows and flat lighting). If we use the flash, we can diffuse it by covering it with some pieces of paper).
We can also reflect the light to a white background (white walls, noticeboards, umbrellas) so that the light will be at 45º from the subject. When using the in-camera flash, we will try to reduce the exposure time in order to uniform the lighting.
4.2.- Positioning and framing
To take a picture, we will place the camera in front of the subject, parallel to it and at the same height. The distance from which we have to shoot pictures is the one that allows us to get a good framing and the one that allows us to fill the frame with the subject.
If your camera specifies the focal length, you should change it to a 50mm focal length to prevent distortion of the image. 
If your camera has the ‘mm’ number written on one of its sides, you can easily use a 50mm camera lens. If your camera does not have the ‘mm’ number, you can get to know the focal length with simple calculations. Normally, every camera specifies its minimum focal length that can be 35 mm (common focal length in mobile phones). In this case, if we set up the zoom lens at 1.4x we will be able to shoot at 49mm (35mm * 1.4x), that will serve us because we will shoot almost at 50mm. (If you are shooting with 50mm with a normal digital single-lens reflex camera (DSLR), you will be using an analog 80mm format, depending on the conversion factor.
If you cannot know the focal length you can do the following thing: if your camera has an optical zoom, set the zoom at the halfway point. If you have a digital zoom, set the minimum level.
4.3.- Shooting settings
Although the camera may allow you to set some manual settings, you can also shoot in automatic, which sometimes gives better results. The camera user manual specifies which automatic setting works better for each kind of photograph. 
If our camera has a self-timer and we have a tripod or a place to leave the camera, we will use the self-timer to prevent the phenomenon known in photography as camera shake. Thus, we will not move the camera and the picture will be sharper.
We have to bear in mind that manual and automatic settings are aimed at taking static photographs, so we do not need fast shutter speed. We can modify the aperture diameter as we wish and use a middle one, which will be the best for us to work. A f/8 aperture might be perfect for this kind of photographs.
Please, take into account that if we use large apertures, we could find some parts of the image out of focus. On the contrary, if we use very small apertures, the long exposure time will produce "image noise" or differences in the lighting of the subject.
4.4.- Image file format
We should save the images in the highest quality. Nearly every digital camera can save images in JPEG format with different qualities: we have to choose the format with the best quality and size. Many cameras can save images in RAW format, which uses a lossless or nearly-lossless compression. However, we believe that using RAW format is aimed at advanced users.
If the picture has not been taken properly, it could be due to the following reasons:
5.1.- Image too dark or too bright
If we are shooting in automatic, the photograph may be neither too dark nor too bright. The picture will be too dark or too bright if the in-camera flash is disabled. We should enable the flash to get a proper picture.
If we are shooting with manual settings, the image will be dark if the exposure time is short or the diameter of the aperture is small (we need to adjust one of the two parameters or both to solve the problem). The image will be very bright if the time exposure is long or the diameter of the aperture is very large.
5.2.- Brightness and reflection
If the artwork is varnished or covered by glass, be aware that the flash, lights or other elements are likely to be reflected. We should either cover the lights with translucent papers and white gauzes or put the camera in another place to avoid brightness.
You can buy polarizing filters (there are some filters that are quite affordable in the market) that can remove reflections. You can use these filters if your camera is equipped with an adapter ring for them.
5.3.- Distorted image
If the image appears distorted is because we are not using the proper focal lens (try to take the picture with more or less zoom) or because the camera is not properly placed in front of the subject.
5.4.- Inadequate colors
There are two reasons why your picture may have inadequate colors:
-The picture has been taken under an incandescent light bulb: the image will appear yellowish-white. You can solve the problem by using white balance (see chapter 6).
- Lighting problems: when the photograph has different colors in all its parts. This problem happens when the subject has not received the same amount of light in all its parts. Make sure that your artwork receives light of one tonality. If you cannot remove the different lights, use the flash.
When making photographs, you have to take into account that the result is conditioned by the light falling on your subject. It is not the same shooting in sunlight, on cloudy days or indoors under an incandescent light.
If we shoot a white cardboard in sunlight, on a cloudy day or indoors, we will get pictures with different whites, (yellowish-white, bluish-white, etc,).
To compensate the different color temperatures, we can use the white balance. On most modern cameras we have an AWB (Automatic White Balance) setting. If the AWB does not work, we can set it manually.
Most of the cameras permit semi-automatic settings, which means that we can either set the white balance to automatic or set the white balance manually to take the picture in sunlight, under fluorescent or incandescent lights, etc., which will be fine for our photographs.
Advanced users can directly change color temperature, which will let them to balance color grading. They can also shoot using RAW image format, which saves data with no in-camera processing and permit using white balance settings afterwards.
A trick to correct or adjust the white balance is to place a white cardboard next to the subject which is going to be photographed, so that the cardboard is photographed as well. Thus, many editing programs will set the perfect white balance.
Once we have the photograph we have to start the digital photo processing. We are trying to shoot a real artwork to reproduce it accurately, so the photo processing will be different from the one we use in other fields.
7.1.- Focus and sharpness
Most of the photo editing programs such as Photoshop can adjust and improve the focus and sharpness of a picture. If the image we have produced is not sharp enough, we can use these programs to improve it, without abusing of them.
7.2.- Color correction and levels
Color correction and levels can distort the image fidelity. However, most of the programs have automatic settings that can be used as a demo and make your picture look closer to the original one.
7.3.- Cropping
When taking photographs, the subject is normally left with unwanted outer parts or it does not fill the picture completely. That is why we crop the photograph in order to remove the outer parts of the image and improve framing.
7.4.- Save the picture
We have to save the image in JPEG format. JPEG files suffer generational degradation when repeatedly edited and saved, so we have to save each image we produce in a new file. In this way, our pictures will not lose quality. If we repeatedly open and save the same file, it will lose quality progressively.
JPEG compression method let you choose quality. You should save the images in the highest quality.
Artelista, in collaboration with Hewlett-Pakard, makes reproductions from images starting from 2125 x 1417 pixels (which is equivalent to 3 MegaPixels).
Shutter speed: is a common term used to discuss exposure time, the effective length of time a camera's shutter is open. The slower the shutter speed, the longest de exposure time. If the exposure time is long, you will have blur images and the flash will be less effective.
Aperture: a small, circular opening inside the lens that can change in diameter to control the amount of light reaching the camera’s sensor as a picture is taken. The aperture diameter is expressed in f-stops: the lower the number the larger the aperture.
White balance: a function on the camera to compensate for different colors of light being emitted in different light sources.
Focal length: the focal length is the distance from the center of the lens to the principal foci (or focal points) of the lens. If you modify the focal lens you include more or less space (zoom) even if this space can be distorted. The 50mm focal length has been widely considered to match the field of view seen by the human eye.
CAC de Málaga hosts the largest exhibition of Vik Muniz' work ever held in Europe
through December 2
Van Gogh to Kandinsky: Symbolist Landscape in Europe 1880-1910
from July 14 to October 14.
