Copyright Michael Karbo, Denmark, Europe.
Chapter 8. Cropping reduces the pixels
When we take photographs digitally, we have the advantage of the fact that the image can be cropped before it is printed. Cropping improves most photographs as they are usually taken with undesirable areas in them. But cropping also removes pixels from the image so the resolution has to be suitable high if the image quality is to be retained.
Analog images can’t usually be cropped. The film was taken to a photo shop, where only copies of the full pictures were developed. Now that photographs are taken digitally, images can be easily edited. It is easy to remove excessive image areas. Some cameras allow you, in fact, to crop images directly in the camera with the help of the menu system. But normally cropping is done in a computer.
The intention of cropping is to achieve a better composition in the image – an improved balance – by removing superfluous image areas.
Figur 28. An image’s composition is improved by cropping. It is done here with the crop tool in the Photoshop Elements program.
The finished picture has a very different format from the original photograph. This image is relatively tall and narrow, but this isn’t important. If the image is printed onto paper in a standard measurement, the sheet can be easily cropped to that it fits the photograph.
It costs pixels every time you crop, which is why every photograph ought to have a high resolution right from the start! You can see the result of heavy cropping in this image (Figur 29) of a French market place. Less than a quarter of the original pixels are used in this section. This sort of heavy cropping can only be done because there are lots of pixels and thereby many image details available in the original material.
It is often necessary to crop photographs – which is why it is a good idea to have at least 5 or 6 MP available in original photographs. This also applies if you are going to process a photograph in an image program. You can very quickly lose image data here so it is a good thing if you have masses of pixels to start with. But, however, as mentioned earlier, 3 or 4 MP might be enough – if you don’t expect to have to crop your images or process them in a computer.
Figur 29. If there are lots of pixels available, then you can crop an image heavily. Only 23% of the original amount of pixels is left in the section to the right. But because the resolution was high, there are enough image details to ensure a fine print in a well-sized format.