Why is the colour coming out wrong when I scan?

Scanning a document to capture an exact colour copy of the original can be difficult. The main reason for colour problems when scanning is due to colour space. Colour space affects the colours of the scanned document and how it will look on the screen and when printed. It’s important to understand that the colour space you use when scanning your document will define how colours appear, whether it be on your computer monitor, printouts, etc.

Colour space is simply the range of colours that a device (scanner) or program (image editing software) can display or print. For example, most computers are capable of displaying 17 million colours (RGB), while scanners are normally limited to just 256 distinct colours (CMYK). So if the document you are scanning has more than 256 distinct colours, the scanner will not be able to capture them all accurately.

In addition to colour space, another reason why scanned colours may be off is because of the type of scanning technology being used. Different types of scanning technologies use different lights to capture the colours of a document. For example, CCD (charge-coupled device) scanners use red, green, and blue light to capture colours, but can struggle to capture pale yellow, pink and orange hues; however, LED (light-emitting diode) scanners use several different wavelengths of light to capture a wider range of colours.

Other possible causes for colour issues when scanning documents include choosing the wrong colour mode setting, a faulty scanner, incorrect profiles, and improper image resolution settings.

In order to correct colour issues when scanning documents, make sure you are using the correct colour mode, such as RGB or CMYK, and that the scanner is in working condition. If you are using a profile, make sure it is set correctly and that you have the right printer and/or scanner profile installed. Finally, if you are scanning a large image, be sure to set the image resolution to at least 300 dpi (dots per inch) to ensure the colour is captured accurately.