They could be hand-drawn logos required for document letterheads. They could even be pages of text which suitable software could read and save as an editable text file. However, flatbed scanners are the most versatile and popular format. These are capable of capturing colour pictures, documents, pages from books and magazines, and, with the right attachments, even scan transparent photographic film. In other word, scanners convert analogue data into digital data.
All scanners work on the same principle of reflectance or transmission.
When desktop scanners were first introduced, many manufacturers used fluorescent bulbs as light sources. For these reasons, most manufacturers have moved to 'cold-cathode' bulbs . These differ from standard fluorescent bulbs in that they have no filament. They therefore operate at much lower temperatures and, as a consequence, are more reliable. Standard f luorescent bulbs are now found primarily on low-cost units and older models.