Many of Microfacs’ services revolve around digitizing. Digitizing is taking a physical medium such as a document or microfilm and converting that into a digital format that can be displayed, stored and edited on a computer.
The digitizing process starts with scanning. Scanning is pretty common, in fact many businesses and home users might have a desktop or flatbed scanner. The scanner equipment that is used in commercially converting high volumes of documents or microfilm is much more sophisticated than a desktop scanner, but the principle is the same.
How does a desktop scanner work?
A document is laid flat against a glass plate. A strong UV light source is underneath the glass; the light beams reflect off the document and bounce off a reflector that focuses the light beams to a photo sensitive device that converts light rays or photons into electrical signals. The reflected light has varying degrees of intensity depending on the density of the image on the document that the light reflected from. A highly dense, dark spot will reflect very little light. A white area will reflect a higher intensity of light. So the reflected light intensity as it hits the photo sensors is proportional to the darkness of the image from which the light reflected. The electronic pulses generated by the photos sensitive device are proportional to the intensity of the light beam.
The electric signals are then converted to computer code, which can be manipulated by software to correct, enhance, resize and convert to an image format. The most common formats are Tiff, Jpeg, PNG and PDF. The quality of image depends on: The consistency of light source, the cleanliness and clarity of the reflectors, the quality of the photo sensors and the capability of the CPU. Most desktop scanners are built with relatively inexpensive components. The resulting resolution, quality and speed of scanning will vary on the quality of these components. So the overall quality and speed of a simple desktop scanner will be far inferior to a scanner used by digitizing professionals.
How does scanning film work?
The basic principles of scanning film versus a document are similar in that light beams of various intensities are converted to electrical signals of corresponding strength which then getconverted to computer code. The main difference is that because microfilm is translucent, with varying grayscale density that defines the image, the photo sensitive device collects light that passes through the film rather than a reflected light. The grayscale patterns vary from a total opaque black to totally translucent clear with shades or tones of grey in between. The light is filtered as it passes through the substrate. A very black area will result in very low intensity light and lighter shades of grey will have higher intensities of light. The light beam is converted to an electronic signal where the strength of the signal is proportional to the intensity of filtered light.
The other differences in scanning equipment revolve around the type of medium being scanned. Microfilm comes in reels so the material has to be feed and collected on reels and stepped and repeated through the scanner. Microfiche is in sheets so a sheet handling system is used where the sheet is feed in to the scanner and stepped through each image. Aperture cards require a card handling system. The handling system combined with the quality of components and size and power of the computer determine the quality, resolution and speed that film is digitized.
Some of the more sophisticated scanners will do a number of quality control functions such as auto image alignment, image corrections, scaling and compression. As with the document scanner, film scanners will convert the images to a variety of formats.
Microfacs uses some of the best equipment on the market so that digital conversion can be performed at the highest quality and lowest cost.