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Supported Technologies

This narration about the new scanner would be incomplete if I didn’t tell you about the exclusive technologies that make it a really perfect machine.

Mechanics: The scanner features a mechanical resolution of 9600dpi which is two times its optical resolution. Such a high parameter is made possible by the exclusive sub-scanning technology EPSON Micro Step Drive. Its point is not only in the use of a high-precision mechanism and a special stepping motor, but also in the controller employed.

Optics: The Perfection 4990 uses EPSON ColorTrue II Imaging System technology that combines the scanner’s hardware, optical system and image-processing system for a true representation of color with less digital noise.

The number of sensitive elements in the CCD array determines the scanning resolution, but the smaller the sensitive element, the less light it receives and the weaker the useful signal is. In all scanners from EPSON each of the three basic colors is scanned with two arrays shifted by half a pixel relative to each other. This helps to improve the scan resolution without diminishing the size of the pixel or worsening the color reproduction. The name of this technology is Matrix CCD.

There’s a dedicated microlens above each
light-sensitive element of the CCD array

A dedicated microlens is placed above each photo-receiver of the CCD array to focus the light into its center. This ensures a more efficient conversion of light energy into electrical energy. This technology is called On-Chip Microlens and is employed by many manufacturers of light-sensitive arrays.

Lighter: The greatest achievement of EPSON engineers is the extended optical density range supported by the new scanner. This parameter is now 4.0Dmax against 3.8Dmax of the last-year top model. You may be wondering how they managed to achieve this. They just noticed that the masking layer of negatives let pass the blue component of the spectrum badly. The lighter’s lamp located in the scanning carriage didn’t shine through the film well enough, and the blue filters of the array didn’t get the necessary amount of light. If, as a solution, we made the carriage move slower, it would shine through the film more and would “overlight” light areas of the film. So they found another solution: to optimize the digitization of transparent originals the manufacturer first improved the Dynamic Range Control system whose earlier version had reduced the scanner’s speed characteristics much. The improvements concerned the lighter type. The blue component of the spectrum of the cold-cathode lamp was intensified and this resulted in better scans of transparent originals as well as in higher digitization speeds.

With these good speed characteristics on hands, the manufacturer decided to bring further improvements to the digitization quality. The innovations slowed the scan process somewhat and also set up harder requirements to the hardware of the computer the scanner is attached to. Here are these resource-consuming technologies:

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