Multi-Exposure is a patend-registered (Karl-Heinz Zahorsky, EP: 1744278, US 8,693,808) exposure blending technique developed by LaserSoft Imaging for scanning transparent originals like slides, negatives, and film strips with increased dynamic range.
Due to the usage of multiple layers with different photosensitivities an ordinary slide film reaches a dynamic range of 8 aperture stops, where an optimum exposed and developed negativ can even reach up to 12 stops. Many scanners can't capture this dynamic range, so that a coventional scanning would result in a loss of image details.
With the Multi-Exposure technology the originals get scanned multiple times, but with different exposure times. By taking these several single scans into account the software calculates the final HDR-Scan. Multi-Exposure increases the dynamic range considerably, saving details especially in the light and shadow areas of an image. Multi-Exposure is not working with reflective originals, transmissive only. It has to be distinguished from Multi-Sampling, which is also scanning multiple times, but with unaltered exposure. The Multi-Sampling technique reduces noise patterns but does not increase the dynamic range.
The European Digital Press Association (EDP) awarded LaserSoft Imaging's SilverFast as the 'Best colour management software of the year 2008' generally for improving the dynamic range of most scanners with Multi-Exposure.