iSRD

Conventional software based dust and scratch removal tools
Slides and negatives do always have small dust particles and tiny scratches on them, even when handled very carefully. There are several software based techniques to remove this defects during the scan process by considering the surrounding image information. However, it is hardly possible for these tools to differentiate between actual scratches and image details to be preserved. Thus, often not all defects will get removed, many details will get lost too, or a very time-consuming manual retouch is necessary. LaserSoft Imaging has developed a solution for this problem:

SilverFast's hardware based dust and scratch removal tool with infrared technology (iSRD)
Contrary to coventional techniques the SilverFast dust and scratch removal functionality iSRD is based on hardware. It is using the scanner's infrared channel for defect detection. Infrared light has a very wide wave-length, which allows to pass through film emulsion of negatives and slides without resistance, in contrast, scratches and dust particles are reflecting it. iSRD utilizes this behavior as follows. The image is getting scanned two times, where one scan is the regular RGB scan and the second is the additional infrared scan, that captures defects like dust and scratches only. Thereafter the calculative dust and scratch removal takes effect just there, where the infrared channel has detected any defects. Important details won't get lost this way.


Example images: Before and after iSRD dust and scratch removal.
(Click the images to enlarge them, please.)

Further advantages of SilverFast iSRD over other systems
Some manufacturers have developed their own systems to remove dust and scratches like FARE or Digital ICE. SilverFast iSRD differs in many cases by more sophisticated functions and additional features:

• iSRD supports up-to-date multi-core processors.
  Thus, iSRD is running especially fast on such systems using the technique of multi-threading.

• Automatic Mode: iSRD is working on it's own, without having the user to do any adjustements. The removal is effecting the complete active scanning frame.
• Manual Mode:For challenging corrections and optimum results the user is able to configure iSRD himself optionally. In detail:
• Any corrections and adjustements are shown in a preview windows.
• The sensibility of defect detection is controllable.
• The area around defects getting used for corrections is adjustable.
• Layers and masks can be used to apply varying corrections on different parts of the image.
• iSRD and SRD are usable in parallel for an optimum of defect removal.
• By utilization of iSRD & SRD and several layers & masks it is even possible to remove dust and scratches from very challenging film material like Kodachrome or B/W-film reliably. This isn't achievable with similar systems from other manufacturers.

Example image: Before and after applying the SilverFast Kodachrome workflow including iSRD dust and scratch removal. (Click the image to enlarge, please.)

Note: SilverFast iSRD can not support any scanner, which is not equipped with infrared technology.
The SilverFast SE versions do only contain the automatic mode.