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1.3 The optimum Workflow for Digital Image Processing

The idea behind processing a scanned image is primarily to reproduce the original of a picture as exactly as possible, or to improve poor originals. Individual perception plays a significant role in digital image processing. So it's important to be able to influence all the factors of a good picture manually. SilverFast 8 is the only imaging software that allows you to carry out all settings in the preview. That means that all your desired changes are always controlled in the preview and carried out in real time. The final scan is only carried out after you look at the overall corrections. So what are these criteria that make a picture look good or bad? First, there is the ratio between bright and dark, then the purity and intensity of colors and the contrast and sharpness of a picture.

The order of work steps in the digital processing of originals results from the logic and procedures of classical reproduction technology. First, brightness is checked and improved if necessary. The brightest and the darkest points – the extremes of the image – are identified and corrected using image automation.

In the first step, overly bright areas are darkened a little, while darker areas are lightened a bit. A menu selection can be used to carry out the correction for various settings, like people, landscapes, sunsets, snow or night pictures, and so on. The image automation even takes slight color casts into consideration and corrects them.

Color correction of an original is done as the second step, when colors are too pale or faded, if they should be more intensive, colder, or warmer. For these actions, two powerful tools are available: Global Color Correction (GCC), which can be used to have the image make a warmer or cooler impression, and Selective Color Correction (SCC), which can be used to change each color individually according to your specific wishes.

Especially for severe or multicolored color casts, there is a special tool available, the Neutral Pipette (MidPiP), which can remove up to 4 color casts. It's a truly magical tool, for example for slides which seem impossible to process.

The next step, the checking and possible increase of contrast, should always be done before adjusting sharpness, because any gray haze can be resolved first for better sharpness adjustment. This setting is adjusted in real time using a control. Once everything is corrected to your taste, then you can continue with sharpness adjustment.

The evaluation of whether an image can be called "sharp" is also a matter of subjective, individual perception. The difference in brightness and darkness between adjacent areas or objects (detail contrast) determines the optical perception of sharpness. With SilverFast, it's possible to use a 1:1 image displayed in the zoom window to make very detailed adjustments to sharpness using a control. The term "Unsharp Masking" (USM) comes from the analog photo laboratory world, where a slightly blurry positive copy was originally made manually. Superimposed on the original negative, this process makes a stronger contrast at the edges.

As image processing continues, after sharpening the next step is to pay particular attention to the area of more severe image distortions. This includes scratch removal with the SRD/iSRC tool ((infrared) Smart Removal of Defects) or using GANE (Grain and Noise Elimination) to reduce grain, which – depending on the type of film – can often degrade an image.


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