The processing steps are done for both the preview scan and the full scan.
The first step is using the infrared data to do a first attempt at dust removal (if enabled). This reads the whole image from the memory buffer to characterize the relationship between the color channels and the infrared channel. Then it reads each line once, correcting it for dust spots and passing each line to the subsequent steps for further processing.
The next step is applying the cleaning filter. This filter tries to remove dust spots by using the infrared data to identify and remove dust spots and filling in these spots with image data just outside the dust spots. This filter also reduces the appearance of film grain using a sigma filter.
If saving files, the "Files|Save raw file" option is enabled and "Files|Raw save with" is set to "Save", the data at this stage is written to a tiff file. This raw data can subsequently be re-processed by setting the "Device|Scan from" option to "Disk".
Next, the restore colors and restore fading filters are applied (if enabled). This reads the whole image once to detect the original colors of the image and then reads each line once to correct for color shifts and dye fading.
The next step is performing corrections for film media. This reads the whole image once to compute the intensity of the film base, and then reads each line, corrects it based on film characteristics, and passes each line to the subsequent steps for further processing.
At this point sharpening is performed. A simple 3x3 filter is used to increase the sharpness of the image.
The last step is color correction. The whole image is read once, and the options from the Color tab are used to convert to the final colors of the saved images. The inputs to this step are 16-bit linear light samples, and the outputs from this step are gamma corrected samples.
Once the image data has been corrected, the preview image data is displayed in the Preview tab or the scan image data is optionally displayed in the Scan tab or written to a .tif file, a .jpg file, or an index file.
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