Theme: Frame card
Q:

Scan type
I have a Nikon LS-1000 and a LS-2000 model. With SilverFast on LS-2000 I have as Scan type the option to scan 48bit data. This option is missing in SilverFast for my LS-1000, why?

A:

The reason why it is possible to output 48bit data with the LS-2000 but not with the LS-1000 is that the ability to output "real 36bit data" as 48bit data is only implemented in the newer Nikon LS2000. Both scanners (LS-2000 and LS-1000) only work with 36bit data, where the LS-1000 can convert its output data from internal 36bit to 24bit external data (which is what the scan software forwards to the image processing application). The LS-2000, however, can "blow up" its internal 36bit data to 48bit output data, where "neutral values" (zeros) are added to the true 12bit data per channel, in order to obtain a bit depth of 16bit per channel (no additional information than the internal "working data" is transfered!).

The LS-1000 model lacks the ability to output it's internal 36bit data depth.


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Q:

Scan type
What are the optimum settings for line-art scans?

A:

when the preview is there, select as Scan type = "1bit line Art" in the SilverFast Frame-card > Scan type.

now you minimize the scan frame - in the pre scan window - so that it covers just 3 or 4 lines of the text of your original and click the zoom button in SilverFast Ai window. SilverFast will generate a zoomed preview.

Next step is to call the "gradation dialog" in order to adjust the brightness. In the SilverFast Ai window three buttons left of the zoom-button, the brightness controll will be the only live slider.
You adjust the brightness so that in the zoom-preview the characters of the text are clearly seen - they should not merge with neighboring characters nor should they fade.

When the brightness is correctly set, click the zoom-button again to return to the normal pre scan and now enlarge the scan frame again to cover all the text you want to scan. Set the scan resolution to approx 600dpi.

Start the scan.


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Q:

What is the Q-Factor in SilverFast?

A:

In SilverFast you have the possiblility to determine the scan resolution by setting the Quality Factor (Q-Factor). This Q-Factor indicates the relation line screen resolution --> scan reslolution. A Q-Factor of 1.5 means that the scan resolution is 1.5 times larger than the line screen resolution.

Calculating the maximum scan resolution with no information loss. desired resolution x max. optical resolution = max. scaling factor


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Q:

SilverFast changes the value for the scaling factor (normally 100%) on its own when I increase my scan resolution beyond a certain value. Is this a bug?

A:

scanning printed media with the "USM&descreening" filter applied will limit the maximum scaling factor to double the screening value of lines per inch. This means, when setting the scan resolution to a high value, thus changing the calculated value for lines per inch (lpi) to twice the screening value in the "USM&descreening" filter, SilverFast will automatically downscale the scan frame (output size). This limit was implemented to avoid artefacts if the descreening value exeeds twice the original screening value.


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Q:

What is the difference between the Filter options "Descreening" and "USM & Descreening"

A:

Descreening is the function to calculate print patterns (moiré) out of scans made from printed media.
As the descreening calculations goes along with a little loss in sharpness, LSI combined the functions "Unsharp masking" and "descreening" into one option.

USM&Descreening allows to increase the tonal values of pixels in "border areas" of a given image. In areas where darker pixels and bright pixels are next to each other the intensity of ONLY these pixel values can be increased (by moving a slider in the USM&Descreening dialog)
The effect is that the resulting scan appears sharper to the human eye - and the morié pattern is also suppressed


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Q:

When am I supposed to use the GANE function?

A:

the GANE functions applies where film material is scanned. This tool is a smoothing tool which helps to suppress film corn, which may become visible when scanning very sensitive film material (films with high ASA values).

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