Save Multiexposure scans as separate images

[alphalam]

I'm a Silverfast Ai Studio 8 user with a Plustek 120 scanner.

My question here is how can I obtain the multiexposure scans as a separate file? When I select 64bits HDRi mode with multiexposure the image is a combination of the normal scan and the longer exposure scan. What I would like is a separate file or image for the longer exposure scan.

Why do I need this? I'm trying to use SilverFast to scan negatives and then use a separate software to correct the negatives. The problem I run into a very limited bit-depth for the Blue channel, even with HDR/HDRi scans.

Most negatives have different densities responsible for R, B and G channels. For example the Portra 160 negative I scanned has mean density of 0.8, 1.1 and 1.45 for R, G and B channels respectively. When scanned using the HDR mode in SilverFast the mean values of R, G and B are 10386, 5205 and 2325 respectively. This example shows that the B channel is using a very limited range of values (700 - 3500).

When I enabled multi-exposure this range did not change significantly. This means that with or without multi-exposure the Blue channel always suffered from a limited bit-depth (around 11.5 bits). This is because the output is a single image combined with 3 channels and these 3 channels are adjusted for the same exposure.

I do not think this output format takes full advantage of the multi-exposure feature. It would be better if the longer exposure scan is saved in a separate file. The question is how can I do this?

[LSI_Ketelhohn]

Dear customer,

It is unfortunately not possible to save the MultiExposure scan into a separate file.

kind regards,
Arne Ketelhohn.