If I understand your question correctly you place 4 slides in a transparency adapter, enable
Multi Crop and then Vuescan recognizes (erroneously) that you want to scan 8 slides.
Subsequently it starts scanning all 8 regions where it thinks slides are present.
To only scan the four slides follow these steps:
Batch Scan in the
All in the
Batch Scan options drop-down menu.
- Do a preview scan.
- After that choose
List instead of
All in the
Batch Scan options.
- Now you have to find out what frame numbers the actual slides have. You can find this by varying the
Frame number in the
Input tab and noting the frame numbers that actually select a slide. Let's assume Vuescan recognized your 4 slides under frame #1, #4, #5 and #8.
- Now in the text box next to the
Batch List option write down
1,4,5,8. This directs Vuescan to only scan these frames.
You can find more information on the commands in the Vuescan manual, especially on page 57 where the
Batch List option is explained.
As my scanner is not supported on my OS anymore I don't have Vuescan installed to show screenshots, but these steps + the manual should be enough.