VueScan does automatic cropping and automatic white balance, and then lets you use an external image viewer to tweak the cropping (if you desire) and tweak the color balance (if necessary). A lot of effort has been put into VueScan to make it accurately crop and white-balance scans, so the amount of manual adjustment needed is minimal - something you'll appreciate when batch scanning large numbers of slides or negatives. You can also manually crop images by using the left mouse button to select the crop area in the image preview window.
VueScan's user interface has a large number of options, but the only thing you normally need to do is set the frame number(s) to scan (in the lower left corner) and then choose the "Scan|Device" command. If you've changed a lot of options and things aren't working right, just reset all the options to their default values with the "File|Default options" command.
There are two types of scans - a preview and a scan. The main difference between the preview and the scan is that no files are written when doing a preview. If you need to experiment with various options before writing the files, you can change options and see the effects of these changes by re-doing the preview with the "Preview|Memory" command.
A scan involves reading the raw scan data (from one of 3 sources), processing the raw scan data to get accurate colors, and writing the processed image data (to up to 4 destinations).
The raw scan data can come from one of:
The settings that affect both the preview and the scan are primarily in the left-hand tabs, and the settings that affect the scan are in the right-hand tabs.
The processed image data can go to any combination of:
Note that there is only one memory buffer for the most recent preview, and only one memory buffer for the most recent scan. The usefulness of the memory buffer is that you can change options that affect the processed image and re-do the processing without needing to re-scan the film. Film is delicate, so you want to minimize how long it's in the scanner and how many times it's handled.
One of the most powerful features of VueScan is that you can save the raw scan data in a file (using "Files|Output raw file") when scanning from a film scanner. These raw scan files can then be reprocessed later (or with later, improved versions of VueScan) without needing to re-scan the actual film. You shouldn't ever need to scan the same piece of film twice.
You only need to save raw scan files if you foresee a need to reprocess the film in a later session. In any case, VueScan always keeps the raw data from the most recent scan in memory, so you can always reprocess it without needing to rescan the film. The only time you'll need to rescan the film is if you want to scan at a higher resolution, or if you want to manually change the exposure or focus.
The only preview window is primarily used to show the cropping that the automatic cropping is selected, and to let you change this cropping if necessary. It's also used to give you a rough idea of what the color and intensity will look like in the final scan.
VueScan uses color correction tables which have been derived from a Kodak Q60 calibration slide and which produce colors accurate to better than 1%. The default color primaries and white point are the same as used by the Kodak PhotoCD system - Rec. 709 primaries with a D65 white point. (There is also an option to choose different color spaces.)
Note that the images produced by VueScan from scanned negatives may vary in intensity and contrast from the prints you get back from a photofinisher. If you look closely at the prints, you'll probably see that the detail in the highlights of the image have been lost, and the detail in the dark parts of images can't be seen. VueScan tries to preserve the detail in the dark and light parts of images, and you can control how much detail in the dark and light parts is preserved by experimenting with the "Color|Image contrast" and "Color|Image intensity" options.
You can use VueScan for batch scanning with the HP PhotoSmart, Minolta, Polaroid SprintScan 4000, Microtek ArtixScan 4000 and Nikon scanners. VueScan has been designed to scan as fast as possible, and to do post-processing of the images while the film ejects and while you prepare the next slide or negative to be scanned. This way you can do batch processing as fast as is practical.