One of the black magic subjects of scanning seems to be getting good colour out of your scans. Typically the profile that comes with your scanner will only produce average results with many colour errors and to get better results you need to build a custom profile. A profile is built by scanning a transparency (target) that has a range of colours on it that have been measured very accurately using professional colour spectrophotometers. These are then scanned and the resultant colours compared with the actual colours. A ‘compensation’ table is then built and embedded into an icc profile. The basic targets are called IT8s but are weak in shadow samples and also in rich color samples.
The best targets you can get are made by Hutch Color and cost £400 for a large format version. These targets have twice as many patches, a better sampling of dark colors and three times as many gray scale steps as standard IT8.7/1 and IT8.7/2 targets, which means that they can characterize cameras and scanners more accurately, especially in rich colors and dark shadows.
When we apply the profile to your scans, we convert the images to the Chromespace 100 profile (instead of ProPhoto, sRGB or AdobeRGB). This profile was created by Joseph Holmes specifically to fit the colours in modern photographic films and is a good colour space for post-processing images also as it prevents the creation of unprintable or imaginary colours.
We not only have a Hutch target for all of our scanners, we have also created a custom Hutch target for profiling colour negatives. In most cases inverting a profiled negative scan can cause colour crossovers that are difficult to eradicate but we worked with a customer of ours to create a special profile using the open source ArgyllCMS software. The software is command line only and is complex to use but it allows you to specify all of the variables in creating a profile.