Mark -- I appreciate the time you have put into responding to me.
I suspect what I am looking at here may be a bit challenging. I followed your workflow and setting suggestions and got about the same result. Things changed a little. (Incidentally, I clicked on service dialog when opening SF which purported to return everything to defaults before trying out your suggestions).
In the process of doing this, I tried scanning some photographs and noticed that the hue shifts I am seeing with are not nearly as noticeable in a photo as they are when photographing paintings. In paintings there are often large blocks of color, so hue shifts are very noticeable. Two of the shifts I am getting are from a pinkish rose toward a more pure red pink and from a turquoise blue towards a more pure blue. I notice that by correcting the pink towards a green in an RGB context, the hue shifts more towards the original (in terms of the red hue shift) These are just two of the shifts I am seeing that are most noticeable. In a photo these shifts seem to be much less noticeable and, perhaps, not as important if one is looking for something that works, is effective and looks good. When reproducing art, the artist is going to be looking primarily at whether it is true to the original piece.
Am I trying to do something that is not possible? Can a properly generated profile produce color output files true to the original? If I invest in one of these pieces of scan software, will I be able to produce a profile that works (neither offers any money back if it doesn't work nor provides a demo that allows for demoing profile creation)?
I came to this assuming that it was possible to preserve accurate colors with a scanner and am rather confused as to why I am having so much trouble.
Scanning artwork is more challenging than scanning most photos because the demands on colour accuracy are challenging in the sense that you have the original to compare side by side, and as you say, artists are sensitive to the accuracy of the reproduction of their artwork. The same can be said for product advertising photography compared with landscape photography. Neither from a digital camera, nor from a scanner, will you get totally accurate colour at the push of a button. Both require some
post-capture editing. The purpose of the profiling is to bring the result as close as the technology allows, and therefore minimize the number and extent of these adjustments.
Franks' point about making sure CCR is set to 0 is worth verifying. However, by making a scan in 48-bit HDR mode, all such adjustments are turned-off, and it produces a linear unadjusted scan, except that by checking the Gamma 2.2 box in Preferences>General, you are instructing SilverFast to include a Gamma adjustment for purposes of seeing a result in Photoshop that has more contrast and luminance than you would get from the Gamma 1.0 result that an HDR scan otherwise provides.
Your point about the irreversibility of a purchase including profiling targets and profiling capability is correct. Hence it is a bit of a risk. For scanning artwork on the flatbed the correct target you need is the reflective target, and for slides there are options to get a Kodachrome target (quite expensive because supply is dwindling and not replaceable) or a non-Kodachrome target. Unfortunately, it's not possible to predict what amount of incremental improvement you would observe from custom profiling, because we don't know the extent of difference between the colour and luminance rendering of your scanner compared with the one LSI used to make their canned profiles.