Russ,
Sorry, I’m late to the party in the discussion. I agree with Michael, that you have gotten about all you can out of the slide of 498. It’s a backlit Kodachrome image, and those can be very tough to handle. Comparing what you see in projecting a slide and then scanning and printing the same slide will often leave you disappointed. The projection is transmitted light, while the print is reflected light. The color saturation, shadow detail, etc could never be the same. Our monitors are somewhere in between, and unless you have a fairly recent one such as the high end NEC’s, you are likely not seeing some of the Adobe color space that exists in the scanned file.
HDR is a good way of handling images like the one of 498, but the technique really shines when you have a series of camera exposures taken at different values. Sadly, not possible with the 498 photo unless that illusive time machine shows up. I’ve tried the single image/multiple scan technique with a few of my difficult images. Frankly, careful scanning using correctly set white and black points then using the shadow and highlight recovery tools in Photoshop and Elements produced about as good a result. What you did by scanning the sky separately is the best way to handle that image. You just need a little practice in combining the two layers and disguising the border.
The adjustments in the photo editing programs are quite powerful, and many folks overdo them. Subtlety is the key. I see photos every day that have been shadow/highlighted to death. It looks un-natural, almost abstract. Lots of folks like very saturated color, and the saturation tool is often way overused as well.
Noise in the shadows is sort of the equivalent of grain. In either digital or film it’s the result of underexposure. As you see with the 498 image, if you bring the shadows up too far, noise pops up. You can eliminate the noise with one of the noise reduction programs, but at the cost of some of the fine detail in the image. It’s a delicate dance with artistic decisions made along the way. My personal preference is for a “natural” look. I try to steer away from colors that don’t exist in nature.
In your PM you asked about an ICC file for Kodachrome. I’ve never seen one. Most of the scans I’ve done for quite a while have been using Nikonscan. There is a very good Kodachrome setting in the program, but no reference to an ICC profile.
I checked my C/Windows/System32/Spool/Drivers/Color file in Win 7 and there is nothing pointing to a Kodachrome profile. It appears Vuescan has a similar setup with a Kodachrome setting. It might be worth contacting Ed Hamrick to see if he actually has a color profile for Kodachrome that he uses in Vuescan.