Color neg scanning with Vuescan, 2 different scanners

I have a Minolta Dimage Scan Multi Pro, which Iove, and have mainly used to scan chromes and black and white negatives, with Vuescan. Recently I scanned 35mm Portra negatives, well-exposed, and had a hard time getting good color. I've been using Vuescan for years, and feel I have a good grasp of color adjustments.

I scanned the same Portra negatives with Vuescan and a Canoscan 9000F, and it was much easier to get the color where I wanted it; using same Vuescan app and color controls.

Apparently the Minolta scanner has a dynamic range of 4.8; can't find that for the Canoscan, but I assume it's not higher than 4.8. The Minolta is Firewire 400; I can't get it to work with my current Mac, even with adapter, so I use an older Mac Mini for Minolta scans.

Anyone have any ideas why color adjustments in Vuescan would work much better with the Canoscan?

Anyone have any ideas why color adjustments in Vuescan would work much better with the Canoscan?

It could be just the difference between the two scanners. Your Minolta may need cleaning, that sort of thing. Vuescan doesn't update older versions any longer. To get the most out of Vuescan now, a later version operating system is required.

The Minolta is Firewire 400; I can't get it to work with my current Mac, even with adapter...

Most firewire-to-usb 'adapters' being sold are fakes that can't possibly work. Adapting Firewire/1394 to USB isn't trivial and needs both additional hardware and a translation of protocols.

The difference in colour may be due to the light-sources or filtration of the scanners being different.

My experience is that some colour negative films cause a hue rotation during scanning. Possibly due to the scanner RGB filtering not aligning with the maximum absorption of the CMY dyes in the film. That's just a guess BTW.

Whatever the cause, I sometimes have to resort to rotating the red and/or yellow channel hue(s) in PhotoShop before the colour looks right. A simple colour-balance alteration doesn't cut it.

I'd be very surprised if the Minolta's true dynamic range was anywhere near 4.8D, since the highest density of any film is well under 4.0 and most CCD scanners struggle with that. While colour negative film rarely exceeds a density range of 3 across all channels. In short, the dynamic range won't be an issue.