Weird preview with Vuescan - please help

[konicaman]

When I am scanning BW negatives with Vuescan using a plustek 7600i, I get these weird preview images with magenta hue and something that looks like a solarizing effect. The final scan does not have these problems, but setting the exposure on a preview image like that is almost impossible. I scan the image as 24-bit color and can accept a slight colorcast, but this is really weird. Any ideas?

[mdruziak]

Hi Mark from Plustek here. Does this issue repeat if you use Silverfast?

[EdwardKaraa]

You must be scanning in color. The film is greenish hence the magenta cast.

[krötenblender]

I think, I have a similar effect, when scanning BW in setting color negative. Please try to use BW negative as a setting with 16 bit gray values. That is, what I use with a reflecta CrystalScan 7200 and it works fine.

[cabbiinc]

Make sure everything on the Filter tab is turned off.

[CNNY]

In Vuescan there is an option to specify which color channel to use while scanning grayscale. This way you can get any advantage there is from scanning in color, while keeping your file size down. A 16 bit gray file is still smaller than an 8bit RGB file.
I would do some test scans with your negatives scanning with each color channel to find the one that looks best with your images. The differences are subtle, but you will notice some variation in the look of the grain. I personally tend to use the green channel.

[konicaman]

Nope, it does not happen in Silverfast no matter if I scan in color or BW.

Turning off everything in the Filter tab reduces the amount of times that this happens, but it is rather inconsistent.

Now, I can see a certain logic in the greenish hue from the film, and as mentioned a certain color cast is fully acceptable, but the solarizing effect puzzles me.

@Krötenblender - my old version of Photoshop sometimes flips completely when presented with a 16-bit greyscale file, but setting to 24-bit color and BW negative seems to solve the problem. Just not used to this from Epson and Silverfast software.

Thanks for your help!

[konicaman]

@CNNY - interesting will give it a go!

[Lawrence A.]

I don't have your scanner, but if I inadvertently preview a BW neg in color on my my Coolscan 9000, I just get a slightly reddish-brown cast. Best bet is to scan in 16 bit gray scale and convert to RGB if you want to use Photoshop channel mixers in monotone to adjusted the scale.

I don't like vuescan generally but have to use it with my Epson 4990