Problems with colors in preview of silverfast

[Bubba]

I've recently purchased an epson prefection 4870 with SiverFast SE6.
Scanning most negatives works perfectly well, but when it comes to monochrom images the preview shows really funny colors. With monochrom I mean photos that consist mainly of one color, like photos of water or sky - so, green water turns for example into magenta in the preview. When I drag one side of the selection frame out of the image into the black the preview suddenly shows roughly the right color.
Recently I tried to scan a photo of a field of yellow flowers with a few bits of green in it. When I've got the selection frame on a differnt negative the preview of the flower field shows the right colors but as soon as I drag the frame onto the flower field negative the colors change. this time yellow stays yellow but the green turns into blue. Isn't that crazy.
Would be great to get some advice from you guys.
Thanx

[LSI_Noack]

Dear Bubba

sometimes the version of SilverFast distributed with a bundle is not a relatively recent one.
Please try updating to the latest release of SilverFast SE for your Epson scanner first.

You can download the latest release from our website for free:
https://www.silverfast.com/sf-download/b ... roduct=414
This shall resolve your problem.

If the problem persists, however, please don't hesitate to contact LaserSoft Imaging support staff: https://www.silverfast.com/problemreport/en.html
I would appreciate if you could paste a fresh copy of the SF_Logfile in the problem report.
Thanks in advance for your co-operation.

[Gregory C]

(I might be really wrong here. I hope the support guys can chime in.)

I would suggest that your problem is related specifically to the fact that the images consist of mainly one colour. I had the same problem with photos taken underwater.

the Negafix function (correct me if I'm wrong guys) tries to balance the three colour channels even if it's the inappropriate thing to do. there's no way for the system to know that the image contains very little of everything except the main colour so it tries to balance everything. the result is hugely distorted colour.

you might need to create a custom Negafix profile for your images and turn off auto-fix. just turning off auto-fix might solve your problems enough to allow you to continue working with the images.

I don't have SF Ai on my iBook so I cannot remember exactly the name of the control to toggle. however, I remember that it's in the Negafix Expert panel. open the Expert panel (by clicking the Professor icon) and uncheck the Auto button next to the slider. that should do it?

the support guys here can probably tell you more.

once you have a working Negafix profile, everything else should be relatively easy. automatic colour adjustment/correction of negatives is extremely complex. images consisting of basically one colour are almost impossible to correct automatically.

the reason the image looks ok when you move the scanning area to an principally made up of black is that the black region contains relatively equal amounts of all colour channels.

regards
Gregory