Totally confused by vuescan (Epson V750, MF, white balance)

[nephilim]

Hi there,

vuescan is driving me crazy at the moment :bang: I've been using this software successfully for scanning all kind of 35mm films with a Coolscan 5000. Recently, I started shooting MF and purchased an Epson V750 and this is where the trouble starts. B&W negs are no problem but colour negs are a bit problematic. This is what it needs to drive me mad:

0) latest version 8.6.66, 2 stripes of 6x6 colour negs, 3 frames each; all frames from the same series (same light, subject, etc.)
1) manual crop area, preview, selection of a blank area between two frames, preview, lock exposure, preview, lock film base colour
2) the colour tab shows rgb values for the film base 🙂
3) expand the crop area roughly to the frame size and move it over all 6 frames; the results are similar and look good 🙂
4) I'm starting to feel happy
5) under the crop tab I switch to multi crop (MF)
6) the film base rgb values in the colour tab are still there... until I
7) proceed to the second frame -> the rgb values disappear but the frame looks still good
8) frames 1-4 look consistently good but frame 5 has a strong blue/purple colour cast; frame 6 is ok again.
9) cycling back trough the frames, no 5 stays blue/purple; the base colour rgb values don't come back.

For additional fun I switch back to single crop and move the area across the frames as in 3); now even more frames get all sort of colour cast (yellow, reddish...). White balance is manual all the time and the RGB sliders haven't been touched.

I contacted the developer and he has asked me to wait until the next major beta release (coming in a few days/weeks). I'm really looking forward, as I do like the way vuescan works with my Coolscan. However, I'd love to get your input how to properly scan colour negs.

Please don't suggest Colour Perfect. I'm a Linux user and don't use photoshop or one of it's plugins. All I want is to transfer my 35mm workflow to 6x6!

Btw, I' using the betterscanning holder with ANR glass insert but I see this odd behaviour also w/o the inserts.

Any help is greatly appreciated.

Cheers,
Torsten

 

[Soothsayerman]

Yeah I get the same thing too sometimes. I set the exposure/white balance, then it changes midway during a batch scan and I have to start over from the mid point. Not sure whats going on... Im sure for me though it's something I'm not doing. Not sure what though.

 

[SonC]

The following is what I do with Photoshop after Vuescan, maybe it will help. You didn't say what you use for post processing, but you must use something.

You can scan the two strips as one scan, then duplicate it six times and fine crop each image.

I've also found that scans run faster if you scan everything as positive and then invert at the same time you are cropping. I do that both with a Coolscan and with my Microtek i900.

 

[nephilim]

Thanks for the suggestions! The problems I described above were luckily limited to one roll of film - the next roll was fine and now I'm back to 35mm stuff with the Coolscan and didn't run into trouble since. Scanning one large area is a way out. I will try this the next time or maybe when I'm relaxed enough to try that problematic roll again 😉

Thanks again!