Scanned images from negatives don't match prints - colour casts and dull colours

[davemmm]

Hi there,<br>

I'm using a Minolta DiMAGE Scan Elite 5400 to scan Fuji superia colour negatives.

Some of the scans turn out fine, but on some there's an unpredictable colour

cast Often it's magenta - like this bench:<br>

<img

src="http://beoko.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=811&g2_serialNumber=22">

<p>

The cast is inconsistent, and can vary from frame to frame on the same roll:<br>

<img

src="http://beoko.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=574&g2_serialNumber=2">

<br>

<img

src="http://beoko.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=577&g2_serialNumber=22">

<p>

Same flower, same roll of film, same camera, same scanning settings, but a big

difference in colour.<br>

I've not told the scanner software to make corrections, just do auto-exposure. I

did think it was a monitor calibration issue, but when I saw the flowers I

decided it probably wasn't.<br>

<p>

I'm using a Custom Wizard on the Minolta software to scan the film in strips of

4 and assign serial numbers to each frame, and adjust exposure & focus

automatically. Should I be doing image correction at the scanning stage?<p>

Any help is greatly appreciated. For more examples, take a look at the <a

href="http://beoko.com/gallery/main.php?g2_itemId=191">carnival pictures in my

gallery</a> - they don't have the same 'pop' as the machine prints I got from

the developers :(<p>

 

David<p>

<a href="http://photo.beoko.com">photo.beoko.com</a>

[steven_clark]

I'd guess the scanner still does basic automatic correction in the autoexposure process. Try building a manual exposure and see what happens. Consistency is one of the things Vuescan is good at if you're ever looking for an alternative solution.

[jonathan_ratzlaff]

Quite simple. You have to take into consideration what light the image was taken in when the picture was taken. The scanner does corrections, based on what it thinks is the proper exposure, however the image in the first scan was taken in warm light which creates a reddish colour cast resultin in magenta in the shadow on the bench. Don't use auto esposure and adjustments.<div></div>

[roger_smith4]

You shouldn't need to vary exposures for color negatives- one setting should do for all. This will help with consistency.

 

" they don't have the same 'pop' as the machine prints I got from the developers :("

 

Alas, post-processing is pretty much required for decent scanning results. With a little practice you'll blow away what the labs were giving you and have total control.

[mendel_leisk]

Auto-Exposure is likely the culprit for the varying cast. Minolta Scan Utility is adjusting the red, green and blue exposure, frame by frame. I can't really give you a good alternative, I've not got very far with color neg myself. Something you could try:

 

1. Tell MSU you're scanning slides.

 

2. Preview a frame with just leader, with auto-exposure off.

 

3. In the Exposure tab, adjust the master, red, green, & blue sliders to bring the preview r/g/b values as close as possible to 255/255/255. This can be assessed by moving the mouse around the preview and observing the readings. If they very occasionally hit 255, that is ok. This is the very brightest you'll ever see from your film. BTW, it *should* look very close to bright, neutral white. Now, scan the rest of the roll with these exposure settings locked.

 

4. Then, either:

 

a: Output 16 bit, invert and experiment with levels/curves in Photoshop.

 

b: Output 16 bit linear, and experiment with Vuescan Scan-From-Disk.

 

I've really *not* got too far with color negs, and was not happy with my results. But these are some things I've tried.

 

As to the extra 'pop' of commercial prints: try clipping both ends by 5~7%. I believe that's about what they do.

[bruce_rubenstein]

Were the pictures originally taken in an auto exposure mode or manual? (was the same exposure used for both flower shots?) When you send negative film for processing and prints you never see the small differences in exposure, but the scanner will, and give different frame to frame scans if the exposure or lighting are different.