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Frame size - very different autoexposure results

PostPosted: Thu Apr 07, 2011 10:27 pm
by Misty
I'm having some difficulty with the frame sizes in NegaFix, and hoped other users/staff could help out.

The autoexposure used by NegaFix appears to change substantially based on only very small changes in the frame size. The examples I've posted below show this - with almost no visible difference in frame size, the result is very different. This doesn't just affect brightness, but can also mean the difference between accurate colour reproduction and very strange colours.

Related to this, I also had a question regarding framing. The SilverFast manual advises users to place the guidelines within the film frame. However, my preference is to scan as much of the image as possible, which means scanning outside the edges of the frame. Can anyone advise on settings to assist in obtaining good results when scanning negatives this way?

Re: Frame size - very different autoexposure results

PostPosted: Fri Apr 08, 2011 4:51 pm
by LSI_Morales
Dear Misty

Misty wrote:The autoexposure used by NegaFix appears to change substantially based on only very small changes in the frame size. The examples I've posted below show this - with almost no visible difference in frame size, the result is very different. This doesn't just affect brightness, but can also mean the difference between accurate colour reproduction and very strange colours.


It is correct, hence the importance of framing your negatives correctly.

Misty wrote:The SilverFast manual advises users to place the guidelines within the film frame. However, my preference is to scan as much of the image as possible, which means scanning outside the edges of the frame. Can anyone advise on settings to assist in obtaining good results when scanning negatives this way?


Actually when you take the picture the viewfinder of the camera already crops between 5 to 10 % of the field of view, hence your negative already contains more details than those you have framed during the shooting.
Cropping a bit out should not be much of a problem. However if you insist on precision then you should make the frame first a bit smaller to get the accurate correction, then deactivating CCR and then resizing the scanning frame. You could also use that technique to get even the sprockets of the filmstrip or to make contact sheets in a flatbed scanner.

Cheers

Re: Frame size - very different autoexposure results

PostPosted: Fri Apr 08, 2011 5:01 pm
by Misty
Dear Alejandro,

Thank you for your reply.

While I'm aware that the film has more than was seen in the viewfinder, the photos I'm scanning are archival photos for which I am not the photographer - any cropping is not acceptable in this context.

I tried your "CCR" advice, but it does not seem to be working for me. Whether or not CCR is disabled in the NegaFix dialogue box, resizing the scanning frame still results in changes to the exposure.

Re: Frame size - very different autoexposure results

PostPosted: Mon Apr 11, 2011 7:49 am
by LSI_Morales
Dear Misty,

Some time ago i wrote an article on our Blog dealing with some issues while scanning black and white, perhaps this might help you.
http://blog.silverfast.com/quicktip-using-negafix-on-heavily-scratched-negatives/#more-331

Cheers

Re: Frame size - very different autoexposure results

PostPosted: Mon Apr 11, 2011 5:32 pm
by Misty
Thank you, Alejandro. That was quite helpful.

Re: Frame size - very different autoexposure results

PostPosted: Tue Apr 12, 2011 7:34 am
by LSI_Morales
Sweet!