Page 1 of 1

scan fidelity to film contrast curve

PostPosted: Sat Jan 30, 2010 6:00 am
by newedb
I am using Plustek 7500i with Silverfast SE Plus.

As far as I know, the film profiles in NegaFix have their own builtin contrast curves. since each film already has its own curve, the outcome will have two curves overlapped.

If I want to preserve the film curve, don't want the film profiles' curve, what file profile should I use? Is the linear profile has a linear contrast curve?

Re: scan fidelity to film contrast curve

PostPosted: Tue Feb 02, 2010 5:37 pm
by LSI_Morales
Newedb

newedb wrote:As far as I know, the film profiles in NegaFix have their own builtin contrast curves.


It is right but I would call it a response curve

newedb wrote:since each film already has its own curve, the outcome will have two curves overlapped.


That is partially right. Every film has its typical sensitometric curve but that indicates how the negative film will react. However you do not only want to have the pictures as negatives, you want to positivate them and usually that is done on another support (regularly paper).
Those supports are also light sensitive materials which have their own sensitometric curve, in order for that to work accurately, there must be a calibration of the media that will make that positivation.

Since you want to digitize your pictures as positive, you need a calibrated profile so the scanner knows how to interpret a determined emulsion, that is exactly when NegaFix comes into the game.

newedb wrote:If I want to preserve the film curve, don't want the film profiles' curve, what file profile should I use? Is the linear profile has a linear contrast curve?


The linear profile does not have a curve (it is linear)

Cheers

Re: scan fidelity to film contrast curve

PostPosted: Thu Feb 04, 2010 6:02 pm
by newedb
LSI_Morales wrote:Newedb

The linear profile does not have a curve (it is linear)

Cheers


Thanks for replying my question.

So does this mean, if the Gamma is set to 1.0 and the linear profile is used, the scan result will have a contrast curve faithful to the negative film's curve?

Re: scan fidelity to film contrast curve

PostPosted: Fri Feb 05, 2010 9:22 am
by LSI_Morales
Hi newedb

newedb wrote:So does this mean, if the Gamma is set to 1.0 and the linear profile is used, the scan result will have a contrast curve faithful to the negative film's curve?


It means the scan will have no contrast other than that obtained from the film. In other words, no gradation curve will be applied.

However you should have in mind that every scanner has a special response to every film (positive or negative), it is not (and can not be) 100% faithful to the negative characteristics.

Cheers