Dear Rusell
Dear Mathsartist
Dear SilverFast users
NegaFix is a tool created with the goal of offering users "more control over the tonal range and values of the image" when scannig negatives.
Every single profile included there was created using a special targets used to calibrate printers in professional labs, those targets and calculation tables contain a very precise measurement of the density for every film type.
I have taken a look at Rusell description of the "problem", and found that there are many points where Rusell is not using the NegaFix features appropriately.
In the first place, he is using the Image automatic included in both, NegaFix dialog and the main setting window in SilverFast. He argued that he activated and then deactivated the "Auto" feature for limiting the expansion of the Histogram in every channel, then he claim to have moved the limits to the right. He also shows us the histogram he used when scanning the film with the possitive.
However, Rusell did not move the limits to the left side of the expansion of the histogram included in the NegaFix dialog, as a consequence, he left the gray point in a darker place within the histogram. Hence the high contrast in the image.
Its important to know that the histogram in the NegaFix window is inverted as the one present in the main window (because it is a positivation of the original scan which is negative).
In such cases, you can actually reset the auto tolerance by presing the "reset" button next to it, you can then place the limits of the histogram as desired as you would in the main settings window.
Another important thing to acknowledge, is to deactivate the color cast removal, within the options dialog, under the "Auto" tab. Another tool that should be deactivated is the "Image-Automatic" so the contrast limits and gray point will not be set by the program.
We have a very complete document about NegaFix, and the possibilities to use its extended features (which are only available in SilverFast Ai), please check the following document:
http://www.silverfast.com/download/docs ... Fix-en.pdfYou can also find some isntructive videos at:
http://www.silverfast.com/download/movi ... -08-09.movhttp://www.silverfast.com/download/movi ... -05-13.movhttp://www.silverfast.com/download/movi ... -08-12.movhttp://www.silverfast.com/download/movi ... -11-28.movLeast but not last, if you want to use the maximum dynamic range of your film negatives, you should make sure to scan your film in 48 bits color and not 24 bits (as Rusell did) which will again limit the quality of your image.
If you definietely do not want to use NegaFix but still want to make the most of your negative film, you still can scan in 48 bits HDR and save as a TIFF file, your negatives will be scanned to the most of your scanner capabilities and the resulting files will be untouched, no effects or corrections will be applied to them. Those files can then later be edited in your favorite suite.
As a conclussion we could not only say that NegaFix can be manipulated as desired by users (of course it requires users to instruct about its capabilities and experiment with its posilities), but essentially it can be completely turned off (as desired by some users and as the main topic for this forum thread!).
Greetings