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Author Topic: white balance on color negatives scanning vs. removal of the orange cast  (Read 840 times)

EinstStein

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I saw suggestions to use the white balance drop to click on the negative orange border, and implies that is the white balance.

Correct me, but I think there are two issues in white balance. The first is the color negative orange base (border) color, which has no clue of the lighting condition during the exposure.  The second is the light condition during the exposure.

Assuming the negative has a grey card reference in the picture, another way to do the white balance is to click the white balance drop on the grey card.  But this method may still have a problem. I assume the grey card method was handled by de-coloring the whole scene assuming the orange cast was proportional to the brightness of each pixel, not a uniform constant across the whole scene.

In another word, this is a two variables problem.

How is it handled by the scanner software? How professional film scanning experts handle it?


 
 
   
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Bart_van_der_Wolf

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I saw suggestions to use the white balance drop to click on the negative orange border, and implies that is the white balance.

Correct me, but I think there are two issues in white balance. The first is the color negative orange base (border) color, which has no clue of the lighting condition during the exposure.  The second is the light condition during the exposure.

Assuming the negative has a grey card reference in the picture, another way to do the white balance is to click the white balance drop on the grey card.  But this method may still have a problem. I assume the grey card method was handled by de-coloring the whole scene assuming the orange cast was proportional to the brightness of each pixel, not a uniform constant across the whole scene.

In another word, this is a two variables problem.

How is it handled by the scanner software? How professional film scanning experts handle it?

Hi,

Neutralizing the Color Negative Mask color, and Color Balancing. are two distinctly different things.

Good scanner software (such as VueScan Pro) works together with the scanner hardware, which should allow using different exposure times for the Red, Green, and Blue scan channels. By balancing the exposure times, one can neutralize the Color Mask. With Yellow/Orange masks, that would mean that the Green channel exposure time needs to be boosted the most (which also improves the S/N ratio, i.e. produces a cleaner Green channel).

From that point on, basically a curve inversion to positive needs to be done, and only then can the color balancing and tweaking commence.

Cheers,
Bart
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== If you do what you did, you'll get what you got. ==

saiguy

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SilverFast scanning software has a tool called NegaFix. That tool has many profiles for many films. If you know what film you are scanning you just choose that film type profile. If you don't know the film type you try different profiles till you find one that does a good job.
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digitaldog

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+1 for SilverFast. The solution is one based on dealing with color negs and the orange mask. IOW, it's far more than simple WB or inverting.
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Andrew Rodney
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Which negative film scans better than others as far as getting the colors right?  Which software are you using? Showing samples would be helpful.

saiguy

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Alan.  Go to SilverFast web site and watch their short video on NegaFix.
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Alan Klein

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Alan.  Go to SilverFast web site and watch their short video on NegaFix.
Thanks for your response but I didn't ask about Silverfast in particular.  Also, I'm not interested in a promotional video from a software manufacturer trying to sell a product but rather real world answers from photographers who have scanned film.

Let me repeat my questions:
Which negative film scans better than others as far as getting the colors right?  Which software are you using? Showing samples would be helpful.

digitaldog

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Thanks for your response but I didn't ask about Silverfast in particular.  Also, I'm not interested in a promotional video from a software manufacturer trying to sell a product but rather real world answers from photographers who have scanned film.
At least on Photographer who scans film answered that question with respect to SilverFast.
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Andrew Rodney
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Alan Klein

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I don;t usually shoot negative color film.  But I pulled out 25 year old Agfa Ultra 120 6x7 shots I took then. I just scanned them with an Epson V600 running Epsonscan on Color Correction gamma 2.2, Auto Exposure level midway, unsharp mask checked, 48 bit color, 2400dpi resolution, saved as tiff.  No edits in post except converting to jpeg and reducing resolution for the web.  The colors are slightly saturated.  But that's to be expected with Agfa Ultra.  BUt I don't see an orange mask.  I do see a black line running vertically.  Maybe someone can tell me what that is? 

In any case, Epsonscan seems to handle the orange mask.  Comments?

digitaldog

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In any case, Epsonscan seems to handle the orange mask.  Comments?
Of course it does, or it would be orange  ;)
The question becomes, how well, with how many differing kinds of color negs OR the same kind but with different densities due affecting that mask.
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Andrew Rodney
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Alan Klein

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Here's another one with same settings.  This one is Portra 400.  I see I still have the black line horizontally.  No orange mask that I see.  Why are people going to extremes with trying to eliminate the mask if Epsonscan does it?  Why reinvent the wheel?


digitaldog

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Here's another one with same settings.  This one is Portra 400.  I see I still have the black line horizontally.  No orange mask that I see.  Why are people going to extremes with trying to eliminate the mask if Epsonscan does it?  Why reinvent the wheel?
I understand you believe your testing is exhaustive in terms of image quality and color rendering from (All) color negs (with three tests).
ANY software that can scan negs should "Remove" the orange. There's no real trick to that.
As the late great Bruce Fraser would say: "If you're happy with what you have, be happy that you're happy with what you have!"
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Andrew Rodney
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Alan Klein

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I understand you believe your testing is exhaustive in terms of image quality and color rendering from (All) color negs (with three tests).
ANY software that can scan negs should "Remove" the orange. There's no real trick to that.

No it's not exhaustive.  I seem to recall I was having some problems at one time.  That was one of the reasons I like to shoot chromes.  You get what you got and know immediately if you also shot it at the right exposure.  PLus I like the color palette of Velvia 50.  So most of my shots are with it.  But I guess I'm questioning why people go to Silverfast or Vuescan if Epsonscan seems to handle the mask pretty well.  I understand if you use a digital camera to "scan".  Then you're stuck trying to come up with an algorithm that works.  But why not try Epsonscan if you're using their scanner?

Anyone got a fix to my line?  That's something new that I didn't have before.  It's the scanner because it's not on the film. 

digitaldog

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I understand your guess about SilverFast. That is why 2 of us here with experience with it (some decades) have posted about our experience. 😏
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Andrew Rodney
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Alan Klein

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I understand you believe your testing is exhaustive in terms of image quality and color rendering from (All) color negs (with three tests).
ANY software that can scan negs should "Remove" the orange. There's no real trick to that.
As the late great Bruce Fraser would say: "If you're happy with what you have, be happy that you're happy with what you have!"
I guess what I'm saying is why not try Epsonscan first.  If you get good colors, you're done immediately in a couple of minutes.  If on the other hand you have problems because of the film type, density of a particular shot,  or whatever, then switch to other software.

Alan Klein

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Black line.  Help?

degrub

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Is it in the direction that the scan head moves ? Then possibly a bad sensel or possibly dirt on the mirror/sensor head
If it is 90 degrees to the motion of the scan head, then 1) in the glass, 2) in the film, 3) electrical noise, 4) software/firmware. For 1, since this is a transparancy unit scan, try reversing the film (rotate 180 degrees, same orientation). For 2, if in film should follow the rotation, 3) scanner should be plugged into a electrical noise filter - UPS preferred, power bar, etc, for 4 try a trial version of Vuescan and see if it repeats.
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digitaldog

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Dead pixel or dirt.
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Andrew Rodney
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Alan Klein

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Dead pixel or dirt.

Where's the dirt?  Accessible or under the glass?

degrub

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Likely on one of the delicate mirrors that are mounted with the scan head if dirt.
Cleaning would be non-trivial as it is extremely easy to damage the mirrors. Economically not worth it for that scanner.

Try the tests i mentioned and see what change the line follows.
You can also see if it is related only to scanning transparencies or reflectives. Try a scan of a mat uniform color reflective and see if it shows up.


There is usually a fair amount of dust and other small particles inside a scanner. If you don’t mind replacing the scanner, as a last resort, you can lock the head, usually with a slider underneath or similar, and gently tilt the scanner on its side and give it a sharp rap to see of the spot moves. Not recommended, but last resort. I have heard of some turning it upside down and doing similar, but you have to take it apart to remove the scan glass plate. Otherwise, stuff just accumulates on it and falls back down on the scan head. Like i said, only if you are willing to replace the scanner.

If it is a single sensel on the scan head, but doesn’t show up on reflective scans, well, you may have to get something else to do transparancies.

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