Colour cast when scanning Portra and Ektar?

FishyFish

FishyFish

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I've noticed when I've scanned some colour negatives that they can have a noteable colour cast. Portra seems to be the biggest culprit, with a clear blueish tint, but I've had some similar results with Ektar too. I think this may be down to the film backing having a deeper orange cast that results in the blue tint when converted to a positive. I think I've found a relatively simple solution by using the Nik Collection Color Efex Pro 4 plugin though. There's a preset called Pro Contrast that has a "Correct color cast" slider, which seems to work pretty well, as in the examples below (this is Portra 400 - the first image is straight from the scan, the second image is the corrected one).

portra_before.jpgportra_after.jpg

I'm pretty happy with my new found solution, but wondered if anyone else has noticed this sort of thing, and if so, how do you go about correcting it?

Thanks.
 
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I've only ever used film scanners - are you using a flatbed? Neg scanning can be a dark art. Some scanning software is better than others!
 
The only solution that produced acceptable results for me was to let the lab worry about it.
 
Do you develop yourself. You get colour casts if the temperature isnt quite right
 
droj said:
I've only ever used film scanners - are you using a flatbed? Neg scanning can be a dark art. Some scanning software is better than others!
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Dad's dedicated 35mm film scanner had a load of presets for different colour neg emulsions and there was a marked difference between the files when different ones were selected. Can't for the life of me remember what it was though and since dear sister sold it when Dad died (because she knew I wanted it...) I can't find out now.
 
Different scanning software has different solutions for dealing with the varying colour casts from the orange base. For this reason, I too generally leave the lab to do my C41. However, I have done it in the past, using both Silverfast and Vuescan. If they have a "preset" for the film it generally works out ok. The other solution is to scan it as a positive (treat it like slide film) then load it into a Photoshop variant and from there into a plugin called ColorPerfect. This has a fantastic set of presets and is excellent, however it is not cheap.

I've a vague feeling that young Mr @Andysnap might have tried using a Raw editor as well. However, since he can't tell his left from right, let alone blue from red, that may not be much help... :D:D:exit:
 
H'mm on my monitor the 2nd one has a very slight magenta cast, anyway put the 1st in Photoshop adjusted gamma and used auto correct and it's lovely...well on my monitor but others might be different.
 
My monitor is overdue for calibration, but like Brian the second has a magenta cast on mine (look at the engine) whereas the first looks either neutral or possibly a pale green cast. I may be being unduly influenced by the pink/magenta umbrella.

As to the question of whether I get colour casts, I can't say that I've noticed any, but I'm scanning either Kodachrome or Fuji 160 when it's in colour. Very rarely either, although I have a lot of Kodachrome to do at the moment for an exhibition.
 
Ive nothing to add to the dupiscussion on colour casts, how about you @Andysnap?
 
RaglanSurf said:
Ive nothing to add to the dupiscussion on colour casts, how about you @Andysnap?
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Yes, being an acknowledged expert on all things colour, I believe that no colour casts exist. Just a plot to make us colour blind folk look foolish. :D
 
Hmm. It could be that I've ovecooked the slider and taken it too far. I can't see any noteable magenta cast on the shot (there may be a hint), and that's looking at it on my monitor and an iPad.

Maybe I ought to give the monitor a check to see if it's still calibrated ok - any recommendations on websites or software (I can't remember what I used before). Thanks.
 
The differences between the two version were very slight - I put them both into Photoshop and used the eyedropper to see what the RGB values were at places I thought should be neutral. Which does suggest a thought - some software can autocorrect colour balance by placing an eyedropper on a known neutral area. You have to be certain it is neutral though, as I've had very different results on the same scan (a colour faded Kodachrome) depending on which "neutral" I selected. As coloured reflections from objects in and out of the frame can give localised colour casts, there are practical difficulties whatever you do. Unless you include a grey card in a test shot for the lighting.
 
FishyFish said:
Hmm. It could be that I've ovecooked the slider and taken it too far. I can't see any noteable magenta cast on the shot (there may be a hint), and that's looking at it on my monitor and an iPad.

Maybe I ought to give the monitor a check to see if it's still calibrated ok - any recommendations on websites or software (I can't remember what I used before). Thanks.
Click to expand...

As a suggestion you could do what I did many moons ago would be to download a colour chart (I used it to check my printer)..the one I downloaded, had a picture of a baby etc and different scales of colour and IIRC tones for B/W, so if everything looks great then your monitor is OK. If I ever come across the download will post...come to think of it I haven't seen the colour chart print for a long time, must be around somewhere :(
This might be it http://www.pcstats.com/articleimages/200601/samsungspp2040_300dpi1orig.jpg as a starter
 
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Downloaded the colour chart and everything looks great. First photo looks a bit on the cool side, second one has a slight but definite magenta cast to it according to my monitor (a 12 month old 24" Samsung) and eyes. I'd imagine somewhere around just less than half way between the two photos might be about right?
 
The colour chart image looks fine on my monitor - the only possible issue being the 18 & 19 on the grey scale bar are indistinguishable.

Here's another Portra 160 shot.

1 - Original scan
aaa_original.jpg

2 - 50% colour cast reduction
aaa_50_percent_tint_correction.jpg

3 - 100% colour cast reduction
aaa_100_percent_tint_correction.jpg

I think the 50% image is probably the best out of the three - although it could maybe take a little more adjustment - it still feels like it has a hint of blue (but that might just be reflected light considering the blue sky). The 100% image looks to be a little too warm perhaps. This is all to "my eye" though, and I guess that unless you're an expert, a lot of this is subjective.

It only seems to be Portra (and maybe Ektar) that gives me the blue tint. I don't notice it with any other images on my PC, and other colour films don't have it (although they can have their own characteristics - e.g. Poundland Agfa tends towards magenta to my eye). I'm relatively confident that it's Epson Scan that's the cause. After a bit of Googling, there are a number of other people reporting similar results.
 
Sectionate said:
Who do you us now that UKFilmLab is now CanadaFilmLab?
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Assuming you meant "Who do you use...", Filmdev is quite popular on here. 135 C41 £5 for dev and medium res scan.
 
FishyFish said:
The colour chart image looks fine on my monitor - the only possible issue being the 18 & 19 on the grey scale bar are indistinguishable.

Here's another Portra 160 shot.

1 - Original scan
View attachment 107160

2 - 50% colour cast reduction
View attachment 107158

3 - 100% colour cast reduction
View attachment 107159

I think the 50% image is probably the best out of the three - although it could maybe take a little more adjustment - it still feels like it has a hint of blue (but that might just be reflected light considering the blue sky). The 100% image looks to be a little too warm perhaps. This is all to "my eye" though, and I guess that unless you're an expert, a lot of this is subjective.

It only seems to be Portra (and maybe Ektar) that gives me the blue tint. I don't notice it with any other images on my PC, and other colour films don't have it (although they can have their own characteristics - e.g. Poundland Agfa tends towards magenta to my eye). I'm relatively confident that it's Epson Scan that's the cause. After a bit of Googling, there are a number of other people reporting similar results.
Click to expand...

....all subjective as really it is how you want your shots to look like..erm but I don't think a shot of a woman's face, using Portra, scanned with your 550 would look flattering with a blue cast :eek:
 
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If that's on a white canvass then I'd say there was a definite magenta cast.


;)
 
Well could be negatives, Happy to scan them for you on our Noritsu and Frontier 3000 to see the difference :)
 
Not seen any issues with scanning ektar. I always seem to get pretty good colours when using my V750 and vuescan.

v2


Portra 160 seems to have a mild purple tint to the blues.

 
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