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02-14-2012, 04:45 PM   #1
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Provia 100F - Removing blue color cast

Just got my first few rolls of Provia 120 slide film back from processing. (Will post pics soon!)

Scanning my first frames I noticed a really strong blue color cast (even a bit purplish). At first I thought it was the scanner needing to be better profiled but then some other frames under full sunlight came out with a much better color balance. Anyways, I've since learned that under overcast light Provia film is known to take on a blue cast.

Sunlight North of 60 in the winter is pretty cold to start with, and I've been shooting a lot of overcast, early or late light which makes it worse. Plus everything is covered in snow which comes out totally blue. Some of my frames have a fairly extreme cast to them.

I can correct this in the scan or in lightroom but thinking in terms of my film, I could use a warming filter on the camera when shooting under that kind of light. Anyone recommend which number of filter I should try?

I can post some examples tonight if it helps.

02-14-2012, 04:58 PM - 1 Like   #2
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The change of colour temperature during the day is so vast I don't think any single filter can cover them all. But 81B should be a good starting point.
02-14-2012, 05:46 PM - 1 Like   #3
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QuoteOriginally posted by adelorenzo Quote
Just got my first few rolls of Provia 120 slide film back from processing. (Will post pics soon!)

Scanning my first frames I noticed a really strong blue color cast (even a bit purplish). At first I thought it was the scanner needing to be better profiled but then some other frames under full sunlight came out with a much better color balance. Anyways, I've since learned that under overcast light Provia film is known to take on a blue cast.

Sunlight North of 60 in the winter is pretty cold to start with, and I've been shooting a lot of overcast, early or late light which makes it worse. Plus everything is covered in snow which comes out totally blue. Some of my frames have a fairly extreme cast to them.

I can correct this in the scan or in lightroom but thinking in terms of my film, I could use a warming filter on the camera when shooting under that kind of light. Anyone recommend which number of filter I should try?

I can post some examples tonight if it helps.
I use a Skylight filter anytime I'm shooting colour slide film.

Phil.
02-16-2012, 11:13 AM   #4
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Here are a couple of examples of what I am talking about.. I realize I can correct these in Vuescan or Lightroom but it would be nice to try and get it right on the slides. Both were taken in late-day, overcast lighting conditions.

[ original scans replaced on Flickr ]


Last edited by adelorenzo; 02-18-2012 at 10:14 AM.
02-16-2012, 11:21 AM - 1 Like   #5
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QuoteOriginally posted by adelorenzo Quote
Here are a couple of examples of what I am talking about.. I realize I can correct these in Vuescan or Lightroom but it would be nice to try and get it right on the slides. Both were taken in late-day, overcast lighting conditions.





A skylight filter will help and I always use the when shooting slide film.

The Skylight (KR 1.5) filter absorbs excess blue which is present in daylight, and thus produces a warmer color tone. At the same time, it blocks UV rays, and reduces the haze around distant objects.

Skylight filters for analog photography with slide film have a very pale amber tint and act like a UV filter to cut out ultraviolet radiation. In addition, they eliminate the bluish hue in shadow due to the indirect light from the blue sky. This color distortion is particularly unpleasant on skin. A skylight filter should only be used if the entire motif is in the shade. For the areas lit by direct sunlight will also be subject to the amber filter even though they do not have any bluish hue – they then turn amber. For this reason, a skylight filter should never be used for front-lens protection (use a neutral UV filter instead).

Skylight filters do not have hardly any visible effect on b & w images and they are not necessary in digital photography, because of the light color variance can be eliminated also by the white balance of the digital camera or later on by an imaging software.





Phil.

Last edited by gofour3; 02-16-2012 at 11:39 AM.
02-16-2012, 11:55 AM - 1 Like   #6
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Overcast, snow, and slide film. That's gonna be blue for sure.

Skylight is classic for snow. I wouldn't try 81B, it will make your snow a wierd pink. Very difficult to get it just right with film, so i'd rather do less and have some blue which is expected in snow, than have an overall normal scene but with pink snow.
02-16-2012, 01:16 PM - 1 Like   #7
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QuoteOriginally posted by adelorenzo Quote
Here are a couple of examples of what I am talking about.. I realize I can correct these in Vuescan or Lightroom but it would be nice to try and get it right on the slides. Both were taken in late-day, overcast lighting conditions.
Hi

I've done a lot of slide shooting, including Provia, under exactly those conditions. The colour cast in your samples goes well beyond what I would expect to see. As well, the contrast is quite high given the lighting conditions.

Therefore it looks to me like part of the problem is scanning. Scanning software left to itself tends to increase contrast and exagerate colour casts in shots of this type. You have to make manual corrections to compensate. Some scanning software has an eyedropper function that allows you adjust neutral tones quite easily. Further corrections can be made in your image editing software. For me colour correction of snow scenes is often a two-stage process- fix the worst of the problem in scanning, then fine-tune in Photoshop.

If you want to use filters, that sort of lighting requires more correction than you get with a skylight filter. I've had good results with a Heliopan KR3. However, there is the risk of image degradation from using a filter. Even the Heliopan produced weird internal reflections in one of my wide lenses.

In extreme cold you can run into interesting complications. For example, when attaching a filter at -40 water vapour from bare hands can freeze on the filter and cause fogging which yu won't notice until it's too late. (sigh)

As light changes during the day and as clould comes and goes, there is no simple fix in terms of one filter fixing eveything.

In my experience colour correction of this sort of probelm is done more effectively through good scanning and image editing practices than through use of warming filters.

Hope this helps.

John
02-16-2012, 04:12 PM   #8
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Thanks everyone for the helpful responses.

I seem to recall seeing a good quality skylight filter in the bargain bin at the local shop so maybe I'll give that a shot first.

Yes, there are definitely some scanning issues as well. I am brand new to this and only just learned how to adjust white balance on the scan. (Right click in Vuescan, who knew?) I was also messing around with the curves, hence why everything looks so contrasty. Working on a laptop sometimes you go overboard, now seeing them on a full monitor I'm kind of 'ick.' Going to try re-scanning and will post results.

02-17-2012, 12:53 PM   #9
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QuoteOriginally posted by adelorenzo Quote
Going to try re-scanning and will post results.
Good, because I really like these pictures.
02-17-2012, 03:48 PM   #10
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Well, here is the result with doing a better job white balancing the scan. Better but still not perfect.

[ second scan got updated on flickr ]

The second one came out less purple but still there. If I totally jacked the white balance in Lightroom it looked odd so I decided to leave it here:




I'm pretty sure it is just the slide film + light combination, as shots from the same rolls in better light are coming off the scanner with perfect color, no adjustments made. For example these two photos have almost no processing or color correction:






Last edited by adelorenzo; 02-19-2012 at 09:43 AM.
02-17-2012, 04:29 PM   #11
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I like the color rendition of these last results. That touch of violet is nice and works well, I think.
02-18-2012, 07:12 AM   #12
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They're still pretty weird. Try this:

With the top image, make a curves adjustment layer in Photoshop, and, using the eyedroppers, select the whitest snow as the white point (maybe the snow on top of the oil drum). Then select the black in that cavity beneath the oil drum as the black point. Finally, select a mid-toned brick as grey point.

You should see an improvement straight away. Proceed from there until it is close to how you want it.
02-18-2012, 09:59 AM   #13
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I don't use photoshop but then I remembered the HSL sliders in lightroom. I don't normally use them. I adjusted the yellow, green and purple luminance values and that seemed to help.


02-18-2012, 11:46 AM - 1 Like   #14
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That last version looks much better. The others remind me of underexposed Ektachrome from the 60s and 70s.


Steve
02-18-2012, 12:36 PM   #15
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Hi. I've taken the liberty of working on two of your shots a little in Photoshop. Nothing very fancy, just ran autocolor and tweaked with color balance, hue/saturation, curves and highlight/shadow. There are still minor bits of weirdness but I think you'll find these are closer to the original scene than earlier versions. It's interesting to note that in the oil tank shot the snow has a green cast due to reflection from the green wall.

John


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