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Thread: Mixed white balance

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DenisSS

Posts: 1307
Location: Nigeria
Registered: 2 Sep 2010
Mixed white balance
Posted: 3 Sep 2009 at 22:56 GMT
updated: 2 Sep 2010 at 20:27 GMT
I have just finished putting - or nearly putting - together this Aurust centre tour, but have had a couple of instances where the white balance was mixed between artificial and natural light sources, as in this one, where the light from the door has a particularly bluish quality:

photonorge.com/panoramas/aukrust/11.html

I know this isn't the end of the world, and in other images I have created another layer to adjust for the blue-tinted areas and painted out the remainder. Those were quite easy, since the shades were quite similar. However, it was a huge amount of work, neverthless, and with this one, it just looked wrong that I decided this was the best solution.

Does anyone have advice they can give me for working with mixed light sources? Especially when there is a huge mix (as in this project) of natural, tungsten and fluorescent . . .

I await with trepidation for a good anwser before I go to Paris for a shoot next week.

smile smile

Jon
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michael medina

Posts: 385
Location: portland, oregon, United States
Registered: 27 Jan 2008
Re: Mixed white balance
Posted: 3 Sep 2009 at 23:58 GMT
since there's no other blue in the scene, just desaturate the blues using the appropriate range in the saturation tool. if they look too grey after that, maybe add some back and change the hue a bit. you can try the same thing with selective color, but you can't choose the color range like in the saturation tool.
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Hans Nyberg

Posts: 2874
Location: Denmark
Registered: 28 Aug 2005
Re: Mixed white balance
Posted: 4 Sep 2009 at 11:04 GMT
Jon

You should really try to avoid sharpening your images too much. It is very ugly and especially as you do not use high quality for the panning you get a very irritating shimmering effect.

Sharpening should be zero when converting from raw and you should only apply it on the final pano. Use 0,4-0,5 radius and not more than 200% unless you have an old Sigma 4.0 or other lens which is very soft.

It makes a large difference also in compressed download size.

Hans
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DenisSS

Posts: 1307
Location: Nigeria
Registered: 2 Sep 2010
Re: Mixed white balance
Posted: 4 Sep 2009 at 11:17 GMT
updated: 2 Sep 2010 at 20:27 GMT
Good advice Hans, thanks!

Jon
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iam360Texas

Posts: 327
Location: Fort Worth, Texas, United States
Registered: 12 Jul 2006
Re: Mixed white balance - More
Posted: 4 Sep 2009 at 13:19 GMT
updated: 4 Sep 2009 at 13:23 GMT
Mixed light is a some what a simple issue to resolve.

We shoot canon .cr2 raw Sigma 8mm 4 images around on the horizon. In mixed light, we use a WhiBal White Balance Reference Card. Photo Shoppes sell an expensive 18% gray card. Your camera needs to record "What is Grey" or what is white in your image. The reference card is a way to telling the camera 'this is a known white or gray'.

Our 1st click stop image at 0° we place the Gray Reference card in a position where most all the incoming light is reflected off the card back to the camera lens/sensor. Often this it is on the floor or ground.

Our 2nd image is also at 1st click stop image at 0° only with the grey reference card removed. 3rd 4th and 5th image and so on around the horizon.

We use Photoshop CS4 and Adobe Camera Raw Converter [free] (ACR) to convert the raw images to TIF's. In ACR we select all 5 images to load at one time. Now the gray card image is at the top.. and the real 4 images are below. Tag click the top image so it will be in the view window, then click the [SELECT ALL] button so the changes will affect all images.

Click select the White balance eye dropper and mouse over and click on the picture of gray card in the image. NOW all 5 images have the same white balance value.

While in ACR also make Chromatic Abberations adjustments.

DESELECT all 5 images. Now tag select 4 images and save them to your hard drive as 16bit TIF's.
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tturner

Posts: 218
Location: Dallas,TX, United States
Registered: 28 May 2006
Re: Mixed white balance - More
Posted: 4 Sep 2009 at 14:26 GMT
Dave's tutorial above is great advice but if the offensive light source is not hitting the grey scale target it makes no difference. I use the replace color tool to remove the unwanted color. Select the area to change and use the fuzziness slider to fine tune the area affected then adjust the sliders (hue, saturation & lightness) to taste. If the same color is needed in other areas of the pano just magic wand or lasso the offensive area then do as above to only change that area.

Learn new trick- Hans is it not good to sharpen the image in ACR. I have been sharpening there and in the final as needed. Will try this on next editing session.

TTurner
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Pete Loud

Posts: 398
Location: United Kingdom
Registered: 14 Oct 2006
I use Auto WB
Posted: 4 Sep 2009 at 16:49 GMT
updated: 4 Sep 2009 at 16:56 GMT
I go completely against the conventional approach of using a fixed white balance. I do nothing. I use auto white balance and let PTGui merge the different colour casts.

Here is an example of a pano shot in an environment with daylight, flourescent, incandescent, mercury and probably a few others sorts of lighting too.
www.peterloud.co.uk/photos/Newcastle/Grainger_Mar...
It was probably helped by my using a 10-20mm lens so that my pano was made up from many images, hences giving gradual changes.

Here's another, daylight & incandescent lighting, done on auto WB.
www.peterloud.co.uk/tunebook/Turks_pano_2.html


Pete
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Ken Warner

Posts: 821
Location: Mammoth Lakes, United States
Registered: 14 Aug 2004
Re: I use Auto WB
Posted: 4 Sep 2009 at 17:12 GMT

Pete Loud said:

I go completely against the conventional approach of using a fixed white balance. I do nothing. I use auto white balance and let PTGui merge the different colour casts.
Pete


That's an interesting idea. Just let the colors be the colors they are. I kind of like that. Less anal...
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Piotr Maciak

Posts: 75
Location: Switzerland
Registered: 6 Mar 2009
Re: Mixed white balance
Posted: 4 Sep 2009 at 19:22 GMT
In situations like this, I set the white balance so that the dominant light source is rendered correctly. Then I use "White Neutralizer" filter from the Color Efex Pro 3.0 filter set to deal with color casts. It is extremely effective and easy to use. The U-point technology basically eliminates the need for time consuming masking. Color Efex Pro 3.0 is available as a plugin for both Photoshop and Capture NX2.

Piotr
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Doug Aurand

Posts: 3282
Location: Albuquerque, NM, United States
Registered: 2 Jan 2008
Re: Mixed white balance/Expodisc
Posted: 12 Sep 2009 at 15:28 GMT
I got a 77mm Expodisc last week and used it on the hotel virtual tour and still photo shoot I just got back from.

I got the 77mm to fit my Canon 10-22mm Wide Angle Zoom, but it will work on my Sigma 8mm too

I just put the Sigma's ring/hood on the lens without the lens cap and hold the Expodisc in place. The inner bevel of the Expodisc that fits inside the 10-22mm is almost the same size as the Sigma's ring/hood.

I've had the most trouble with scenes like Lounges and Restaurants with low light from mixed light source types. The Lounge had tungsten/incandescent and compact fluorescent. The Restaurant has tungsten/incandescent, compact fluorescent and natural sunlight

By aiming partially at the dominant light source, but making sure the other lights are in the FOV, I got really good color in both the stills and virtual images..

In the Guest Rooms I solved part of the problem by taking 5000 to 5500k compact fluorescents with me and changed the all the bulbs in the lamps so I didn't get a room that the camera used sunlight as the dominant light that had orange/yellow lamps.

Doug Aurand
Albuquerque, NM
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