To me the color temperature is part of the demosaicing process. Based on the values of the raw data a certain correction is done on the channels to get the right colors. If you don’t do that you’ll have wrong colors. How can the demosaicing proces been done without a colortemp???
There’s more.
A fresh picture, no correction. Raw is disabled but shows 5400K. I enable raw, as shot 4579K. I disable raw, temp doesn’t change, histogram doesn’t change.
It seems raw is enabled while it shows disabled. And the color temp and tint are from “as shot”.
Most sensors only read one colour in one place with one photosite. In order to get a multicoloured image, photosites that read different colours are arranged side by side in the image plane. Because we cannot have more than one photosite in one place, the missing parts are interpolated while demosaicing. Colour temperature or white balance don’t matter during this process which is like creating a map, all you want to know is, if there is water, desert or forest, but the kind of trees you’ll find does not matter at that stage…
Each sensor maker builds photosites with a manufactured, known response to daylight, flash, tungsten light etc. and derives, from these responses, the multipliers for the respective colour temperatures. Said multipliers are then stored in the camera’s firmware and applied according to the WB you set in your camera.
Whatever WB you set in your camera, the sensor will always deliver the same value per photosite and only the software, be it in camera or on the PC, will calculate the image from the photosite values and the WB dependent multipliers.
DxO measures these responses under different lighting conditions - and you can find many results like this example on dxomark.com
It was a rethorical question.
In contrary to what the pallets suggest, one can’t disable the wb tool. Even if it shows disabled it’s using a color temp “as shot”. But when ‘disabled’ it shows a wrong temp. Enabling will show you the right temp. A reset or disabling the tool will not change that temp. Only a reset, leaving the picture and going back. Call it a bug. Doing the right thing but showing a wrong value.
It took me some time to find out what was wrong.
On my Mac and using the preset “No Correction”, WB is disabled and displays WB according to camera settings. When I switch to a new image, WB goes to 5400 for a split second, but does not do it any more, once that DPL has calculated the previews in the background.
That’s correct. Enabling does show me the right temp. Disable it again doesn’t change the temp again. But leaving the picture and coming back it shows 5400 again.
Leaves me with the question what disabling or enabling means. One can’t disable colortemp in a demosaicing proces. So show it without that choice and show the right,used, color temp.
Bot my 8.1 and 10 pc’s act the same.
It should show 3381 immediately, that’s the temp that is used. You will not see the picture or histogram changing when you select raw or not. It seems in the mac version the 3381 is shown immediately. Reading Platypus the update from initial value to used value is not done in this case on the win pc.
Platypus,
You’ve a Mac. Just curious. Open an image, change the temp to 10000. When you diasble raw you’ll see the image with the temp “as shot”. Does the temp info change to?
When you disable WB palette, the temperature goes back to the default value (but you should not expect any visualization in the preview or Histogram as it does not affect the image because the palette is disabled). But as soon as you enable the palette the auto value will be recalculated and you should see the calculated value (3318 for our example).
Can I just ask why, when my Nikon D810 is set to manual WB 5600°K, on selecting an image for the first time, the temperature flickers to 5400 then settles at 5510?
This happens whether I activate the WB palette for “as shot” or even if I leave the palette deactivated.
Dear Svetlana,
that’s not what I noticed.
Enabling WB palette changes the value from 5400 to the WB the photo was taken…in my case 3381
Disabling WB palette does not change back the value to 5400.
Only when I leave the focus to another photo and come back again I will see the 5400
The histogramm does not change during enabling disabling but when changing setting, temperature or tint
My test cases 1 to 6 are as described.
Yep, 5400 is the default slider value. When you enable WB the value is recalculated according to the image calibration. When you disable WB the sliders values are updated with image re-selection.
The default value of the WB Temperature slider = 5400°K, but as you know it’s the correction which is calculated individually for each image based on the calibration - that is why you see 5510K for your image. Unless you question is why it’s not 5600 as set in the camera. In this case we need an assistance from @Marie.
@Joanna
Probably PL initiates the variable with a number 5400 to be sure it’s numerical. I think. That should be replaced with the actual temp. It’s just not done in a elegant way.
The difference between the manual in-camera wb and the wb in PL I can’t explain. I just didn’t investigate that. I don’t know what is written in the exif. Probably PL is just calculating it by itself and means “as shot” based on the raw data and not camera setting. Try an extreme different manual wb in your camera, let’s say 10000, and see what PL does.
On further investigation, using Exif Editor, in the advanced camera data, the WB is simply marked as 1, which appears to be the equivalent of “Daylight” or 5400.
Using Apple’s own Preview app shows Nikon specific data of 5600K, but this is obviously not read in either Exif Editor or DxO.
But nowhere can I see any reference to 5510, which is what DxO ends up showing.
In PhotoLab and in other photo softwares temperature displayed in user interface doesn’t correspond to setting of cameras.
Reasons of that are:
it’s not possible to get precise temperature/tint applied by a camera at shoot when a white balance preset is selected because cameras adapt WB even with preset and in litterature only range of temperature are given.
different models of cameras (especially with different brands) won’t give the exact same temperature/tint for a shoot of the same scene with the same light
About White balance presets:
In photo softwares temperature and tint displayed are just a scale to help adjustment. So, in PhotoLab, temperature/tint have been fixed for presets displayed. So when processing images from different cameras there will be no discrepancies.
About temperature and tint:
PhotoLab, as any other rawconverter, use White Balance given in Exif. To be accurate it uses White Balance scales (coefficient to apply in rawconversion to get same white balance as camera).
In camera profile we have white balance scale for all preset given previously (cloudy, tungsten, …).
So when a photo is put in PhotoLab it looks to white balance scales, apply them and do a calculation to estimate temperature and tint associated compared to scales in camera profile. This calculation is specific to any rawconverter that’s why every converter from different company will provide different temperature / tint associated to an image.
indeed.
