Orquid "Phoenix"

Orquid "Phoenix"

by ceinmart

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I already learned that on raw images no white balance transformation has been applied yet.

1) If Aperture develops the preview images (without manually setting the WB by the user) it has to decide on some WB. This means Aperture has to either use some kind of automatic white balance algorithm (like the camera dos) or use some fixed values?

2) Can I somewhere see, which temperature and tint Aperture has automatically chosen to develop the raw image preview? The "White Balance" check box under "Adjustments" is per default unchecked and always contains the values "2861" and "14" for temperature / tint (which were obviously not used).

3) The raw images metadata contains a field "White Balance" that is e.g. set to "Auto White Balance" - but it does not seem to contain the WB settings the cameras AWB algorithm has chosen. Does Aperture respect the WB metadata in any way?

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If your camera is on auto white balance, it chooses the white balance and stores the information in the raw file. Aperture uses this information by default. The user interface is buggy, but if you select the "white balance" check box, and then click the "reset" button, you will have the original white balance settings and you can read the values that were chosen by the camera. –  Jukka Suomela Jan 31 '11 at 20:48
    
You can also double-click any adjustment slider in Aperture to reset it to the default value. For the color temperature, this is the value the camera recorded into your RAW file. –  ieure Jan 31 '11 at 23:23
    
Thank you Jukka & Ieure, that is the answer. For some reason Aperture sometimes forgets to update the displayed temperature/tint. If you then activate White Balance adjustment, it uses the wrong displayed values. Pressing "Reset" restores the right values which come from the cameras Auto White Balance algorithm and are stored in the EXIF tags "WB Red Level". –  Stiefel Feb 1 '11 at 17:42
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2 Answers

up vote 5 down vote accepted

Seems to me Aperture 3 does respect the WB settings of the camera. Shoot a scene with three different WB settings and you'll see three different results in Aperture previews. If you want to prove it further to yourself, or disprove my assertion, shoot with a manual WB and see if that passes through to your preview.

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Your assumption is totally right. The problem was a bug in Aperture, see the comments to the question. –  Stiefel Feb 1 '11 at 17:43
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I can't confirm this, but I would expect it to use the "Color Temp As Shot" or "Color Temp Auto" values recorded in the EXIF data.

For example: Using Jeffrey's Exif Viewer look in the "MakerNotes" section.

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I checked using Jeffrey's Exif Viewer. The raw file does not contain "Color Temp As Shot" nor "Color Temp Auto". But it contains "WB Blue Level", "WB Green Level", and "WB Red Level". Aperture converts those back to temperature/tint correctly - but sometimes forgets to update the UI if you switch between pictures - which leads to weird results. –  Stiefel Feb 1 '11 at 17:46
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