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Author Topic: Setting White point in RAW  (Read 1796 times)

JerryReed

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Setting White point in RAW
« on: January 05, 2008, 07:38:19 am »

Most of the images that I make are shot in the studio on a 16-shot digital back, where I have a GreTag Macbeth Color Checker in the scene to use as a reference.  My practice is to increase the lighting until I achieve 230-235 on the white square, knowing that I can print that value (white with some detail).

Now the question, I sometimes have a bit of space to the right of the first observable highlight data in the Tif files' histogram, with a LEVELs adjustment layer and holding down the OPTION/ALT key while dragging the highlight slider to the left until the screen shows the first pixels light up.  The meaning that I take from this observation is that there are no RGB data to the right of that point.

Is that a correct understanding?

Jerry Reed
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walter.sk

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Setting White point in RAW
« Reply #1 on: January 05, 2008, 04:05:31 pm »

Quote
Most of the images that I make are shot in the studio on a 16-shot digital back, where I have a GreTag Macbeth Color Checker in the scene to use as a reference.  My practice is to increase the lighting until I achieve 230-235 on the white square, knowing that I can print that value (white with some detail).

Now the question, I sometimes have a bit of space to the right of the first observable highlight data in the Tif files' histogram, with a LEVELs adjustment layer and holding down the OPTION/ALT key while dragging the highlight slider to the left until the screen shows the first pixels light up.  The meaning that I take from this observation is that there are no RGB data to the right of that point.

Is that a correct understanding?

Jerry Reed
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That is correct.  I don't know what the white in the Macbeth Color checker is supposed to read when "correctly exposed" but I would light a scene so as to provide the full dynamic range that the camera can capture, and then adjust for printing in my final version of the image.

I don't remember what the black and white values are in the electronic version of the GTM Color Checker file.  I'll check it out myself, later today.
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