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Author Topic: One color channel blown  (Read 1437 times)

zombywoof

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One color channel blown
« on: August 15, 2011, 09:51:32 PM »

I am wondering about the practical consequences of having one color channel blown out (say in a photo with the frame mostly filled with a red subject, with the red channel blown in the brightest areas) - is this always to be avoided (by reducing exposure?), or is it sometimes OK (as there are still 256*256=~65K color values available for those pixels), or ?? - can any generalizations be made?

Thanks.


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AlanPezzulich

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Re: One color channel blown
« Reply #1 on: August 16, 2011, 07:44:32 PM »

If one of the channels is blown the data in that channel cannot be recovered. Any software or Photoshop techniques used to recover the blown data will only fill in the lost date with something which may look acceptable at best.
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digitaldog

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Re: One color channel blown
« Reply #2 on: August 16, 2011, 08:51:47 PM »

I’d strive NOT to clip a single channel with proper exposure.
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Andrew Rodney
Author “Color Management for Photographers”
http://digitaldog.net/

bjanes

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Re: One color channel blown
« Reply #3 on: August 16, 2011, 09:51:28 PM »

I am wondering about the practical consequences of having one color channel blown out (say in a photo with the frame mostly filled with a red subject, with the red channel blown in the brightest areas) - is this always to be avoided (by reducing exposure?), or is it sometimes OK (as there are still 256*256=~65K color values available for those pixels), or ?? - can any generalizations be made?

If the red raw channel is blown, data will be lost. However, if the red channel is blown in the rendered image, it may still be intact in the raw channel because of the white balance multiplier. For example, with the Nikon D7000 and exposure with daylight (CIE-D50), the red channel is multiplied by a factor of 2.11 as shown in the DXO data base for this camera (click on the color response tab). In this case, recovery can be successful with no data loss.

Regards,

Bill
« Last Edit: August 16, 2011, 09:54:19 PM by bjanes »
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