Home Products Download Order Contacts


Subject: Re: Exposure to the right and tone placement

Of course, if the histogram shows clipping, the raw data will also have

Depends on which histogram were talking about.


You raise a very important point about histograms that I did not consider in my post.

In his seminal article on ETTR, Michael Reichman did not elaborate in any detail on his methods of placing the highlight, but he did mention "watch the histogram".

Here is an image where the red channel is blown in aRGB:

With ProPhotoRGB it can be brought into gamut:

Here is the Luminance Histogram of the same image rendered into aRGB

And here is the same aRGB image with the Photoshop RGB composite histogram:

If camera makers show only one histogram, it should be similar to the PS RGB histogram which will show clipping in any of the color channels. The luminance histogram may not show clipping and can result in blown channels with ETTR but this is what cameras usually show.

Now I presume if my camera had shown RGB channels being rendered into aRGB space set on the camera, it would have shown a blown red channel similar to to the red color channel in PS. Had I based the exposure on this histogram, I would have reduced it to bring the red channel into aRGB gamut, which is not in keeping with ETTR, at least if you are using ProPhotoRGB.

I wonder how the experts such as Bruce and Jeff would approach this problem.


View All Messages in adobe.photoshop.camera.raw

Exposure to the right and tone placement =>


Copyright 2006 WatermarkFactory.com. All Rights Reserved.