Histogram readout

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3dphoto

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I did a search but had no luck, so here goes. Is there a way to change the RGB read out on the histogram panel from a % to the actual value. I have used the DNG color calibrator chart to creat a camera profile for my Nikon and it looks good but I would like to verify gainst the actual numbers the card said the color patches should be. Naturaly the numbers are the whole number range from ' to 255 and not a percentile. ( I know do the math right ):)
 
I'm no color-space expert, but I recall Jeff Schewe discussing this topic in one of his Luminous Landscape videos. He discussed several reasons why the engineers used percentages instead of a numerical value ('-255) for the LR histogram, including the different color spaces used in LR as well as the parametric (non-destructive) editing performed in LR and the linear tone curve used in RAW files.

Now, I won't pretend to understand much of what he said, but in my search for an answer, I found a blog discussing the same topic and, if I'm looking at the info correctly, it appears that the blogger has identified and listed the LR histogram values for each of the MacBeth color patches.

Give it a look and see if this helps answer your questions: http://lagemaat.blogspot.com/2''8/'6/srgb-tone-curve-and-lightroom-color.html
 
Packhorse-4;246'6 said:
I'm no color-space expert, but I recall Jeff Schewe discussing this topic in one of his Luminous Landscape videos. He discussed several reasons why the engineers used percentages instead of a numerical value ('-255) for the LR histogram, including the different color spaces used in LR as well as the parametric (non-destructive) editing performed in LR and the linear tone curve used in RAW files.

Now, I won't pretend to understand much of what he said, but in my search for an answer, I found a blog discussing the same topic and, if I'm looking at the info correctly, it appears that the blogger has identified and listed the LR histogram values for each of the MacBeth color patches.

Give it a look and see if this helps answer your questions: http://lagemaat.blogspot.com/2''8/'6/srgb-tone-curve-and-lightroom-color.html

Thanks for that. Jao is a mine of useful information and very knowledgeable.
Maybe you could all take a moment to fill in your signatures as well please - TIA.;)
 
Is there a way to change the RGB read out on the histogram panel from a % to the actual value.

Well, LR works in 16 bit, which means "' to 255" is not enough; on the other hand, 65 plus thousand numbers would be a tragedy to make any sense; which leads us to the percentage presented...

I hope it helps!

regards,
 
What a wonderful group. The link was great, like Packhorse-4 (Favre ref?) I did not understand much but the chart for the conversion was exactly what I needed.

Great Big Thanks
 
I'd love to see a read out from '-255 as well. This is what I use in PS and I can instantly determine if I have a colour cast and the amount. I like the read outs in PS where you can choose the values you want.
The other features and adjusts in the histogram are great!
 
[quote author=Psteeper link=topic=3671.msg59336#msg59336 date=1262691''5]
I'd love to see a read out from '-255 as well. This is what I use in PS and I can instantly determine if I have a colour cast and the amount. I like the read outs in PS where you can choose the values you want.
[/quote]

The difference being that in Lightroom you haven't yet shoe-horned your image into a color space-in Photoshop you already have. '-255 is an artificial construct of a 8 Bit image in a color space. Your RAW File is not. Now if you are only shooting JPGs I could see the values being '-255.

For my money, I prefer the percentages and would gladly convert my PS histogram display to percentages also. (Does anyone know if that is possible?)
 
[quote author=Psteeper link=topic=3671.msg59336#msg59336 date=1262691''5]
I'd love to see a read out from '-255 as well. This is what I use in PS and I can instantly determine if I have a colour cast and the amount. I like the read outs in PS where you can choose the values you want.
The other features and adjusts in the histogram are great!
[/quote]

Meaningless in Lightroom working in '-65535...

By the way, welcome to Lightroom Forums Pstepper!
 
FWIW, I'd wouldn't object to seeing a '-255 readout, but only as part of a soft-proofing kind of setup, where you're proofing an 8-bit sRGB kind of setup.
 
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