Posted by
Swayne, Theresa C. on
Apr 12, 2016; 5:34pm
URL: http://imagej.273.s1.nabble.com/8-bit-to-RGB-changes-data-tp5016110p5016111.html
Hi Ed,
The RGB conversion in ImageJ scales the output pixel values according to the display contrast. Anything above the white level (max. displayed value) will become 255.
Perhaps you adjusted the contrast, or perhaps the images were autoscaled when you opened them.
To check this: Image > Adjust > Brightness & Contrast, click Set, and set the minimum and maximum displayed value to 0 and 255 respectively. Then convert and see if you get the same issue.
Hope this helps,
Theresa
On Apr 12, 2016, at 1:19 PM, Ed Siefker <
[hidden email]<mailto:
[hidden email]>> wrote:
I have a stack of three monochrome 8-bit images that I need
to convert to RGB so that they stay the right color when I
save them as a tiff. When I hover over the brightest part of
the image, I get values in the 60s. After selecting Image->
Type->RGB Color, that area is saturated at 255.
What's going on here? When you convert a monochrome to
a three channel image, shouldn't you just preserve the data in
the monochrome and add two channels full of zeros?
-Ed
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Theresa Swayne, Ph.D.
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Herbert Irving Comprehensive Cancer Center
Columbia University Medical Center
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