Posted by
Michael Schmid on
Apr 12, 2016; 5:35pm
URL: http://imagej.273.s1.nabble.com/8-bit-to-RGB-changes-data-tp5016110p5016112.html
Hi Ed,
ImageJ maps the displayed range to the full output range if you have
'Scale when converting' enabled in Edit>Options>Conversions.
So if the display range (see Image>Adjust>Brightness&Contrast) of your
8-bit image is between 0 and 60, the value 60 and everything above is
white on the screen. Then, also the RGB image will be white in these
places.
This behavior is quite handy when converting images with a color lookup
table (LUT) to RGB: What you see is what you get.
[By the way, an RGB image has 0-255 for red, green and blue, so white is
255 for all three channels. White would correspond to 255,0,0 for YUV,
but this is not a native type in ImageJ]
Michael
________________________________________________________________
On 2016-04-12 19:19, Ed Siefker 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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