strange PNG reading behavior

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strange PNG reading behavior

Roger Bourne
Hi All

I am finding that any (Photoshop) grayscale PNG image I open with ImageJ
is automatically equalized and converted to RGB.
The same image saved as TIF (in Photoshop) opens as 8 bit without
equalization.
The 8 bit TIF image saved as PNG in ImageJ reopens as RGB without
equalization.
Can I stop this happening?

Thanks
Roger
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Re: strange PNG reading behavior

Wayne Rasband
> Hi All
>
> I am finding that any (Photoshop) grayscale PNG image I open with
> ImageJ is automatically equalized and converted to RGB.
> The same image saved as TIF (in Photoshop) opens as 8 bit without
> equalization.
> The 8 bit TIF image saved as PNG in ImageJ reopens as RGB without
> equalization.
> Can I stop this happening?

What version of ImageJ are you using?  I found this by searching the
release notes (http://rsb.info.nih.gov/ij/notes.html) for "PNG":

    1.41c, 16 May 2008
         Fixed a bug that caused 8-bit PNGs to open in RGB format.

To upgrade, use the Plugins>Utilities>Update ImageJ command. Or
download the latest ij.jar (v1.41g) directly from
<http://rsb.info.nih.gov/ij/update/ij.jar>.

-wayne