Math > Log Problem?

[mezeitibi]

I tried to use the Process > Math > Log functions on the sample image "TEM_filter_sample.gif" in both ImageJ and Scion Image but the result is different!
What could be the problem? The image in ImageJ seems to be much lighter after the processing than it looks in Scion Image where it is darker.
How can the same procedure give different results in different softwares?
Thanks.

[Wayne Rasband]

> I tried to use the Process > Math > Log functions on the
> sample image "TEM_filter_sample.gif" in both ImageJ and
> Scion Image but the result is different!
> What could be the problem? The image in ImageJ seems to
> be much lighter after the processing than it looks in Scion
> Image where it is darker. How can the same procedure give
> different results in different softwares?

NIH Image and Scion Image display display 0 pixels as white and 255  
pixels as black. You can get ImageJ to behave the same way by  
inverting the image (Edit>Invert) and using an inverting lookup table  
(Image>Lookup Tables>Invert LUT). Or use the Process>Math>Exp command  
added in ImageJ 1.35q.

-wayne

[mezeitibi]

Thanks a lot, it did help.