Black photo after conversion to LAB-mode

Scott Kelby suggests a method of sharpening where conversion into LAB-mode is necessary. Whatever the original mode (CR2, RGB, TIFF or PSD) the photo turns completely black. The L, a and b channels are there (though every one is black) and the info palet shows the L, a and b values in the photo. There is light underneath the black.
Anyone?

I use LAB colour a lot, and don't have the issue that you mention (in fact, it works like a charm).

At what point does it go black? What profile is the image tagged with?

Usually I'd set the mode to 16 bit - colour to LAB - click on channels - click on "L" - and then use a USM.

Yes, that's what should happen, as it always used to.
But now it's all blackness I see immediately after the conversion.
It doesn't matter from what mode I convert, whether it's CR2, TIFF, jpg or PSD.
The color profile is Adobe98.

Not been a software update (that has broken it), has there?

Worth a google (with the software name)?

The problem is solved though I don't know how.
It had something to do with "color range".

Quote:

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Originally Posted by swdick

The problem is solved though I don't know how.
It had something to do with "color range".

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Strange one - oh well, at least you got it sorted :)