I was playing with the trace feature in Inkscape to convert a black-and-white photo to a grayscale vector image, and discovered something very interesting by accident when I imported the svg file to Illustrator. After making the trace I broke the new object up into paths. As far as I can tell inkscape treats these as separate objects which are stacked on top of one another. But when I imported the file into Adobe Illustrator CS2, these were treated as layers of a single object that could be switched on and off individually, like alpha channels only in different shades of gray.

My question is - is there any way to do this within Inkscape itself? (or within Illustrator alone, for that matter - is this an inkscape-only feature?) The ability to break down a complex black and white image into 8 or 9 different layers (each in a different shade of gray, with all instances of a certain shade belonging to the same layer) is way more useful in some ways than being able to break down the same image into zillions of discrete pieces that must be managed individually.

Thanks!
-Eric

I don't have time to check this right now, but since a single object cannot have different colours you will probably each shade of grey is indeed a sperate object in Inkscape already, but they are all grouped together. Check the notification region when the overall object is selected and it should confirm this. You can double-click the group to 'enter' the group and modify objects within it.

Illustrator treats every object as a sperate layer. This isn't something Inkscape does, yet.