Hi Friends,
Well, this is probably another case of me not using a feature correctly. But at the moment, the Duplicate seems not to be working right. Here's a simple, sample image.

On the left is the original circle. On the right is the same circle which I duplicated, and colored the duplicate circle white. There are no strokes on either circle. They're both 100% opacity and 0% blur.

What's wrong with this picture, lol But seriously, I thought using Duplicate created exactly identical objects. Yet it appears this duplicate is slightly smaller than the original. This may be a similar problem to another topic I've posted (viewtopic.php?f=5&t=1067)

Thanks for your help

This actually has to do with Inkscape's renderer. It anti-aliases objects by a small amount. What that means in this case is that when the white circle is anti-aliased (ie, the edges are made fuzzy just a bit), you can see the blue circle just a bit. There's not much you can do within Inkscape to prevent it, other than make the white circle a bit bigger to compensate. I'm not sure if any of the other SVG renderers do better, either.

Thanks kelan.
So the white circle is NOT smaller, it's just the anti-alias allows the blue to show through? But why doesn't the anti-aliasing cause the same effect on the dark blue circle? Or does it? Does the blue show through because it's a darker color?

yes, both circles are the same size, and both circles have the same amount of antialiasing on their edges. The antialiased edge is very thin (as you can see). What happens on that edge is the same as in the case of 2 partially transparent objects that are stacked one on top of the other.

In your case if you change the background to dark blue, and reverse the z-order (put the white circle below the blue one) you will see a thin white edge around the blue circle. So you see the blue circle isn't "stronger" than the white, it's just an illusion that you can influence by changing background color.

If you are overlapping objects that use the exact same shape, and the AA is a problem, then I suggest you use a clip instead as this will get around that problem.

Note: Group all your objects to be clipped before clipping them, otherwise a seperate clip will be created for each object which will defeat the purpose.