I am trying make an image like the one on this page:
http://www2.algonquincollege.com/lp/hor ... effect.org

I don't know the words to describe that transclucent layer. How can I get that grey mostly transclucent layer? I have tried playing with opacity but I can't get anything from the picture to be visible *through* the second layer.

Sorry -- I don't know the lingo to ask my question. I hope the picture makes clear what I'm describing in my question.

Thank you...

Welcome to InkscapeForum!

Do you mean where the text is? You could reproduce that effect, probably, using a white object with partial transparency. The amount of transparency needed will depend a lot on what's underneath. Start with an A (alpha) value of 125 (which is approx 50%) and then adjust up or down as needed, with the slider. This will be found in Object menu > Fill and Stroke > Fill tab.

Let us know how it goes