Halo is definitely part of the effect... Poppin Pastels is one of my favorite techniques... I LOOOOOOOOOOVE IT!! And I agree with the others that the eraser works well when you want to diminish the halo and the Sponge Daubers Rock ... I only use the daubers and leave the applicators for smaller sections or detail.
Here's my sample... all done with chalks... this went on the display boards at Convention last year.. I was SOOOOO EXCITED!!! It had pictures in it.
Gallery at Splitcoaststampers