(yes, I know my 'g' in "Chicago" looks like an 's' *sigh* ...I had already placed the Chica when I realized I hadn't accounted for the shape of the 'g' and I certainly wasn't going to start all over!)
I did this lo for the November Multi Pic Challenge and the November Page Maps ETC Challenge, Sketch #5 - from PageMaps, which can be found here http://www.scrapbook.com/galleries/298615/view/3781475/-1.html
I used Color Core cs for the base of this lo. I chose the black with the blue, because the pics are so dark and because it's about water...made sense to me. :)
I pierced a border around the page, piercing from the back side so that when I turned the cs over, I could light sand the pierced holes and have the blue show. I also use the Color Core for "Chicago" and for "Shedd". I cute the alphas using my Sizzlits, then sanded them carefulle. Where it I couldn't get the emery board to reach the small areas, I placed the alpha onto my cutting mat, then carefully used my craft knife to scrape away the black on the edges to reveal the blue.