Durham NC Skyline, Durham

The other day I got an email from a National Magazine asking if I had any stock images of the Durham NC Skyline with an FPO. I replied that I only had snapshots, but Durham is only a 20 min. drive and I'd be happy to shoot some images. The next day I'm emailed a call sheet,times,names of all the editors/creative people etc. It's a fast paced world and tonights the only night I can do the photo's and the weather is perfect. I drive up to Durham and start shooting and another photographer shows up ????? We're both shooting for the same magazine except he was the one that was hired and I was just emailed the call sheet. What have I learned ???? Never shoot something without actually speaking with someone and have a written contract. I now have lots of stock photography images of the Durham NC skyline for sale.