My initial rough was to sum up and force in the elements that needed to be there per the script and Bobby's request: All 4 turtles looking a bit baffled, a blend of current and future architecture, mutants milling about the streets, and some kind of billboard or jumbotron of future Shredder. This was a rough sketch done at a friend's house on scrap paper as I tried to describe to the friend how I was going to fit everything in. On a tall-format cover like this, showing the vertical trust of the buildings is easy, but fitting 4 turtles across the width and still having space to show that the crowd isn't human, was the trick.
Once I knew roughly the layout, I needed I started redrawing elements from the original sketch to tighten it up to show Bobby and in turn he could show to Nickelodeon. I drew each of the turtles separately in my sketchbook as well as drawing the background on another sheet of paper. This way I could carefully position & resize each turtle, taking advantage of the negative spaces between their shoulders, pointed arms, etc. to fit in all the info needed for the 4 to be shown while still having enough room to get my foreground and background mutants in there.
As you may notice, the jumbotron Shredder ended up being a photographed model I made. Instead of any of the billboards or the main jumbotron being fixed to anything, I opted for them all to be free-floating techno-marvels. For the round one (the point of focus), I thought the perspective of not only a circular screen and tech, but also the shredder image mapped on to it would be easier to do with a model. The shredder drawing was scanned, had a grid applied, and then I rolled it up and glued a ticker-tape ring ("MUTANTS SERVE THE LEADER") to it and a spoke & hover-engine design to it.
The above digital composite was printed out and taped to the back of a sheet of Strathmore 300 series bristol. On top of a lightbox, I inked the image onto the surface of the Strathmore bristol using the printed image I could see through it as a guide. I didn't have the perspective correct for the background in my rough, so I made a correction before committing to ink (though the center area of the furved building to the right still has incorrect vanishing points. The inks were done with Copic Multiliners (the 0.7 & 0.3 nibs mainly).
(As a side note, many of the mutants represent something, characters from other talking animal books, old TMNT RPG characters, and the cat that represented me from my old project Cats Trio.)
The inks were then scanned and I started the coloring process where you establish all the various areas as flat colors with no rendering (and often times not the final colors themselves). After I flatted in the colors on the turtles themselves, I tried to keep the other elements simple, making a 3 tone variation for the buildings and the mutants. Bobby said Nickelodeon was nervous that the turtles might get overshadowed by the foreground characters, so while these were not exactly the final color choices, I did keep in mind that I wanted the turtles to be the most vibrant of the citizens and the others should be kept more muted.
Here is another look at the final cover art with the rendering and the special effects for lighting added.
Other TMNT in Time Cover Process Posts:
It's been a fun run on TMNT. While I don't have anything else lined up with IDW currently, I do hope to come back and do some more with the TMNT sooner than later.
San Diego Comic Con: July 23-27
Boston Comic Con: August 8-10
Baltimore Comic Con: Sept. 5-7
NY Comic Con: Oct. 9-12