I decided to attempt a butterfly illustration on an iPad, and it was great. As someone who prefers to hold a book in my hand rather than a Kindle, I went in thinking I wouldn't like it, but off the bat I was pleasantly surprised by the experience. One especially nice thing about coloring in an app versus on paper: being able to erase it and start all over again if you really like one pattern, or if you totally botched your first go.Unfortunately though, as time went on and I lost myself in a colorful mandala (another pattern option in the app), I began to miss my old tools of the trade. I missed my color pencils, and being able to press hard and soft for the right shade rather than adjust it digitally (you can do this with the iPad Pro's Pencil , though, which does much more closely resemble the real thing).On the tablet, all of the fancy features started to take away from the psychological benefits that I had experienced with my physical coloring books. The concept is great, and the app is executed wonderfully, but there was something missing — it just wasn't quite as satisfying.For me, coloring is more than just putting ink inside the lines. I lost things like the calming effect of spreading out my pens and pencils on the table. Nostalgia, ritual, and habit are powerful emotional stimuli, and I couldn't get that out of an app.