Evernote or iA Writer fill in nicely for larger projects, but for smaller 'napkin scribbles' I prefer using the handy stylus and a few apps optimized for the quick sketch... iOS
Left: ASKetch - Right: Ink for iOSASKetch An essential app which works equally well on the big and small screen, ASKetch, on the surface is very simplistic. The app emulates the dynamic lines of a graphite pencil or charcoal in near-perfect detail. Dig deeper and you'll find features like smudging and image transformation (enlarge/shrink and rotate) that make ASKetch quite a versatile app for artistic sketches. $3 Ink for iOS If you're looking for barebones with a minimum of features (price included), Ink is right up your alley. Part of Minimal Tools pair of note taking apps, the app abides by the philosophy of 'less features, quicker loading times'. Ink for iOS is fast and takes small sketches or diagrams with ease, but note, there is no Dropbox or in-app galleries. Instead, images can only be saved to photo albums, but there is the option to share via Facebook, Twitter, or e-mail by double tapping a corner. Free Android
Left: SketchBook Mobile - Right: DoodledroidSketchBook Mobile Autodesks powerful brand of graphic apps makes itself at home on smartphones. Especially notable for the Android platform where screen sizes can go as high as 5". SketchBook Mobile has a slew of brushes, pens, colors, layers, layer effects and can go from concept to finished piece all in the palm of your hand. Or you can export your sketch to the desktop as a .psd and take it even further with software like Photoshop, Painter and more. $2 - Also available for iOS Doodledroid Doodledroid makes the convincing argument that bite-sized scribbles are better on a smartphone because of dynamic coloring. Here is an app that manages to pack a whole slew of tools that emphasize brushes and smudging to make incredible images without any of the paint stains. $1 Windows Phone
Left: Fantasia Painter - Right: Sketch BoardFantasia Painter For a powerful image editor on the Windows Phone platform, Fantasia Painter certainly packs a punch. Whether you want to start an image from scratch or modify a photo taken this app can bring your imagination to life with help from 32 brushes and over 100 effects like colorize, mold, clone stamp and more. Great for beginners and intermediates alike or anyone who need to create a visual on the fly from their smartphone. $2 Sketch Board A reliable go-to app that's ready and willing when you are is Sketch Board. I love the Metro based interface offering a look that's clean and doesn't get in the way of the creation process. You can trace over photos by importing them as a background image where you can zoom, rotate or shift it your liking and pen or paint over it for fun. Free Cover Photo: Jason Rodway - All images belong to their respective owners.