I have only experimented very briefly with this App – its rivals are Procreate – with forthcoming improvements to the waterbrush system, Adobe Sketch and ArtRage, all of which have interesting watercolour effects. See Digital Watercolour.
Dedicated App for watercolour painting.
The Auryn Ink website: http://www.auryn.ink has images of art gallery-size paintings as well as manual, tutorials and FAQ.
The whole experience is rather more random than real watercolour happy accidents. But some really beautiful effects can be achieved, including layering and erasing that cannot be achieved on paper.
Canvas: There is a choice of low, high and superhigh resolution. Rough or smooth papers with different textures that affect their ways of interacting with paint. It is also possible to control run and splatter.
Stylus: Apple Pencil uses tilt and velocity for size. For quick washes the Sensui brush stylus is good. Fingers also work well.
Layers: There are 3 layers: wet, dry and fixed layers in one image that simulate the way watercolour layers and paper interact. It is possible to control evaporation, dry and fix layers to build up images.
An image layer can be inserted at the bottom for reference/deletion.
No blend modes.
Undo: is on a timer and has to be done before layer dries. Otherwise use eraser and paint over.
Brushes: four types of tip to combine with a range of ‘footprints’ and a variable eraser to get mask effects. There is a paint flow and size control. Using the Apple pencil size is also affected by tilt and velocity.
Colour: There is a central colour picker dialogue, with customisable palette for each painting. Holding down the brush brings up an eyedropper. Then as you paint you control interaction between water and pigment on the brush for transparency.
Output: as PNG only to iPhoto. Can send into the website to enlarge to large A1+ art gallery prints.
Text: No. They recommend theTypedrawing app.
Social network: Link to Auryn Ink website and Auryn Ink Facebook page.