!!To be done. I used the earlier version (see image), but not explored full recent options.
SketchBook (Autodesk) is one of the earliest iPad Aps, but has been kept up to date. From available images on he web it is obvious it can produce very professional illustrations. It combines raster and vector features with:
a wide range of digital pencils, pens, markers, and airbrushes and ability to pin toolbars to the screen for easy access.
text in all installed fonts that can be manipulated and distorted.
basic rectangles, circles and vector line with variety of mirror functions
Paper 53 is good for quick sketches for a selection of virtual journals, with pages to thumb through for easy viewing. It has a very limited number of fixed setting brushes: watercolour brush, calligraphy pen, pencil, marker, ballpoint pen, eraser, paint roller, scissors, and a ruler. But these are enough to do interesting sketches with a distinctive style. It has a really useful and accessible mixer palette to enable the focus to be on colour gradation rather than getting too bound up with brush styles.
You can import or take pictures, and mark them up with text or drawings. Upload to FiftyThree’s creative community Mix.
The recent version has diagramming and note-taking tools in addition to the standard creative tool suite it has always had.