The traditional animation workflow can be implemented by Toonz Harlequin and it allows you to manage a production by following a straightforward pipeline.

Paperless Drawing: some drawings and animation elements are drawn directly in Toonz Harlequin.
Scanning: paper animation levels are scanned, processed and autocented.
Color Model: a drawing made in Toonz, a scanned image processed in Toonz, or an image coming from a 3rd party software is stored as color model.
Ink&Painting: all animation levels, both paperless and scanned ones, are painted, by using as reference a color model.
Compositing: all painted levels and images are loaded in the xsheet to create a scene; images, animations and clips from 3rd party software can be loaded as well; camera work, objects animations and special FX can be added.
Render Farm: composited scenes are rendered out by using the Toonz render farm, in the format and resolution you prefer.