tutorial: Pencil to digital painting

Note : a tutorial wrote in a single picture, made to be published on deviant art ( my Deviant Art account : http://deevad.deviantart.com ). I do a repost here to archive it on my blog/website.

Erratum:

• update 2012-09-08 : found an error, and commited new file with an erratum speech bubble at step '7' ; about the line art. This one got a better rendering in 'multiply'. The screenshot was done too early and show 'Normal' witch is an error.
• update 2014-07 : The automagical F2 key in Krita to "save incremental" shortcut as been moved because F2 is used to rename in 90% of other software . Find the feature in File > Save Incremental version