Barrel Distortion Correction Tutorial

This tutorial shows how barrel distortion can be removed from a photograph of an artwork prior to its submission to DeviantArt using the free photo-editing program GIMP 2.8.14.

This is one of a series of tutorials that I have recently submitted.  Here are the others:
                            Minimising Graphite Shine
                            Perspective Distortion Correction                 
                            Histogram Adjustment

These tutorials update my earlier  Tutorial in which I used a less versatile free photo-editing program and mentioned GIMP only in an update in the description below the tutorial.  I hope that these new ones will clarify the methods that I use.