The basic idea came from FC0223 Lost in The Andes, a story Barks created already in 1949. It has always been regarded as one of his most inventive and technically perfect. Barks himself acknowledged that repeatedly over the years except for one technical aspect (see more HERE). The story's popularity logically resulted in Barks making two other paintings in 1973 fantasizing over the main motif, i.e. 9-73 Eight-Cornered Eggs and 13-73 Square Eggs, but a contributing reason that resulted in yet another painting was that the American artist Keno Don Hugo Rosa made a sequel to Barks' story titled AR130 Return to Plain Awful (see more HERE). The story premiered in February 1989, and it has seen been published in 52 issues covering 17 countries.
In it, the Ducks return to the Peruvian valley but this time accompanied by their uncle Scrooge. In a half-page splash similar to his own, Barks found the overall motif to use for his new painting as can be seen above. This is the only time during his duck painting years that Barks used an overall motif partly taken from another artist - and he even used the story's title as his own!

In order to get the overall motif correct in his paintings, Barks sketched small, rough parts on numerous tissues, which he could move around until he was entirely satisfied. He referred to the tissues as Feeling Around sketches. Of course, only a very few of the hundreds of tissues Barks sketched have survived for the simple reason that he had neither need nor reason to file them. Luckily, he left a few images - in different stages of completion - from the tissues he used for this painting. You are presented to some of these tissues focussing on the Duck family group. You can see some additional tissue examples focussing on a more technical aspect HERE.
When the sketches were thoroughly worked through and pencilled in, Barks placed the transparent tissues on a board and moved them around until he found the best composition. When this was done he placed carbon paper behind the tissues after which he was able to trace the lines directly to the board. Then Barks began painting.

When Barks had begun producing paintings used for limited edition lithographs he would typically solve problems with colouring and design by making small concept miniatures in about a quarter of the size of the finished products. These preliminaries were his way of perfecting the ideas before actually having to start the paintings. But for Return to Plain Awful Barks introduced yet another experimental novelty by taping a transparent sheet of acetate over a preliminary painting, which would enable him to paint over selected portions of the painting without 'damaging' them if the ideas fell through.
Above you can follow a fraction of the preliminary process via 4 quarter-sized painting sketches all in the size of 12x15" (300x380mms). First you have a relatively rough preliminary followed by the same image mounted with a sheet of acetate with details removed. Then new and thicker colours have been added, and finally the colours have been perfected and a lot of, mostly quite subtle, alterations have been added. The easiest to spot from sketch to sketch is probably the changes in the valley town.
In the painting Barks allowed himself a few additions compared to his original story: As mentioned, Scrooge was not a member of the story's initial expedition and the Junior Woodchucks (represented by the flag) were not even invented at the time. Furthermore, none of the square eggs in the story were golden ones.

The finished painting was sold in 1989 and booked in Barks' own numbering system as 136/89, i.e. his official 136th painting in the Disney duck series. The following lithographs received the number 13. The original painting size is 24x30" (610x760mms), and it is made with oil on Masonite, which was Barks' usual method.
Notice that Barks signed the painting with his name only with no references to Walt Disney. This was done by special agreement with the contractor and publisher of the lithograph and serigraph series, Another Rainbow Publishing.

The paintings Barks made in the surrounding months were sold at 22,500 dollars each, which was a clear indication that Barks 'ruled' the market and could demand any prices he chose to. Return to Plain Awful became just another example of this beneficial rule, when Barks sold it.
The amount was so huge at the time that it was customary for the purchasers to pay (in advance) in 3 installments of 7,500 dollars!

Still, the main income for this as well as other paintings produced for the lithograph market came from royalties that ran in the years to come (see more HERE).
For this painting Barks first received a royalty of 12,000 dollars as the beginning of a steady stream of fringe income, and at the same time he received 9,000 dollars for another lithograph that was never even published as a painting (see more HERE)!

The painting was made in several lithographic editions such as Regular and Gold Plate plus a few Publisher's, Printer's, and Artist's Proofs as well as Special and Foreign Editions. The sizes vary from 16x20" (400x500mms) to 18x21" (450x530mms), and they are all numbered and signed by Barks.
The selling prices varied greatly from 780 to 1450 dollars depending on the edition.