By Steve Tawa

PHILADELPHIA (CBS) – The Barnes Foundation will soon be displaying previously unknown works by the French master, Paul Cezanne. They were found hidden on the backs of two of his watercolors.

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Those watercolors, which depict the landscape of Cezanne’s beloved southern France, were acquired by Albert Barnes in 1921 — both of which have been a part of the permanent collection, hanging in room 20 of the Gallery.

The newly discovered unfinished pieces – one graphite and one watercolor – reveal he got a better deal than he thought.

Consulting Curator Martha Lucy of the Barnes Foundation says it’s likely no one has seen the hidden pieces for nearly a century – since before Dr. Barnes purchased them:

“We’re not sure whether Barnes knew that they were there or not. It seems pretty likely that he didn’t know, because there’s no discussion of them in his correspondence.”

(Reporter) When he acquired them, how much did he pay for them?

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“He paid $100 for each one,” Lucy says.

The hidden sketches were discovered when the original works were taken down for conservation work. Barnes Chief Conservator of Paintings Barbara Buckley says they were replacing brown paper on the backsides with acid-free paper, to preserve the pieces:

“The brown paper was a craft paper, very poor quality and acidic.”

Barbara Buckley, Barnes Chief Conservator of Paintings (Credit: Steve Tawa)

Barbara Buckley, Barnes Chief Conservator of Paintings (Credit: Steve Tawa)

The watercolors and the sketches (on the reverse side), will be on display in double-sided frames, with both sides visible, beginning April 10th for eight weeks. Then the works will be returned to their original location.

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Barnes Foundation officials say the post-Impressionist painter often worked on both sides of paper.