Cherubini opera restored after 200 years
The original ending has been restored to a 216-year-old opera after the manuscript was put through one of the world's most advanced X-ray machines.
Italian composer Luigi Cherubini wrote Medee in 1797 - but blacked out the final aria on the original score.
Beethoven was said to have regarded Cherubini as his greatest contemporary.
Now scientists from the University of Manchester and Stanford University have used X-ray equipment to "see" under the blacked-out part to the notes below.
According to the researchers, Cherubini may have blacked out the final lines after critics complained that the opera was too long.
The opera was composed using an ink containing traces of iron, but the last page was smudged out using a different substance containing no traces of metal.
That meant equipment at the Stanford Linear Accelerator Center in the US could "see" through the top layer to the original markings below.
The team included Dr Roy Wogelius, a geochemist from The University of Manchester who normally uses such equipment to examine 150 million-year-old fossils.
"We talk about unlocking the secrets of chemical ghosts. That's what we do with fossils and this is the same thing. This is the ghost of Cherubini - we have resurrected his pen strokes," he told BBC News.
"It resurrects the score absolutely brilliantly - you can see everything. You can see the text, the notation for the different instruments and the lyrics that are written in."
The composer covered up the final section with a cheap black substance that "might have been something he was using to polish his shoes", Dr Wogelius said.
"Using visible light, we can't see through it," he said. "It's exactly as if somebody took shoe polish to a newspaper. You can't see anything.
"But because it's a different type of ink, it has different metals in it. We use X-rays to excite the metals in the ink so the inks produce their own light, and we map the light that the inks produce.
"So the carbon black disappears and we only see the trace metals - the zinc, iron and potassium pop out. You can see the composer's ink beautifully underneath the carbon black. It was one of the most rewarding and amazing scans we've ever done."
Between 1817 and 1823, Beethoven repeatedly called Cherubini the greatest living composer and Brahms considered Medee the epitome of dramatic music.