Mr Shoa, from London, was a graffiti artist before he trained as a painter. The artist won the Royal Society of Portrait Painters in 1992 and exhibited his work at the National Portrait Gallery’s BP portrait awards the following year.
He began painting his friends but struggled to get the portraits displayed in galleries.
He said that some museums “didn’t even reply to me”.
“It was a project about race, but the project itself received a lot of racism, so it was barely shown, up until recently,” he said.
Mr Shoa said museums changed their attitudes towards his work after the death of George Floyd, the African-American man who was murdered by white police officer Derek Chauvin in Minnesota during an arrest.
Following Mr Floyd’s death, protests spread across the world as part of the Black Lives Matter movement, which campaigns for freedom, justice and equality.