Conservators at Kelvingrove Art Gallery and Museum are a step closer to solving a 250-year-old mystery.
They have been working on an 18th Century portrait to uncover a black servant who some experts believed was deliberately painted out.
The portrait of tobacco merchant John Glassford and his family was painted in the 1760s by Archibald McLauchlan.
The wealthy Glaswegian's black servant was included in the picture as an indicator of his wealth and status.
The picture shows the Glassford Family when they were living in Shawfield Mansion, off the Trongate, on what is now Glassford Street.
For many years, it was thought the family had painted the figure out, embarassed by their connections with the slave trade.
But a senior conservator, Polly Smith, believed the figure simply faded with time and her team eventually hope to uncover the man's identity.
The Glassford family's involvement in slavery is one of many strands that Glasgow City Council is exploring in a series of exhibitions to mark the 200th anniversary of the abolition of the slave trade bill.