Jennifer Taylor for the Boston Globe

The Institute of Contemporary Art commissioned a 5,000-square-foot seascape by Matthew Ritchie to replace the Os Gemeos mural at Dewey Square.

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Danilo Dasilva and Don Mateucci applied a white base coat over the controversial mural last Wednesday.

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Artists Steve Brettler (left) and Liam McAlpin painted Ritchie's seascape.

David L. Ryan/Globe Staff

The Rose Kennedy Greenway Conservancy said it wants the space "to be destination for contemporary public art."

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The mural draws inspiration from Boston's history and waterfront location.

David L. Ryan/Globe Staff

Work continued on Thursday as artist Lorraine Lamb painted a line.

David L. Ryan/Globe Staff

The conservancy will fund the $17,000 production costs of the new installation.

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Ritchie's mural will remain up for as long as 18 months.

David L. Ryan/Globe Staff

Ritchie was at the site Friday and discussed his work.

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He and another artist, Tricia O'Neill, painted the final block.

David L. Ryan/Globe Staff

The collaboration is part of a residency for Ritchie that will include a multimedia performance with members of the rock bands The Breeders and The National.

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"It's been cool for us to be part of the conversation about public art, about how you can do it in kind of an outdoor forum," Charlie McCabe, director of public programs for the conservancy, said earlier this year.