Sert and Frank Brangwyn were later hired to paint other murals in their place. Sert would paint murals on the northern corridor, while Brangwyn would paint murals on the southern corridor. Rivera did not agree with principal Rockefeller Center architect Raymond Hood's suggestion that the mural be commissioned exclusively in grayscale colors. Rivera also declined to take part in an artistic competition prior to the announcement of his commission, and he wanted to withdraw from the project when it was announced that neither Matisse nor Picasso would be painting at the RCA Building. He eventually acquiesced after Nelson convinced Hood to remove his grayscale requirement and allowed Rivera to paint Man at the Crossroads in a fresco format. However, Rivera withdrew again after Sert and Brangwyn were announced as the new artists, calling them "two inferior painters". He eventually rejoined the project by fall 1932. As part of the contract, Rivera would be paid $21,000 for the work. This was considerably more than the $10,000 he had been paid for Detroit Industry, which he continued painting even as he was negotiating for Man at the Crossroads. According to Daniel Okrent, Rivera did not read the fine print of the contract that he signed, which stipulated that in exchange for the $21,000, Rockefeller Center Inc. would hold full ownership of Man at the Crossroads; this would lead to a controversy when the work was later removed from the RCA Building. Rivera showed Abby the sketch of his proposed work in November 1932. Nelson and John also looked at the sketch, and Nelson concluded that there was nothing controversial about the planned mural. Rivera and the Rockefellers signed a contract in which they agreed that the sketch was the final plan for the mural, and that the completed work could not be different from what was on that sketch. In March 1933, Rivera traveled from Detroit to New York so he could work on the RCA Building mural. He employed artists from around the world in his six-person crew, which also included the artists Ben Shahn and Lucienne Bloch. Rivera's assistants converted his small sketch to full-size pieces of tracing paper, which would then be painted onto the wall. Also in March 1933, Webster B. Todd, one of the contractors working on the construction of Rockefeller Center, requested sketches of Man at the Crossroads because he was concerned about the mural's potential