Employers in California will have to post salaries for job listings under a new law signed by Gov. Gavin Newsom Tuesday.

The law takes effect on Jan. 1.

“This is a big moment for California workers, especially women and people of color who have long been impacted by systemic inequities that have left them earning far less than their colleagues,” said state Sen. Monique Limón, a Santa Barbara Democrat, in a statement to USA TODAY.

Limón says the new law will help narrow the wage gap by requiring California employers with 15 or more employees to disclose salary ranges for all job postings.

Women and people of color are more willing to negotiate and are more successful in those negotiations when salary ranges are disclosed, according to research from the National Women’s Law Center.

One of the law's supporters is Newsom’s wife, First Partner Jennifer Siebel Newsom.

“By requiring California employers to collect more substantial pay data we will continue to create more opportunity for women and people of color who are disproportionately underpaid, overworked, and barred from professional and economic opportunity,” she said in a statement.

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The new California law imposes penalties on employers for failing to report pay scales data to the state.

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"Transparency is key, but so is accountability," said Joanna Kim-Brunetti, chief legal officer and EVP of regulatory affairs for Trusaic, a workplace equity software provider. "This penalty provision will ensure compliance and, with that, accountability."

Equal Rights Advocates praised the new law as a "blueprint for other states to follow."

"We are thrilled to see that continued public awareness about the need for pay transparency has led to this bill becoming law," said Jessica Ramey Stender, policy director and deputy legal director.