A new study revealed darker-skinned Black people are more likely to go to prison than their lighter counterparts.

The report, authored by Harvard University sociologist Ellis Monk, disclosed results from a survey conducted between 2001 to 2003, according to Quartz.

The original interviewers categorized the participants based on their skin color, from very light to very dark. Monk used the data to juxtapose the people’s experience with the criminal justice system.

The researcher found Black people were 36% more likely to go to jail overall. However, when broken down by skin color, dark-skinned people were 65% more likely to be imprisoned, a 30% increase.

“Put bluntly, while being black (and poor) may already predispose one to have a higher probability of contact with the criminal justice system and harsher treatment … being perceived as blacker intensifies this contact further and may increase the harshness of one’s treatment by the [criminal justice system] as an institution,” Monk wrote.

The study shows skin tone and features must be accounted for when discussing the effects of racism.

“Racial inequality is not just a matter of belonging to this broad, homogenous category of Black,” Monk told Quartz. “But there’s subtle gradations in skin tone, ranging from very fair skin to very dark skin.”

The pitfalls of colorism continue to be well-documented.

A 2011 Villanova University study found lighter Black women received 12% less prison time.

Another Villanova University study published in 2015 found white people thought lighter-skinned Black and Hispanic people were smarter than darker people with the same education and background, according to Vox.

Another study found light-skinned Black men with bachelor's degrees have an easier time in the job market than a dark man with an MBA.