In a flame test, carbon produces a red-orange flame, although the exact shade depends on the temperature of the flame. A higher temperature leads to flames that are closer to yellow in color, while a lower temperature leads to darker red flames. Extremely high temperatures produce blue flames.
The amount of oxygen reaching the carbon also affects the flame color, with more oxygen leading to a cooler yellow flame. Combustion reactions, such as the one used to produce a flame in the flame test, already involve the combustion of carbon, so the color produced during a carbon flame test is very similar to the color of the flame itself.