Photoshop split toning

Quick answer：

Photoshop's split toning feature is a post-processing technique used in digital photography and image editing. It involves adjusting the color of the highlights and shadows in an image separately. This method is often used to create a specific mood or artistic effect, as it allows for greater control over the image's coloration. Split toning is accessible through Photoshop's 'Adjustments' menu, where users can choose from various color options for highlights and shadows, as well as adjust the intensity of the effect.