# Implementing tone mapping on reference displays Detect reference displays and keep your content within the capabilities of the display hardware. ## Discussion Reference displays are calibrated to produce accurate brightness and color values within a specified range, which you use in a controlled environment to create optimized video content. Always establish if you’re using a reference display before you process any data so you can avoid system tone mapping and clamp pixel values to the range the display can accurately produce. To determine if you’re using a reference display, read the screen’s property. If the display is a reference display, the value of this property is a nonzero value that represents the largest possible pixel value the display can reproduce without clamping or tone mapping. This value may be less than . To guarantee the reference display presents your content accurately, perform your own tone mapping in a linear color space and keep pixel values between `0.0` and the reference maximum. For more information, see [Performing your own tone mapping](/documentation/Metal/performing-your-own-tone-mapping). --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)