Display Accommodations: iOS lets you invert colors, reduce white point, enable grayscale, or choose from a range of color filters to support different forms of color blindness or other vision challenges. You can select a common preset or fine-tune the color tint and hue to customize a display setting that works for you. With the Smart Invert Colors setting, iOS automatically recognizes when a piece of media is using a dark color style, so you can reverse the colors of the display without affecting the look of images, videos, and certain apps. And once you set your filters, the settings apply to everything that appears on your iPad or iPhone.
Turn on Invert Colors
If you benefit from viewing items against a dark background, you can use Invert Colors to change how content is displayed on your screen. Smart Invert reverses the colors on the display, except for images, media, and some apps that use dark color styles. Classic Invert reverses all colors on the display.
- Go to Settings > General > Accessibility > Display Accommodations > Invert Colors.
Turn on Color Filters
If you have color blindness or other vision challenges, you can use Color Filters to help you differentiate between colors. Color Filters can change the look of things, like pictures and movies, so you may want to use it only when needed.
You can turn on Color Filters from the Settings app.
- Go to Settings > General > Accessibility > Display Accommodations > Select Color Filters.
When you turn on Color Filters, there are four preset filters to choose from:
- Grayscale
- Red/Green for Protanopia
- Green/Red for Deuteranopia
- Blue/Yellow for Tritanopia
- To assist you, you’ll see three examples of color spaces to help you select an option that fits your needs. Swipe left or right on these examples to find a filter that works best for you.
Adjust color intensity
You can adjust the intensity of any of the Color Filters to fit your needs.
- Go to Settings > General > Accessibility > Display Accommodations and adjust the Intensity slider to customize a filter that’s more intense or less intense.
Adjust Color Tint
If you have color or light sensitivity, you can change the Color Tint of your display. This will allow you to change the hue of the entire display on your iPhone, iPad or iPod Touch.
- Launch Settings from your Home screen > Tap General > Tap Accessibility > Tap Display Accommodations > Tap Color Filters > Tap the switch next to Color Filters to turn them on > Tap Color Tint > Tap and drag the Hue slider at the bottom until the tint is what you need > Tap and drag the Intensity slider until the intensity is where you need it to be.
Source: https://www.razmobility.com/ios-built-in-accessibility/#learn-more