This wikiHow teaches you how to change the entire display on your iPhone to black and white (greyscale). You can easily switch to a black and white screen view through the accessibility settings.
Step
Step 1. Open Settings on iPhone
Open Settings by touching the icon
on the home screen.
Step 2. Touch General under Settings
It's next to the icon
in the Settings menu.
Step 3. Touch Accessibility under General
Accessibility accommodation will open in a new page.
Step 4. Touch Display Accommodations in Accessibility
This option is under the " VISION " heading.
Step 5. Touch Color Filters under Display Accommodations
Color filter options will be opened.
Step 6. Slide the Color Filters button to
Doing so will activate the color filter on your iPhone, and you can choose one of the provided filters.
Step 7. Select Grayscale
The device screen display will immediately change to black and white (greyscale).