It can happen to you on the Samsung Galaxy S7 that everything will be displayed in gray color and no longer in color. The cause is very likely that you will have enabled the Grayscale mode on the Samsung Galaxy S7.
We explain how on your Samsung Galaxy S7 the grayscale mode can be deactivated again, so you see everything in color. Navigate from the home screen to the app menu and then click the settings entry.
From here, continue on "Accessibility" and "Vision".In the following sub-menu of your Samsung Galaxy S7 now at the end of the list the entry "Grayscale" is available. Here the controller must be set to "inactive".
If done, then all the apps and menu structures are displayed again as usual in color on your smartphone display.
You now know how to turn off on the Samsung Galaxy S7 in the Android settings the Grayscale mode.
PS.: An activated grayscale mode increases battery endurance.