If you have an iPhone 4s and you feel that the image on the screen has a yellow tint, you are right. It seems that some 4S devices encounter this problem (I guess it has something to do with the glue that was used to stick the digitizer to the display). There are two ways to repair this problem. First way to repair the yellow tint is to send the phone to Apple (if you still have warranty for it). If they will acknowledge that there is a problem with your screen, they will give you another phone. This is the easy method.
The second method to repair your iPhone 4S yellow tint is to use a special app that controls the colors of the display. If you know about Apple’s iOS, you know that there is no official app like this in Apple store, and you have to look somewhere else, in the Cydia Store. In order to access Cydia Store you need to have a Jailbroken iPhone. The app is called Color Profiles. After you install it, use these settings:
- color temperature: 50%
- Profile: Bold at 50%
After these settings, the yellow tint is gone and 4S has the same tint as iPhone 4 or iPhone 5.