How to turn off backlight on iphone 4
There is no separate "back light" setting like there used to be on some earlier phones.
In the Settings app of your iPhone, there is a section called "Display & Brightness". You can use that to make your phone's display brighter or dimmer, but as you have probably discovered, it dims or brightens both the foreground and the background elements together as one.
You can turn it all the way down, which is very dim and hard to see in normal indoor light conditions, but may be preferable in extreme low light conditions like in a nightclub setting, or in complete darkness.
Why isn't there a separate back light setting?
To fully answer this, I would probably have get into more than you ever wanted to know about displays.
First, there is really no background or foreground on today's smart phone displays. The foreground elements and background elements we see on the iPhone are really a graphic illusion created by lighting individual pixels with different colors. All of these pixels are on the same plane, so nothing is really behind or in front of anything else. It's just artistically drawn to look that way.
Brightness is simply an "intensity" setting applied uniformly across all of the underlying individual pixels within the display matrix, and has no relationship to color. For clarity, let's look at the difference between lightness in colors, versus display brightness:
COLOR LIGHTNESS is a matter of how much WHITE (all the RGB colors summed, for example) is present in a given color. This has nothing to do with display brightness.
DISPLAY BRIGHTNESS is a matter of how much LIGHT INTENSITY is applied uniformly across all pixels in the display matrix.
At zero display brightness, you would not see white any better than black, blue, green, red or any other color. You wouldn't see anything.
Why did you expect to be able to control the back light?
Prior to the smartphone era, the displays on early cell phones and pagers (and lots of other devices that had displays) had a lighted background that contrasted with dark foreground elements.
The background intensity was a separate setting on those devices, but that's because the background was the only thing that had intensity. The foreground elements were solid black LCD (liquid crystal display) segments that were used to form characters and very simple graphics and lines.
Everything we see on today's smartphone displays is dynamically drawn by lighting different pixels with different colors at different times. Individual pixels on a Retina display are nearly microscopic in size--they cannot be separately discerned by the eye.
Imagine a matrix of microscopic light bulbs, each of which can separately change to any of millions of colors and levels of brightness at any time, on command. Just imagine the sheer number and complexity of possible commands to control a Retina display!
Even if Apple wanted to provide a new feature that enabled us to separately control the perceived "back light", it would only be an illusion as well.
Such a feature would require some sort of complex algorithm to determine which pixels are involved in what you perceive as the "foreground" elements at any given time, so it could add intensity only to those pixels considered to be "background" at any given time.
Since "foreground" and "background" elements drastically change shape (and location) at any time, such a feature would be pretty daunting to implement.
You might be better off using a pure black graphic as your background image if your goal is to have more contrast to make the app icons stand out.
Aug 12, 2014 |
Apple iPhone4 4G iPhone 4