question: What Exactly Causes Phone Screens to Bleed Purple?
comment: Broken liquid crystals. you have an LCD or Liquid crystal display. Imagine a substance with some of the order of a solid and some of the fluidity of a liquid. What you have is a liquid crystal—a kind of halfway house in between. At any given moment, liquid crystals can be in one of several possible "substates" (phases) somewhere in a limbo-land between solid and liquid.
passages: Gizmodo editor Diaz discussed the correspondence between Apple and a reader about purple flare in pictures taken on iPhone 5 camera. Apple's response to the issue was that it is normal and advised the customer to aim the camera away from bright light sources when taking photos. Tests conducted by TechCrunch indicate that the problem existed on the iPhone 4s but was more distinct and pronounced on the iPhone 5. Consumer Reports found that the purple haze effect occurred on several other manufacturers' phones including the Samsung Galaxy S III and Motorola Droid Razr Maxx, and that it was not less pronounced on the iPhone 4s. The report concluded that digital cameras in general, including higher-end SLRs, can all suffer from lens flare in which a purple-tinted effect was not uncommon.
   The camera on the iPhone 5 reportedly shows purple haze when the light source is just out of frame, although Consumer Reports said it "is no more prone to purple hazing on photos shot into a bright light source than its predecessor or than several Android phones with fine cameras..."
  
  On all five model generations, the phone can be configured to bring up the camera app by quickly pressing the home key twice. On all iPhones running , it can also be accessed from the lock screen directly.
   A dark dot defect is usually caused by a transistor in the transparent electrode layer that is stuck "on" for TN panels or "off" for MVA/PVA and IPS panels. In that state, the transistor places the liquid crystal material in such a way that no light ever passes through to the RGB layer of the display.
  
  Section::::Variations.:Bright dot defects.
   The 15.6" Full HD "Radiance" display panel which was sold with this laptop has an issue in which the color red displays closer to orange. In response HP had issued a software utility called MyDisplay but does not appear to completely correct the problem with some users saying all it does is mask a problem which is actually hardware based and not software.
   Some users reported a yellow discoloration of the screen that disappeared after several days, which was attributed to the glass lamination glue that was used. It did not have time to dry fully before the unit reached consumers due to the speed of manufacturing. Another issue reported by some users within days of the iPhone 4 release was that during calls the proximity sensor can be insensitive, so that facial contact with the touchscreen can end calls, mute calls, and dial other numbers. Some users reported that, particularly in low-light conditions, photos taken on the iPhone 4 sometimes contained blue or green "splotches." Issues with white balance were also discovered, particularly when using the flash.
   Purple fringing is usually attributed to chromatic aberration as described above, although it is not clear that all purple fringing can be explained this way. Other attributed causes of purple fringing in digital photography include many hypothesized sensor effects:
  
  BULLET::::- Digital noise in dark areas
  
  BULLET::::- Image processing and interpolation artifacts (almost all CCDs and CMOS require considerable processing)
  
  BULLET::::- Stray ultraviolet and/or infrared light
  
  BULLET::::- Image bloom from overexposure of CCD sensor (not applied to CMOS)
  
  Section::::Mitigations.
  
  Commonly advocated methods of avoiding purple fringing include:
  
  BULLET::::- Avoid shooting with a wide-open lens in high contrast scenes.
   The Pixel 2 XL has an issue where the screen may flash randomly. It occurs when the phone is locked or unlocked. The issue was fixed in the June system software update, but returned with the July update.
  
  Section::::Issues.:Audio issues.
   BULLET::::- Sometimes, the display lights up for a few seconds and then goes out again. This happens when the phone battery depletes by one "bar", which may be seen as pointless as the lights coming on would increase drain on the battery. This was meant to be an early warning for low battery.
  
  BULLET::::- Sometimes, for no apparent reason, an image or video clip is copied.
   Color bleeding (printing)
  
  In printing and graphic arts, mixing of two dissimilar colors in two adjacent printed dots before they dry and absorb in substrate is referred to as color bleeding. Unless it is done for effect, color bleeding reduces print quality.
  
  Prior art applied this term to the phenomenon of single color ink following the fibers of the paper.
   An old name for this color, used by Robert Ridgway in his 1912 book on color nomenclature, "Color Standards and Color Nomenclature", is true purple.
  
  Section::::Computer web color purples.
  
  Section::::Computer web color purples.:Purple (HTML/CSS color) (patriarch).
  
  This purple used in HTML and CSS actually is deeper and has a more reddish hue (#800080) than the X11 color purple shown below as "purple" (X11 color) (#A020F0), which is bluer and brighter.
   Plasma displays were at one time highly susceptible to burn-in, while LCD-type displays are generally not affected. The wide variation in luminance degradation with RGB-based OLED will cause noticeable color drift over time (where one of the red-green-blue colors becomes more prominent).
   BULLET::::- Dead or stuck pixels may occur during manufacturing or after a period of use. A stuck pixel will glow with color even on an all-black screen, while a dead one will always remain black.
  
  BULLET::::- Subject to burn-in effect, although the cause differs from CRT and the effect may not be permanent, a static image can cause burn-in in a matter of hours in badly designed displays.
  
  BULLET::::- In a constant-on situation, thermalization may occur in case of bad thermal management, in which part of the screen has overheated and looks discolored compared to the rest of the screen.
   The iPhone X has a 5.8-inch OLED color-accurate screen that supports DCI-P3 wide color gamut, sRGB, and high dynamic range, and has a contrast ratio of 1,000,000:1. The Super Retina display has the True Tone technology found on the iPad Pro, which uses ambient light sensors to adapt the display's white balance to the surrounding ambient light. Although the iPhone X does not feature the same "ProMotion" technology used in the displays of the second-generation iPad Pro, where the display delivers a refresh rate of 120Hz, it does sample touch input at 120Hz. OLED screen technology has a known negative trend of "burn-in" effects, in which particular elements consistently on the screen for long periods of time leave a faint trace even after new images appear. Apple acknowledged that its OLED screens were not excluded from this issue, writing in a support document that "This is also expected behavior". Greg Joswiak, Apple's vice president of product marketing, told "Tom's Guide" that the OLED panels Apple used in the iPhone X had been engineered to avoid the "oversaturation" of colors that using OLED panels typically results in, having made color adjustments and "subpixel"-level refinements for crisp lines and round corners. For out-of-warranty servicing for damages not relating to manufacturing defects, screen repairs of iPhone X cost US$279, while other damage repairs cost US$549.
   Section::::Other STN displays.
  
  BULLET::::- DSTN can stand for:
  
  BULLET::::- Double layer STN – An earlier passive matrix LCD technology that used an extra compensating layer to provide a sharper image.
  
  BULLET::::- Dual Scan STN – An enhanced STN passive matrix LCD. The screen is divided into halves, and each half is scanned simultaneously, thereby doubling the number of lines refreshed per second and providing a sharper appearance. DSTN was widely used on earlier laptops. See STN and LCD.
  
  BULLET::::- FRSTN – Fast Response STN
   In the RGB color model, named for the colors red, green, and blue, used to create all the colors on a computer screen or television, the range of purples is created by mixing red and blue light of different intensities on a black screen. The standard HTML color purple is created by red and blue light of equal intensity, at a brightness that is halfway between full power and darkness.
   BULLET::::- Earlier generation displays were more susceptible to screen burn-in and image retention. Recent models have a pixel orbiter that moves the entire picture slower than is noticeable to the human eye, which reduces the effect of burn-in but does not prevent it.
  
  BULLET::::- Due to the bistable nature of the color and intensity generating method, some people will notice that plasma displays have a shimmering or flickering effect with a number of hues, intensities and dither patterns.
   BULLET::::- Limited viewing angle in some older or cheaper monitors, causing color, saturation, contrast and brightness to vary with user position, even within the intended viewing angle.
  
  BULLET::::- Uneven backlighting in some monitors (more common in IPS-types and older TNs), causing brightness distortion, especially toward the edges ("backlight bleed").
  
  BULLET::::- Black levels may not be as dark as required because individual liquid crystals cannot completely block all of the backlight from passing through.
   Prior to the official release, it was reported that some Galaxy S8 displays had a bad white balance, causing them to exhibit a reddish tint. Samsung stated that the Galaxy S8 was "built with an adaptive display that optimizes the colour range, saturation, and sharpness depending on the environment", but noted that the device's operating system provides settings for manually adjusting the display's appearance and white balance. On 21 April, Samsung stated that the red tinting was purely a software issue, and would be patched in a future update. "The Investor" reported that Samsung would replace the affected devices if a software update did not fix the issue. Updates in various regions started rolling out in early May, fixing the issue.
   A new "Smart Invert" feature, dubbed a "dark mode" by some publications, inverts the colors on the display, except for images, some apps, and some user interface elements. Using the iPhone X, which utilizes OLED technology, some news outlets have reported that this feature can conserve battery life by turning off pixels when black, saving energy by preventing itself from displaying a white pixel.
   Defective pixel
  
  Defective pixels are pixels on a liquid crystal display (LCD) that are not performing as expected. The ISO standard ISO 13406-2 distinguishes between three different types of defective pixels, while hardware companies tend to have further distinguishing types.
  
  Similar defects can also occur in a charge-coupled device (CCD) or CMOS image sensor in digital cameras. In these devices, defective pixels fail to "sense" light levels correctly, whereas defective pixels in LCDs fail to "reproduce" light levels correctly.
  
  Section::::Variations.
  
  Section::::Variations.:Dark dot defects.
   Using additive colors such as those on computer screens, it is possible to create a much brighter purple than with pigments where the mixing subtracts frequencies from the component primary colors. The equivalent color on a computer to the pigment color red-violet shown above would be this electric purple, i.e. the much brighter purple you can see reproduced on the screen of a computer. This color is pure purple conceived as computer artists conceive it, as the color on the color wheel halfway between color wheel violet and electric magenta. Thus, electric purple is the purest and brightest purple that it is possible to display on a computer screen. Its RGB code is (191, 0, 255).
   A bright dot defect is a group of three sub-pixels (one pixel) all of whose transistors are "off" for TN panels or stuck "on" for MVA/PVA panels. This allows all light to pass through to the RGB layer, creating a bright white pixel that is always on. This is commonly known as a "hot pixel".
  
  Section::::Variations.:Partial sub-pixel defects.
  
  A partial sub-pixel defect is a manufacturing defect in which the RGB film layer was not cut properly.
  
  Section::::Variations.:Tape automated bonding (TAB) faults.
   In many cases, the use of a screensaver is impractical. Most plasma-type display manufacturers include methods for reducing the rate of burn-in by moving the image slightly, which does not eliminate screen burn, but can soften the edges of any ghost image that does develop. Similar techniques exist for modern OLED displays. For example, manufacturers of Android Wear watches with OLED displays can request that Android Wear enable "burn protection techniques" that periodically shift the contents of the screen by a few pixels.
   The lower one is the sRGB colour #990024, intended for viewing on an output device with a gamma of 2.2 . It is a representation of RHS colour code 66A, which has been equated to "Tyrian red", a term which is often used as a synonym for Tyrian purple.
  
  Section::::Philately.
  
  The colour name "Tyrian plum" is popularly given to a British postage stamp that was prepared, but never released to the public, shortly before the death of King Edward VII in 1910.
   Section::::Screen burn-in.
  
  Image burn-in occurs on CRTs and plasma panels when the same picture is displayed for long periods. This causes the phosphors to overheat, losing some of their luminosity and producing a "shadow" image that is visible with the power off. Burn-in is especially a problem on plasma panels because they run hotter than CRTs. Early plasma televisions were plagued by burn-in, making it impossible to use video games or anything else that displayed static images.
  