Google Pixel 4 white balance fix has us seeing red at last

What you need to know

• A camera glitch in the Pixel 4 caused white balance miscalculations.
• Red colors were especially off-balance, and a red-lit room would develop as yellow.
• Google quietly issued a fix with the last software update.

The Google Pixel 4 uses computational photography to understand the scene and create a better image, but that seems to have gone awry with a glitch that caused the camera to improperly develop photos containing strong red colors. The issue was spotted over at Android Police, where reviewer Ryne Hager noticed a photo sample in which a deeply red curtain had been washed to light pink. A reader soon sent samples showing a room lit only by a red bulb, which appeared to be entirely cast in yellow when shot by the Google Pixel 4.

The problem seems to have been caused by the computational algorithms Google uses to process photographs. Instead of relying on pure sensor data to determine white balance, Google uses machine learning to compare the image against assumptions about how the image should appear.

Source: u/nalrodriguez via RedditA picture from the Pixel 4 (left, pre-white balance fix) vs the iPhone X (right)

When those assumptions are incorrect, the image looks wrong. Android Police points out that this white balance glitch also shows up in the Google Pixel 3 camera, but only when the Night Sight mode is turned on.

Night Sight was the original mind-blowing computational feature on Google's cameras that took low-light photography to a new level using computation instead of optical tricks. Google had said the new Pixel 4 uses techniques similar to Night Sight in normal shooting modes on the Pixel 4.

If this is a problem with the machine learning engine, it begs the question — what did the machine learn that caused it to misfire so strongly? Further reader-submitted samples on AP show that the glitch was fixed with the November security update.