Then, last June, the renovation team discovered Ketra, an LED lighting startup from Austin that promised some pretty big things. ... The first was what Ketra calls “natural light”: white light sources that imperceptibly change their color and intensity throughout the day to mimic the lighting conditions outside. The second was an extreme degree of control. Ketra lights could be wirelessly grouped into zones of any number of lights that could all be separately adjusted via custom software on a wall panel, computer, or phone. The third was precision. Each Ketra bulb contained a patented sensor that measured its own color 360 times a minute to make sure the light being produced was the light being requested. Ketra was selling precisely measured, nature-approximating light, accessible throughout the massive office at the press of a button. ... who really needs them? Being all things to all people doesn’t come cheap. A single Ketra bulb costs about $100. ... before you can sell millions of dollars of high-tech lighting to some of the world’s biggest companies, you have to convince them that there is a very big problem with their light. ... At the heart of Ketra’s tech is an LED chip capable of temperature-optical feedback, which senses heat and color output in real time and adjusts itself according to that data.