India, Nov. 1 -- a wall turns into a cinema screen at the press of a button and a 100-inch picture suddenly looks affordable. Then you open a shopping page and find a dozen 4K smart projectors at wildly different prices, all promising a similar experience. So what are you actually paying for and will it work in an ordinary Indian living room with curtains that never fully block the sun? Here in this article, we'll walk you through the specs that decide picture quality, the smart features worth having and the practical limits nobody mentions in the listing.

This is the first trap. A native 4K projector uses a panel with a full 3840 by 2160 pixels, which is the genuine article. Many cheaper models instead use a Full HD panel and shift it r...