I guarantee you that somewhere on the order of 99% of the total movie presentations that have been shown at your theater (assuming that it is a typical commercial theater in town rather than the giant screen theaters of the Houston Museum of Natural Science or Moody Gardens in Galveston) that if indeed your theater has a 4K projector system, then the ‘4K’ which you’ve been viewing was up-converted to 4K from the DCP. Note to Ruined…don’t have a stroke after realizing this.
Objectively, maybe 98 or 97%, depending upon how long your theater has had their 4K projector. So if you’re seeing a “very noticeable” difference, then thank the projector manufacturer, the projectionist and great eyesight…..not native 4K content supplied to your theater.
Like Joe, you are also mistaken about large size being the critical factor needed to fully appreciate 4K. I’ll refer to you fellow doctorial colleague Sean McCarthy, Ph.D (of Motorola [Google]) with his presentation at last April’s NAB starting at ~ the 34 min. mark of the brightcove link listed here as it relates to applied signal processing -