Peter Putman - Current Issues in Display Technology - February 2007

With the recognition that cathode-ray displays are rapidly disappearing, the DC Section met again in the auditorium of the National Geographic Society for a primer on video displays and a look at some current alternatives for professional reference monitoring. Guest speaker Peter Putman (ROAM Consulting) provided an excellent technical presentation on the relative merits of various monitor technologies (CRT, LCD, plasma, etc.). The lecture included descriptions of the internal workings, comparisons of strengths and weaknesses in areas such as black level and colorimetry, and many of Peter’s own measurements from monitors in his lab. Also discussed were test signals, their proper use to evaluate displays, and suggestions for test material.

Available for observation were several displays, all being fed from a Sony HDCam-SR deck, with HD and SD outputs, via Evertz distribution equipment. National Geographic kindly provided the VTR and their (now unattainable) Sony 32" HD CRT monitor. Also on hand were 23" and 24" LCD displays from Panasonic, TV Logic and Cinetal. Many thanks to these manufacturers for the generous loans of equipment and assistance from their personnel.

In the end it was apparent that alternative technologies are making great strides in meeting the visual standard set by CRTs and overcoming their own inherent weaknesses.

Advances such as pulsed LED backlights, new gas formulations and improved processing circuitry are making these displays viable as reference monitors--though scaling and de-interlacing will continue be potential issues until all production is progressive HD. One notable insight, at least to this observer, was the fact that CRTs do not have sufficient bandwidth to display 1080i HD without some detail loss. In this regard LCDs have an advantage.

Many thanks to the National Geographic Digital Media Group for their continued support of SMPTE programs and to Bob Bush at Evertz for providing refreshments.

Eric Wenocur, Section Manager and Program Chair

 

Peter Putman discusses test signals for display evaluation