Archived posting to the Leica Users Group, 2005/07/20
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Tom Thanks for the in depth discourse. Very helpful. When I was active in film visual effects, we used the Kodak Cineon system for compositing. They provided Sony Trinitron monitors which we calibrated once a week and checked every day. Basically had to run the monitors "hot" to replicate what the operator would see after the film out process. Needless to say, we went through a monitor about every 6 months. Jay -----Original Message----- From: lug-bounces+bonvini=optonline.net@leica-users.org [mailto:lug-bounces+bonvini=optonline.net@leica-users.org]On Behalf Of tlianza Sent: Wednesday, July 20, 2005 9:36 AM To: lug@leica-users.org Subject: [Leica] Some Comments on LCD technologies Hi to all, I noticed some requests for information about LCD panels and I thought that I would share some of my experience with the group. I've been designing calibration systems for displays for over 17 years and I have a great deal of direct interaction with some of the best display manufacturers and their technology. My team designed the Sony Artisan hardware as well as many other calibrators that are shipped with displays. We also designed the Eyeone Display for Gretagmacbeth. When you are looking for an LCD panel for critical image viewing, you have to expect to pay a premium for it. If you are looking at quality panels you should be aware of a few acronyms that are hints about the panel quality and usability for typical image viewing. Panels that use IPS (typically Apple, NEC-MITS high end panels), VPA (Samsung), SHA (High end sharp panels) provide excellent field of view and great stability. To the best of my knowledge, all the high end Eizo panels utilize IPS technology. A data sheet will typically list the technology as TFT/IPS or TFT/VPA. If you only see TFT, it's a good bet that you are not getting a panel that has high image quality potential. I personally use a Samsung SyncMaster 243T. This is a state of the art panel, but it cost about $1800 dollars. It is a 24 inch, VPA technology panel with a resolution of something around 1900X1200 pixels. If you go to the Dell website and search for 24 inch panels you will find this one and a cheaper one. The cheaper one has a higher luminance and actually has a faster response time. The point is that it is a standard TFT panel and it's angular field of view, while large, changes rather dramatically, making it useless for image evaluation activities. That's why the luminance is higher, it is the difference between looking into a search light verses looking at a more diffuse surface. The higher quality panels have longer response times, meaning that they are not really well suited to viewing movies or gaming. This response time is result of the switching mechanisms in the panel. That is a fundamental tradeoff in the industry today, fast response and high on-axis luminance vs a wide field of view and good tone reproduction. The higher luminance of the LCD can be problematic. My LCD luminance is a factor of three times greater than my CRT. I can't have them both on the desk at the same time. When used in dim lighting, it can be quite tiring. For this reason, if you are planning to switch to one of these newer LCD's you will have to pay a bit more attention to your surround environment, if you are doing critical color evaluation. This has been the biggest problem in my workspace. The large surface of the panel is good when working in photoshop because I set the surround to a neutral on the panel (Full screen display). I have not found color gamut to be a problem. As a color scientist, I'm well aware of the issue and in my imaging workflow, it's not a problem. If you are working in Graphic Arts reproduction activities, it may be a problem. The high absolute luminance causes an observer to see the scene as more saturated and slightly more contrasty than at lower luminance. The tone reproduction of these modern displays is quite good. The higher end displays have much better control of the driving circuits and the display transfer functions are very close to gamma - law relationships. Cheaper displays tend to have saturation issues in both the highlights and the shadows. I designed a rather critical digital test target for displays and I can say that in both shadow and highlight, the high end LCD displays often perform FAR better than any CRT monitor that I have used. I have a Sony Artisan and it is now sitting in storage. Once I started using this Samsung flat panel, the rest of the image quality issues such as noise, flicker and sharpness just overwhelmed any small contrast ratio issues the monitor might have . The fact is that this panel has a 500:1 contrast ratio which requires no tedious bias adjustment. I have to make a note about calibration. Calibration of the low end TFT panels is very tough. You can't really correct for many panel defects through calibration. When I calibrate the panel on my PowerBook 15", it corrects the highlight saturation , shadow clipping, and generates the correct white point, but at the expense of display luminance and I'm still faced with a display that has limited viewing angle. If you are a Leica user you should take the time to test some high end LCD displays from companies like Eizo, Sony, NEC, Mits, Samsung and Lacie. I would avoid the 19inch formats because there is a lot of cheap technology in expensive cases... Stick to 20 inches and above and look closely at those specs. Bring a cd with some images to a store and view the images. Unfortunately, you are not going to see many of the high end displays at Best buy or Circuit City. You will see them at PMA and CES and other tradeshows. Take care and take good pictures ! Tom Lianza Director of Display and Capture Technologies GretagMacbeth LLC 3 Industrial Drive Unit 7&8 Windham, NH 03087 603.681.0315 x232 Tel 603.681.0316 Fax _______________________________________________ Leica Users Group. See http://leica-users.org/mailman/listinfo/lug for more information