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AVOID THESE 3D GLASSES! -- They have red+blue lenses---NOT red+cyan lenses as advertised!
on January 12, 2016
This review is for the anaglyphic clip-on glasses sold by HXYTECH. The eBay ad was titled: "3D Direct-Clip On Glasses for 3D Movies, DVDs and Games that Require Red/Cyan Lenses". I purchased two pair of these glasses for $4.79 each ($9.58 total) on 07-Jan-2016 and the order was fulfilled by Amazon with free Prime shipping.
AVOID THESE 3D GLASSES!!! The Amazon ad is false. They do not have red and cyan lenses. Instead, they have red and BLUE lenses. The Amazon ad states: "Optical quality, cast acrylic lenses tinted to EXACTING COLOR STANDARDS." (emphasis mine) Rubbish!!! These lenses are NOT tinted correctly. The blue lens has no hint of green in it. It is the old-style blue lens that old 3D systems used many years ago. It is NOT the cyan lens that modern anaglyphic 3D systems use today!!!
Why is this important? Answer: Modern anaglyphic 3D systems that use a red filter, switched away from blue and changed to cyan for the second filter many years ago. Cyan is equal parts green and blue---so it has a greenish blue appearance and most cyan lenses in 3D glasses are not as dark as the older blue lenses. The reason the switch was made from blue to cyan is because of the way color is divided between the two filtered lenses. One way to measure color is with the HSB model (hue, saturation and brightness). Hue is the chroma value and it is measured on a circle from zero to 360 degrees. Red is at the top at zero degrees and cyan is at the bottom at 180 degrees. Because red and cyan are at exact opposites on the color circle, they evenly divide all visible color between them, making cyan a better choice to separate the two frames of a 3D image when red is used for the first filter. The color blue has a hue of 240 degrees and does not evenly divide the visible color spectrum with red.
What happens when you view a modern red+cyan anaglyphic 3D movie while wearing red+blue glasses? Answer: Because the blue lens cannot filter green as it should, the cyan frame of the 3D image is not properly filtered and green light is allowed to pass to the wrong eye. The audience sees an offset green image that confuses the picture and degrades the picture quality.
I've written to the seller HXYTECH and will update this review if they correct the problem. In the meantime, stay away from these glasses if you need red+cyan because you won't get it here.
Note: Many folks who enjoy 3D movies are using a Windows PC and CyberLink's PowerDVD software to do it. PowerDVD can combine the two frames of a modern 3D movie on a 3D blu-ray disc into a single anaglyphic 3D frame. This enables you to watch 3D movies on any 2D HDTV or even a 4K UHD TV or monitor. But the only kind of anaglyphic 3D frame that PowerDVD can create is a red+cyan one. It does not offer any other color options. You must have red+cyan glasses for the 3D effect to be seen correctly. Red+blue glasses will create an offset green image that will ruin the picture as described above.