someone asked about explaining color gamut in laymans terms. Very hard to do for the average person. Even experts don't understand it all.
Id suggest visiting wikipedia for a description. They also have some good pictures that makes it easier to visualize.http://en.wikipedia.org/wiki/Gamut
Very basic explanation (i'll try)-Sunlight
- biggest gamut ever. Color spectrum has around 9 colors(red, orange, yellow, yellow-green, green, blu-green, blue, violet, purple, i may have missed or added one)) it can use to make additional colors. No technology can recreate it with todays technology. Displays the most colors and which is what we are used to as we see this every day in real life. This is why TV's/monitors/prints never look like certain colors are rightIndoor lighting
- smaller gamut - this is why colors outdoors look different indoors. The light source from indoor lighting has a smaller gamut so it produces a smaller range of colorsTV/monitor
- even smaller gamut using RGB (red,green,blue) Also with colors wheels the wheels are supposed to separate white light from a lamp. The blue filter in the wheel should absorb all the light except for the blue. In reality depending on the quality of the wheel and the impurities the blue filter may only let 95% of the blue light through and in addition may let 5% of red, green...etc escape which mixes with the blue. DLP sets that use wheels with 5 or 6 colors in them can produce a larger gamut as now you use 5 or 6 colors to produce other colors. The more colors you can use to make colors the bigger your gamutLED DLP
- Red,Green,Blue LED. Gamut is supposed to be 140% of traditional lamp based DLP. Also seems to be brighter In LED DLP tv. In general LEDs are dimmer than traditional lighting. Since they don't burn as bright as lamps might be why they have a longer half life and lifespan of 20000 hours compared to lamps that are 3000-5000. Since they are dimmer than lamps then why do we get a wider gamut and brighter image? I believe this is because of the color wheel in lamp based DLP. A color wheel is a filter. Due to the quality of the filter and how pure the filter is some of the light is absorbed which shouldn't be and some colors that should be asorbed leak out. Because of this the final result isn't as bright and the color gamut is smaller for lamps based dlp with color wheels.
Compare this to putting sunglasses on. Your basically putting a black/gray filter over your eyes. In doing so colors are muted and brightness is cut down. You can also compare this to a printer. Print something on white paper and the colors look vibrant and robust. The white paper is the lamp and the toner/ink are your filters. Take the same printer and print the job on black paper. You see very little color because the lamp is black. This would be an extreme case of impurities. The black paper is so impure that it diminishes the brightness and color gamut. To a less extreme print the job on blue paper. Now you will see colors. The blue in the paper though is the impurity so it absorbs all colors in the gamut except blue. You will notice the print doesn't look as good as what was done on white.
This is also why you can buy regular white paper or premium bright white papers. The brighter the white paper the better the image quality and color gamut. Also note that premium paper costs more as they have to use the best ingredients and manufacturing techniques to produce the paper with less impurities.
IF manufactures made TV's that were 100% pure white light (can't be done yet) and 100% impurity free color wheels then the TV could produce identical colors to what we see in real life. Also would cost an arm and leg to do and wouldn't be cost effective.
Now picture 3 triangles. Each corner of the triangle represents Red, Blue, or Green. Sunlight is the largest gamut and triangle. Take two of the triangles of smaller size and gamut and center them in the sunlight triangle. You will see these cannot produce colors outside their own triangle. If a color falls outside the triangle then it somehow gets mapped into the triangle for that displays color gamut. To even further complicate this shift one of the smaller triangles in one directions. Now what you will see is this gamut may be able to pick a wider range of colors in 1 corner of the triangle while the other 2 corners move inside the gamut of the other device so now those colors are limited.
Say you have a color called RED 100 that you see in real life outside. If you put this info into your TV and it is within the gamut (triangle) of your TV's display then its perfect. You will think it looks normal on screen. So the bigger the gamut your TV has the better chance the color will be what you are used to seeing. Now if this RED 100 isn't in the gamut for your TV then your TV cannot display this color. So what it does is it has to pick the closest color. Some Color mapping tables will just map this red 100 to the closest red color in the triangle. So now your REd100 may be picked as Red75. Now you look at in on TV and you say whats wrong with the color. Some technology will just map all colors outside the gamut to the closest value and all colors in the gamut stay put. Problem with this is if you already have colors in your scene that use RED75 then now your RED100 is now also RED75. If these colors were next to each other in the scene now you have issues with banding and transition from color to color. Other technologies will take the RED100 and map it to RED75. One formula will look at this and say minus 25. So now all colors that are in the gamut already have 25 subtracted from them. This way we don't get overlap. The REd100 mapped to REd 75. The Red 75 that was in gamut now becomes red 50 (75 minus 25). But this can apply to all color in the gamut so now all your colors look wrong. Another one will use the percentage and not the full value (25). Since colors have to shift and such the best image usually is a screen that has the biggest gamut so no colors have to be shifted.
Anoter method is a look up table where a color scientist looks at the colors that fall outside the color gamut and then make a table that will pick the best match within the gamut. This match may be very close where the average user can't tell it was mapped. Other colors just can't be represented right so they pick the best color which still isn't right. Example would be metallic silver. How often does silver just look gray on monitors/photos/prints.
In addition everything is relative. Everyone eyes perceive color differently. A good red to me may look bad to someone else. If you look at green here in the US it tends to be a darker, fuller vibrant green color. You take that to europe and they go yuk that isn't green. If you take their idea of green and bring it here, it looks lighter and more washed out and we say whats wrong with that?
sRGB is a color gamut that is pretty standard on Monitors/TV. Since the LED DLP can now do a wide gamut (140% more) people may look at wide and be like whats wrong with this. Even though the colors are now more accurate as this wide should better simulate real life we may be so use to seeing sRGB monitors and TV where now we go Whats wrong with this. So this is why they give you the option between selecting what you want and not just letting it do the full tv gamut of Wide.
Again look at the more technical description in Wikipedia and see if it makes more sense.