what is color phase exactly? at DVinfo.net

Cal Bickford · March 17th, 2007, 07:56 PM

hi guys, wondering if someone could tell me exactly what the color phase setting does. I can't seem to find much info on it....

Steve Leverich · March 17th, 2007, 09:39 PM

I don't have an A1 (yet, but soon) but everywhere else in the video world you can call it "tint" - try adjusting the "tint" control on your television to see what it does - then aim your cam at someone's face (with good light) and see if adjusting the phase control does the same thing... Steve

Have you checked page 65-67 of your manual?

Cal Bickford · March 18th, 2007, 04:49 PM

yeah, the manual doesn't give much information at all about the cph setting. But it being a "tint" function makes sense.

John Miller · March 18th, 2007, 05:59 PM

Phase is the strictly correct term for what is often termed "tint" or "hue" on consumer equipment.

It is really on of significance for NTSC video. It refers to a phase difference added to a colour reference signal used to decode the colour information. (PAL video removes the need for a colour reference signal using a technique that inverts the phase every video line - hence the term "Phase Alternating Line").

See http://en.wikipedia.org/wiki/NTSC#Color_encoding for description of how the colour information is encoded for NTSC.

Bill Ravens · March 18th, 2007, 07:09 PM

if you can envision the colors on a rainbow, the analogy is to a wheel of color, where primary and complimentary colors are juxtaposed on a continuous circle or wheel. Thus any primary color, when combined with its opposite on the wheel, yields a neutral gray, luminance with no chroma. Now, if you can wrap that around your brain, think if phase difference as a rotation of the wheel. So that a phase difference of 180 degrees is the complimentary color, a phase difference of 360 degrees returns to the original color, and so on.

Cal Bickford · March 18th, 2007, 10:43 PM

wow! thanks john, thanks bill! Thats exactly what I was looking for, i can't imagine a more straightforward response explaining color phase technically and conceptually. These boards a great! A big thanks to everyone who answer all my silly questions!

Greg Boston · March 18th, 2007, 10:50 PM

This is what the vectorscope is for. It displays color phase information to you as well as saturation. As was stated, a given color in the NTSC system has a phase relationship to the reference signal (chroma burst). The AMPLITUDE of the chroma burst signal determines color saturation. So, when you look at the vectorscope, the display will show a given color as a position on the circle and the saturation will determine how far away from center the display is.

-gb-

March 17th, 2007, 07:56 PM	#1
Cal Bickford Regular Crew Join Date: Jan 2007 Location: Austin, TX Posts: 157	what is color phase exactly? hi guys, wondering if someone could tell me exactly what the color phase setting does. I can't seem to find much info on it....

March 17th, 2007, 09:39 PM	#2
Steve Leverich Regular Crew Join Date: Sep 2006 Location: Albany Oregon Posts: 173	I don't have an A1 (yet, but soon) but everywhere else in the video world you can call it "tint" - try adjusting the "tint" control on your television to see what it does - then aim your cam at someone's face (with good light) and see if adjusting the phase control does the same thing... Steve Have you checked page 65-67 of your manual?

March 18th, 2007, 04:49 PM	#3
Cal Bickford Regular Crew Join Date: Jan 2007 Location: Austin, TX Posts: 157	yeah, the manual doesn't give much information at all about the cph setting. But it being a "tint" function makes sense.

March 18th, 2007, 05:59 PM	#4
John Miller Major Player Join Date: Oct 2005 Location: Hillsborough, NC, USA Posts: 968	Phase is the strictly correct term for what is often termed "tint" or "hue" on consumer equipment. It is really on of significance for NTSC video. It refers to a phase difference added to a colour reference signal used to decode the colour information. (PAL video removes the need for a colour reference signal using a technique that inverts the phase every video line - hence the term "Phase Alternating Line"). See http://en.wikipedia.org/wiki/NTSC#Color_encoding for description of how the colour information is encoded for NTSC.

March 18th, 2007, 07:09 PM	#5
Bill Ravens Join Date: Nov 2001 Location: santa fe, nm Posts: 3,264 Images: 10	if you can envision the colors on a rainbow, the analogy is to a wheel of color, where primary and complimentary colors are juxtaposed on a continuous circle or wheel. Thus any primary color, when combined with its opposite on the wheel, yields a neutral gray, luminance with no chroma. Now, if you can wrap that around your brain, think if phase difference as a rotation of the wheel. So that a phase difference of 180 degrees is the complimentary color, a phase difference of 360 degrees returns to the original color, and so on.

March 18th, 2007, 10:43 PM	#6
Cal Bickford Regular Crew Join Date: Jan 2007 Location: Austin, TX Posts: 157	wow! thanks john, thanks bill! Thats exactly what I was looking for, i can't imagine a more straightforward response explaining color phase technically and conceptually. These boards a great! A big thanks to everyone who answer all my silly questions!

March 18th, 2007, 10:50 PM	#7
Greg Boston Wrangler Join Date: Oct 2003 Location: DFW area, TX Posts: 6,117 Images: 1	This is what the vectorscope is for. It displays color phase information to you as well as saturation. As was stated, a given color in the NTSC system has a phase relationship to the reference signal (chroma burst). The AMPLITUDE of the chroma burst signal determines color saturation. So, when you look at the vectorscope, the display will show a given color as a position on the circle and the saturation will determine how far away from center the display is. -gb-