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Blue-only color bars?
Is there an NTSC blue-only tiff file or something that could help calibrate monitors and TVs that don’t have a blue-only switch?
Just a wild-ass idea I had this morning, I’m using a Sony multi-format TV for HD for clients, and I have it pretty well dialed in, just would like blue-only to get it closer. Any idea how to make one in Photoshop? Or, would it work?
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17 Replies
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Seems to me that you could create this in FCP. Just add a RGB balance filter to a clip of color bars, then kill r and g…? The bars would come out with the blue only output that way… dunno if you could actually setup a monitor with this output, but I’m not sure why not either… interesting idea! give it a try and report back!
Jerry
Apple Certified Trainer
Author: “Jerry Hofmann on Final Cut Pro 4” Click here
Dual 2 gig G5, AJA Kona SD, AJA Kona 2, Huge Systems Array UL3D
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That wouldn’t work because you need to have all the colors coming to the monitor. You could easily get a blue filter. The article below says a Wratten 47B is the one you want.
https://www.synthetic-ap.com/tips/calibrate.pdf -
Tom,
That does not make sense to me. Of course all the colors would still be there, how would you get a TV to not do that? The blue filter idea is something I’ve always done, but I think it’s a crappy alternative to a blue only switch.
I’m gonna try Jerry’s suggeation and see what happens.
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As long as we are using that “just blue” bars to calibrate only the Chroma, I think the way that Jerry points works. is the same that you get rid of the G an R in your computer or in the monitor. We can not usethat bars to calibrate the bright or the contrast, but the chroma, I tink, yes.
Cheers,
rafael -
Chroma gain, maybe. Phase, not a chance.
George
Light Images -
Hey George,
Yeah, chroma yes, but you are right. Back to the ole’ blue gel I guess, but then, phase isn’t much of an option there either, depending on the controls in the monitor, no?
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Adjusting hue is a process of comparing the various colors to each other so that they are in the correct balance, right? So, if your source image only has one color, how can you compare anything?
When you use the blue-only switch you are seeing all the colors of the source through only the blue gun. You are seeing yellow, cyan, green, magenta, red, and blue through the blue gun only. When you adjust the hue and chroma controls, you change the balance of those colors and you’ll see the intensity of the individual areas change with respect to each other–again, all through the blue gun only.
With a blue-only source, you’ll get no comparison and thus no change in intesity between, say, the yellow and cyan bars. They’ll all change in usison and thus defeat the comparison you’re trying to make.
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Chroma won’t work with this method either. You’ve subtracted the other colors out of the white, so you get no comparison of blue and white bars.
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It’s probably better to buy a monitor with the ol’ blue only button on it…
Jerry
Apple Certified Trainer
Author: “Jerry Hofmann on Final Cut Pro 4” Click here
Dual 2 gig G5, AJA Kona SD, AJA Kona 2, Huge Systems Array UL3D
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Posts like this one make me glad I am in PAL land.
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