Preserved Topic: Any relationship bet. Hue/Sat. & RGB colors? (Page 1 of 1)

Hello I kind of do not understand the Image/Adjust/Hue-Saturation command.

Is there any relationship between the cmd. above and the available foreground/background color, and RGB color values? Thx in adv!

tfm. r it. =)

it lives

pshopuser: those are all completely different things. Read the manual is very good advice there, color's a way big deal you know, prolly too deep to do justice to right here.

Jason

play with the sliders, clicking the 'colorize' box, and you'll see what it does...


"...when I'm high like heaven, when I'm strong like music, 'cause I'm slow like honey and heavy with mood..."
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"is there any relationship ...."

Yes, but it's not real obvious. There are a number of triad color spaces: LAB, HSB, HSV, RGB to name a few.

RGB establishes direct values; a CRT screen fires its guns in relationship to that. It's sort of a "volume control" for each color. The other triad systems are a little more obscure. LAB for instance: "L" represents lightness; "A" and "B" are color opposite channels: blue/yellow, red/green. It's not too obvious. HSV - one channel is hue (what color), one is saturation (how pure is that color - how close to or far from gray) one is value - where does it fall between black/white.

All the triad systems can pretty much describe exactly the same "color"; all of them have a relationship to each other, and roughly the same gamut. It's just a matter of how you choose to describe a given color. Change the "L" in LAB and you will also see the RGB values change in the color picker. Change the "S" in HSV, and you will see the numbers change. I think RGB is easier to understand, but there is a reason for the existance of the others too. For instance, if the color of an image is right on, but it's too dark, adjusting the "L" channel in LAB might be a good strategy.

[This message has been edited by Steve (edited 01-02-2002).]

HSV vs. HSB -- been meaning to ask -- is there a real difference? Rather, what is the difference?

Is Value measured 0.0 - 1.0 and Brightness is measured is measured 0 - 255 or something?

Personally, I use them interchangably, but it would be nice to get the context right if there is a difference.

There must be some difference to a software engineer / color scientist, but for everyday purposes I too think of them as interchangable.

I made this http://www.gurusnetwork.com/tutorials/misc/colorchooser.html a while ago, it uses the relationship between RGB and HSV to keep the two sets of values consistent when you change one or the other. First, read the explanation of it at the bottom of the page, I think I explained the relationship a bit there. Then, look in the source code and at http://www.gurusnetwork.com/scripts/color_chooser.js . The functions ResetRGB() and ResetHSV() figure out the HSV or RGB values to correspond with the RGB or HSV values specified, respectively. It's not exactly simple, though. Good luck.