General Question

girlofscience's avatar

What is are the numbers for these color combinations?

Asked by girlofscience (7537points) March 13th, 2009

Using the RBG color model, what combinations of red, green, and blue should be used to achieve these colors in between red and blue?

Red is (255, 0, 0)
Blue is (0, 0, 255)

I also need to create:

- 50% red, 50% blue
– 75% red, 25% blue
– 25% red, 75% blue

For 50% red, 50% blue, do I make it (255, 0, 255) or, like, half of each, as in (128, 0, 128)?

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18 Answers

cwilbur's avatar

The RGB model shows the intensity of that component of the color. As long as the numbers are equal, you get 50% red, 50% blue, but the intensity will vary.

Basically, the idea of “50% red, 50% blue” doesn’t map well to the RGB color model. You might be better off working out what the numbers are in HSV (where that concept does make sense) and converting.

dynamicduo's avatar

I was playing around in Photoshop with the RGB values to prove my theory, and I noticed that when you change the RGB values from 255/0/0 to 128/0/128, the HSV values also change to compensate, and changing those back to their other values causes the color to change. Thus I support @cwilbur‘s conclusion, and have to say to you that I don’t know if you can do this solely within the RGB landscape.

AlfredaPrufrock's avatar

Would a Pantone to RGB conversion chart help? I found this chart. You find your PMS number, and it has the RGB proportions to match that color.

SeventhSense's avatar

@AlfredaPufrock
Wish I had access to her PMS number…it would have made life simpler..

Sakata's avatar

are the numbers for these color combinations” is a question, a fragmented sentence, bad grammar, and a post containing a misspelled word.

Did that answer the question?

AlfredaPrufrock's avatar

It might be helpful to know what the purpose is of the color conversion exercise? Are you morphing from 255 R to 255 B across a spectrum?

girlofscience's avatar

@Sakata: :( I am really, really sorry for my typo(s). This was one of the lowest-quality questions I have ever asked on Fluther, but I was pretty frustrated earlier today when I was trying to figure this out. So I went on Fluther and typed it out quickly without reviewing and rethinking. Other than this, I have never been so careless with my posting, so it was kind of mean for you to say what you did. I’m not a repeat offender when it comes to “bad grammar,” so couldn’t you have cut me some slack? And clearly, no, that did not answer my question.

girlofscience's avatar

As for the other people, thank you for the advice and possibilities.

@AlfredaPrufrock: The purpose of this color conversion exercise:

I do research in visual perception and was programming an experiment that involves a discrimination exercise that can be easier or harder, based on how different the colors are. Surprisingly, this is the first experiment I’ve done that seriously involves the concept of color, which explains my confusion when trying to mix these colors.

AlfredaPrufrock's avatar

I think the RGB factor is what makes it hard. I seem to recall something about this back in the dark days when I took a color seminar at RIT on buying printing. When you think color, you think reflective, CMYK on a solid sheet of paper, white reflecting the light. With RGB, the light comes from the back, and there is no reflection. So what does that do the math on this question? 255 is full saturation Red, and you want to morph it to 255 full saturation Blue, incrementally, but not in a light spectrum ROYGBIV because you’re not factoring G. It’s been a long time since I’ve thought about this…

I think you need to know how “brightness” and “lightness” will affect the color. Try this site and see if it helps. It has the math around RGB proportionality and “lightness” and “brightness”.

this question is going to haunt me until I understand it!

Where’s Jayne?

girlofscience's avatar

@Sakata: What’s so funny!?

Sakata's avatar

@girlofscience You’re a teepee. You’re a wigwam.

girlofscience's avatar

@AlfredaPrufrock: Yes, indeed! I do need to eliminate brightness and lightness as confounds. I spent the rest of today finishing up coding the experiment with pretend values (I just did like, 64, 0, 191), so at least the rest of it works, but I’m going to start running it next week, so I need this stuff to be accurate before I start to run subjects. I will check out the site you recommended, but right now, I am on my home computer and not in front of my programming software and also had several margaritas at dinner.

girlofscience's avatar

@Sakata: :( :( :( :( :( WHY?????????????????

Sakata's avatar

Patient: Doc, I keep having these dreams. First I’m a teepee; then I’m a wigwam; then I’m a teepee; then I’m a wigwam. It’s driving me crazy. What’s wrong with me?

Doctor: You need to relax. You’re two tents.

girlofscience's avatar

@Sakata: Not funny enough. + that’s just how I always am, and I love it! = productivity.

Sakata's avatar

@girlofscience Well, for me, waking up and taking a piss = productivity so it’s not that grand of a scale from which to measure.

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