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## #1 2005-09-14 03:16:53

hdesai
Member
Registered: 2005-09-10
Posts: 2

### Couldnt Be Difficult

i am a free-lance computer programmer. as i cannot afford it i cannot engage services of another professional for this problem. i have tried it in excel, but manually found acceptable answers, i would be grateful if someone could help me.

i have a ratio of 3:2.25:1.6, when i feed that into the system the returns that are "acceptable" are 225:277:359, or infact also 225:276:359. now this is for a color lab where the RGBs and YMCs are required to be in some proportions!!!

i need to find out the calulating formula to arrive at the results. e.g. from trial and error i have found the above answer, also another example is 3.5:2.2:1.6 returns 226:319:348.

what is this relationship called. Definitely there are some relations between the ratios, WHAT IS IT????!!!!!!!

tks a ton
hdesai

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## #2 2005-09-14 03:18:25

hdesai
Member
Registered: 2005-09-10
Posts: 2

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## #3 2005-09-14 05:06:01

ryos
Member
Registered: 2005-08-04
Posts: 394

### Re: Couldnt Be Difficult

Someone correct me if I'm wrong:

A number can be constrained to proportion by multiplying by that proportion.

For example, if I have a ratio of 4:3, if I choose 640 as my first number, I multiply it by 3/4: 640 (3/4) = 480. If you want to go from 480 to 640, do the inverse: 480 (4/3) = 640.

Now let's extend it to a ratio with 3 terms: 4:3:2. We know that 640:480, so the third term is found by multiplying by 2/3: 480 (2/3) = 320.

You can find any term in the ratio based off any single term by multiplying by the correct ratio. So, to find the first term from the third, we multiply by 4/2 = 2: 320 (2) = 640.

Good luck.

El que pega primero pega dos veces.

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## #4 2005-09-14 05:46:53

kylekatarn
Member
Registered: 2005-07-24
Posts: 445

### Re: Couldnt Be Difficult

hdesai wrote:

WHAT IS IT????!!!!!!!

Information Technology

Last edited by kylekatarn (2005-09-14 05:47:13)

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## #5 2005-09-14 09:40:52

MathsIsFun
Registered: 2005-01-21
Posts: 7,660

### Re: Couldnt Be Difficult

(IT = Information Technology ... LOL)

It is a bit strange.

You say  3:2.25:1.6  in another system is  225:277:359

But this is obviously not a direct ratio, for example 3 is nearly double 1.6, but there is no doubling between 225 and 359 (even though they are in opposite locations)

Also 3.5:2.2:1.6  in another system is  226:319:348

And we know it is something to do with color, which is often represented as a three-dimensional space

So, you could be dealing with different ways to locate a point in 3D space.

Could you give us some more info behind each system?  (RGB, Hue/Saturation/Brightness, Luminance/a/b are some I have heard of)

"The physicists defer only to mathematicians, and the mathematicians defer only to God ..."  - Leon M. Lederman

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## #6 2005-09-14 10:11:07

John E. Franklin
Member
Registered: 2005-08-29
Posts: 3,588

### Re: Couldnt Be Difficult

Also CYMK is Cyan, Yellow, Magenta, and Black.  This is used when mixing pigments.
RGB is used to mix light, as in a computer screen, a TV I think.
But what is interesting is when you mix all the pigments together you get a dark color like brown or black.
But when you mix light together, the colors get brighter, and head toward white.

igloo myrtilles fourmis

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