# Color Matching Using RGB Values



## rhyman (Apr 19, 2009)

Nothing is more frustrating than trying to make sense of the names that paint manufacturers give to their various colors. Why is one manufacturer’s “Light Cinnamon” color actually darker than another’s “Cinnamon” color? Ever try finding a spray paint that matches the color that you use for brush painting? Good luck!

I have found that the only way to get close when trying to match colors is to forget about whatever name that is on the container and to only go by the RGB value. RGB stand for RED – GREEN – BLUE. Each of these three values can vary from 0 to 255. Every color can be represented by a numerical representation of the red, green and blue content. 0, 0, 0 would be pure black and 255, 255, 255 would be pure white. This allows over sixteen million different colors.

Here are some examples of a few browns, with the theoretical pure black and pure white at the top and bottom:










The only problem is that the manufacturers usually don’t provide the RGB value for their colors. Fortunately, there is somewhere you can go to find out. There is a free web site that gives the RGB value for just about any paint in the world. It is 
http://www.art-paints.com/Paints/Art-Paints.html

I use this site whenever I need to match a particular color, or when I want to do a “side-by-side” comparison of two different shades of the same color. The web site is really designed for artists, but – after all – aren’t we all just artists that paint on a different canvas?


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## Garratt (Sep 15, 2012)

You need to understand the difference between additive color and subtractive color mixing. 


When dealing with light such as on a computer screen you are using additive color masde up of the 3 primary colors: Red, Green and Blue of which when all blended equally in full intensity you end up with white. 

Artists have a hard time painting skies in a sunset because blue will blend into pink in light with the intermediate additive colors but to blend that with pigments you end up with a murky grey. It has baffled them for centuries.

When dealing with pigments you are using subtractive color made up of the 3 primary colors: Magenta, Cyan and Yellow of which when blended equally you end up with black (If the pigments were perfect primaries which none are, so you end up with that grungy off black instead. That is why the printing industry uses a four color system with black printed separately.)

Interestingly enough, the 3 secondary colors of light are the 3 primary colors of pigment and the 3 secondary colors of pigment are the 3 primary colors of light. 

Finished paint colors are not derived from pure primary colors though. they are a blend of base colors and pigments which have a formula. 
An RGB value for color mixing of paint is useless because the theoretical primary colors are totally different and you don't blend primary colors anyway unless using 3 or 4 color systems as in the printing industry.

Andrew


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## rhyman (Apr 19, 2009)

Andrew,
Did you bother to read my post before you decided to criticize it and show everyone how smart you are?

The post was not about mixing paint ... it was about an easy way to examine different commercially available paints and determine how close they are in color.

I fully understand the difference between additive and subtractive. In fact I have published articles on color theory and even given model railroading clinics on the subject.

The average modeler doesn't really care about RGB or CYMK or even theories of any type in general. What they usually want is a tip on how to do something that is quick, easy, and cheap. That's all the post was meant to convey. It is folks like you who really deter others from trying to share information with our fellow modellers.


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## bnsfconductor (Jan 3, 2008)

Interesting list, but I didn't see Polly Scale listed any where. Since PS is going bye bye this information would be useful to match the PS colors with something equivalent. 

Craig


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## Dwight Ennis (Jan 2, 2008)

Looks like the CYMK values are also given. Thanks Bob. This should prove useful.


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## Naptowneng (Jun 14, 2010)

Very Cool! I looked up the various "similiar" oxide primers I use, and now finally have a baseline value for their colors so I can compare them and decide which ones I like for which cars. 

Thanks 

Jerry


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## Greg Elmassian (Jan 3, 2008)

Yep, I was questioning why listing RGB when most people would be using CMYK... (The only thing using RGB is something EMITTING light) but I went to the link and the CMYK was shown as Dwight mentioned. 

Always good to read a post thoroughly and read the link provided first.









I have the same problem, a number of recent threads had the basic statement and links supporting it, but most of the people arguing did not read any of the links. 

Nice resource for all of us Bob, and thank you.









Greg


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## Scottychaos (Jan 2, 2008)

Well, its a start..
but then you have another major problem.. the problem of paint manufacturers themselves not even being remotely accurate! 
LV Cornell Red is a great example..
Here is the Testors Cornell Red, from that site:

Testors LV Cornell Red, from art-paints dot com

That is so "not even close" its not even funny..
when I plug their RGB values into photoshop:
RGB # 102, 57, 60
I do get the hideously awful color they indicated:










Which, as I said, isnt even close to reality..
it should look more like this:










How could they be that far off??
are they just guessing? 

Scot


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## Greg Elmassian (Jan 3, 2008)

Well, to start are you using a calibrated monitor? 

Greg


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## Garratt (Sep 15, 2012)

Bob, I just stated the facts.
I can see your point of comparison but when we have this information of how close a color is then what do we do with it?
Perhaps just add a dash of 'more right' additive? Ha ha. You may as well just use arbitrary words like close closer and closest.
There is even more I could go on about but what is the point if it becomes complicated. You can believe what you want but I know better and have a sharp matching professional eye that needs no numbers or numerical delusions. How this data is measured can become questionable in itself compared to the real world situation. 

You share, I share. I deter nothing by conveying correct information. Your ego is just hurt so don't give me that rubbish. 
Thanks for the link though Bob, it is of some use until reality is discovered. No conversing though people. Bob said something, he has the 'smart hat' on today. Ha!










Andrew


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## Garratt (Sep 15, 2012)

Scot, You demonstrate my point exactly. Calibrated monitor would help but the same problem would still exist. 

Testors B&O Royal Blue 

Testors B&O Royal Blue from the above mentioned site and my color corrected image bottom.
I believe Aristo-Craft got it fairly close to prototype color. 
I may not be perfect but better than some delusional process. 

Andrew


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## Greg Elmassian (Jan 3, 2008)

Yes, the last time I posted, Scot's pictures did not show, although I took him at his word that the colors were way off. 

Oh well, if these are RGB /CMYK values from the manufacturer, then it appears that not all are really accurate. 

I prefer panatone colors, because you can purchase a panatone set, and you can accurately calibrate a monitor and or a printer to that set. 

Greg


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## Scottychaos (Jan 2, 2008)

More fun with color! 











The webpage that goes with that photo:
Bath and Hammondsport Railroad Color 

Scot


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## Gary Woolard (Jan 2, 2008)

Once again I am simply confused! I used the link to the art-paints site, and found all sorts of categories of paint types. Then brands. But I couldn't find that comparison table, OR one for CMYK values, anywhere. Did a search which just sent me to different brands.

What am I missing here?

-Color Me Confused--


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## Greg Elmassian (Jan 3, 2008)

Drill down deeper, to the final color... 

Greg


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## Garratt (Sep 15, 2012)

Another aspect I found with the RGB values on the art-paints.com website is their RGB values are one based rather than zero based as used in an 8 bit computer number so the values for their own color samples are all out by one. How they derived the values is anyone's guess but the colors are nothing like the actual color, not even remotely close. 
It is beyond monitor color calibration, additive/subtractive color, color shifts etc. The concept of the website is possible and could be close to accurate, it just has to be done by those that are not incompetent.

Andrew


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## Garratt (Sep 15, 2012)

Posted By rhyman on 05 Jul 2013 10:43 AM 
Andrew,
Did you bother to read my post before you decided to criticize it and show everyone how smart you are?


Bob. It is not a matter of how 'smart' I am, more of a case of how 'dumb' some are. I was assuming I was responding to a novice but apparently not, just plain old cognitive dissonance it seems. Did you test any? 
I am aware of the consistency in the erroneous color data which would make it easy to fix but life has taught me to not cast pearls before swine. I will let the so called 'experts' fix it. Ha! I'll leave my hat on. I wouldn't be a bit surprised if these colors are never corrected on the website even after they have been notified. It is all too common these days for some to believe whatever suits them and convey nothing but deluded nonsense. 


Santa Fe Blue?









Santa Fe Red?










PRR Maroon?









CSX Blue?


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## armorsmith (Jun 1, 2008)

Gentlemen, 

From lifes experience with paints, there are so many variables I can't list them all. However I can tell you that ALL paints start out with a white base that is manufactured using titanium. Direct from a paint manufacturer I was told that final colors can vary, with all other factors being equal, by the quality of the titanium in the base white. I have personally ordered the same formulation (manufacturer's coding) and received two colors that were considerably different. Manufacturer's fight this color match issue today, especially when the color is trademanked. Even with today's technology color variation exists and can be a thorn in one's side. 

Now lets look at some of the other variables. The first one I want to explore is, 'Does anyone have the original formulations for the paint colors we are trying to replicate?'. Probably not. Now lets factor in that most of these colors are trying to be replicated from photographs (some even black and white). Now add in the quality of the emulsions of the photograph paper, the care and condition of the photograph at the time the evaluation was made, the lighting when the photo was taken, and the list goes on. 

Scott above is holding color chips against a prototype. I think that is a great method to match THAT locomotive at THAT specific lighting condition at THAT specific point in the degradation of the paint itself, and I could go on here as well. Scott's method is probably as accurate as we can get without the original formulation or a "new condition" paint chip to match. Considering ALL paints fade over time, does a little difference in shade make that much difference? IMHO no it does not. 

Again, what you see on the screen may or may not be exactly what you are going to get 'in the can'. Many of the same manufacturing variables exist in the manufacture of the screen you are viewing on that are in the manufacture of the paint itself. Most of the older CRTs had adjustments for color and hue. Where is the perfect setting? The NetBook I am working on does not have these settings, I am relegated to the screen manufacturer's idea of 'perfect settings'. 

My intent was not to lite any fires, but to bring out that there are way too many variable that affect what we 'see' to get too wrapped up in minor shade differences in paint color. Find a color that matches what you believe the color should be and go with it. In most cases I don't believe that anyone has the 'real' color anyway. And should someone make a liar of me, please post the specifications for the specific color so we all can 'get it right'. 

FWIW, 

Bob C.


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## Scottychaos (Jan 2, 2008)

Posted By armorsmith on 08 Jul 2013 12:24 PM 


Scott above is holding color chips against a prototype. I think that is a great method to match THAT locomotive at THAT specific lighting condition at THAT specific point in the degradation of the paint itself, and I could go on here as well. Scott's method is probably as accurate as we can get without the original formulation or a "new condition" paint chip to match. Considering ALL paints fade over time, does a little difference in shade make that much difference? IMHO no it does not. 



Bob C. 



Lighting condition shouldn't be a factor..because the locomotive and the color chip are being lighted equally..

could be cloudy, sunny, raining, snowing, dawn, dusk..makes no difference..your "best chip match" will still match the color of the locomotive, lighting simply isn't a factor.

but otherwise, I agree with everything else..

Scot


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## Semper Vaporo (Jan 2, 2008)

Posted By Scottychaos on 08 Jul 2013 05:04 PM 
Posted By armorsmith on 08 Jul 2013 12:24 PM 


Scott above is holding color chips against a prototype. I think that is a great method to match THAT locomotive at THAT specific lighting condition at THAT specific point in the degradation of the paint itself, and I could go on here as well. Scott's method is probably as accurate as we can get without the original formulation or a "new condition" paint chip to match. Considering ALL paints fade over time, does a little difference in shade make that much difference? IMHO no it does not. 



Bob C. 



Lighting condition shouldn't be a factor..because the locomotive and the color chip are being lighted equally..

could be cloudy, sunny, raining, snowing, dawn, dusk..makes no difference..your "best chip match" will still match the color of the locomotive, lighting simply isn't a factor.

but otherwise, I agree with everything else..

Scot

If the color chip and the locomotive were truly the same color then you would not be able to see the color chip if it was held against the side of the locomotive!

But...

The material the paint is on will make a difference even if the paint is from the same bucket using the same brush, painted within seconds of each other. 

The surface texture of the material will also affect the apparent color/hue.

The physical shape of the material will also make a difference... Curved vs flat.

Of the color "chips" shown in the postings here, they vary in color based on how my laptop screen is tilted and whether I am sitting up straight or slouched ,or leaning left or right.

NBC (the TV network) used to have a women in their employ who had what was considered "perfect skin-tone". She was PAID to travel to all the various NBC stations/affiliates so the technicians could adjust their cameras to provide the same color output to get the various television programs to look uniform. But if you go to a store that sells TVs and look at the wall of sets on display, all showing the same video/show, you will see large differences is brightness, hue, and contrast (and even in the shape of objects) based on how the set was configured at the factory (or adjusted by the in-store personnel).

I took the SAME paint chip off my house to the paint store on 3 separate days and gotten 3 different "formulations" for what color it was... all were similar but were not the same numbers for how much of each pigment to add to the can of paint.

Professional painters will open all the buckets of paint in a purchase for one project to combine them because the color will vary from one bucket to the next and it can be distracting to see where the wall of a house changes color slightly where they opened the next bucket of paint if they don't mix the buckets.


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## Ironton (Jan 2, 2008)

Scot, 

The lighting conditions do matter. Consider the following. 

Hold a piece of colored plastic or some other material in front of your eyes. Now do the color matching. This is most notable if the plastic was colored one of the primary colors. No remove the plastic and look at your color match. Is it the same? Probably noticeable not the same. 

This is the reason that if you work under shop lights a painted model will look different outside than when you "matched" it to a picture in your shop. Whether they are fluorescent or tungsten (old style bulbs that are being "phased out") the light does not have the same mixture as natural sunlight. So some of the bands do not show. 

As far as additive/subtractive goes, if you are mixing the color it matters. If all you are doing is looking at the result it does not matter. What the eye sees is the same result.


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