Is there a good way to identify the color values of a particular shade?

[Orrex]

Looking for a way to determine either the RGB* values or hex code for a given color, for purposes of a very informal CAD project. I have several physical object whose colors I need to represent, and aside from eye-balling them next to an online color chart, I can't think of how best to do it.

* RGB refers here to red/green/blue and not the sadly departed Ruth Bader Ginsberg, alas.

[ZZenith]

1. Can you get hold of a Pantone spec book?

[Orrex]

4. Possibly. That might be a good way to go.

[ZZenith]

7. Put the object and the specifier under the same light, find the closest color(s)

and then any decent graphics program will tell what that Pantone number equates to in the different formulae.

Or just tell me the numbers and I can do it.

[luv2fly]

2. I know there are android apps

Results vary based on quality of the original color (screen versus physical material).

[Orrex]

5. Worth looking into.

I'm concerned about getting good lighting. Most of the lights in my house give a piss-yellow shade to photos.

[Lochloosa]

3. Do you know any painters? They should have a ring of color samples.

This is not a color chart. A ring has several hundred colors.

If you don't know a painter try s Sherwin Williams store. They can help you.

[Orrex]

6. Nice!

Maybe I could deal myself a deck of color samples from the paint rack.

Quick--create a distraction while I grab a few hundred!


I may know a guy who has such a ring. He's a handyman and does a lot of paint contracting.

[ZZenith]

8. You would probably then need to go to that paint manufacturer's website

and download a “swatch” of their digital sample and then test that for its RGB ratios. Having the paint color number won’t tell you anything.

[Jirel]

9. Lots of scan devices out there match color.

Some even connect to your phone. From there it can be translated to hex, Pantone, RGB, etc.

[Ferrets are Cool]

10. If you have Photoshop, it is a very easy process

[mopinko]

13. yeah, i was gonna say that. the eyedropper tool

will give you the rgb, and the hex.

[Orrex]

14. Well, I don't know that it's that simple

When I've taken a pic of an object, or even a scan of an object's flat surface, there's wide variance from one pixel to the next to the next. What looks like a uniformly yellow surface might easily be a mix of olive, pure yellow, 100 different shades of yellow, and so on. If I use the eyedropper, I can wind up with any of those.

I'm not working from a recent version of Photoshop, but does a more current version (or Gimp) offer an "averaging" feature, whereby you can take samples from multiple points on an object and get the average color value?

[targetpractice]

22. You could do a Gaussian blur on the image first...

...That should smooth out the pixel by pixel variation.

Also, take a photo of your object in sunlight... ambient light affects the perceived color.

Obviously a spectrophotometer would be best, but this is a quick and dirty solution that I would at least try myself.

[Orrex]

24. Now that's a great nuts-and-bolts suggestion

Seems like the blur would do the job nicely!

[targetpractice]

25. Upon further reflection...

Select a representative portion of your object, maybe crop it out, and keep blurring until the process settles in on a color for most pixels.

I'm not at a computer to test my suggestions, but would love to know if they helped at all... Good luck.

[Jack Floto]

11. Use this website!

https://www.ginifab.com/feeds/pms/color_picker_from_image.php

You can upload the image to this site and then select the color from the image that you need identified. It'll give you the hex code, RGB code and CMYK code

[Orrex]

16. Thanks!

This might present the same issue that I described with Photoshop above, but it's definitely worth a look.

[Buckeye_Democrat]

12. We had devices to measure those values...

... when I worked quality control for a TV manufacturer, but I'm sure they were expensive as heck.

Colorimeters like this, but sturdier looking:
https://www.directindustry.com/prod/pce-instruments/product-37414-1477499.html

[Orrex]

15. That's really cool, though admittedly more sophisticated than I need

Thanks!

[csziggy]

17. Paint stores have devices that measure the color of samples

I don't know if they give the RGB values or are just set to give the color formula for mixing paint to match. You could call a paint store and ask.

Rather than take a photo of something you need to read the RGB values, scanning would give a more accurate image and therefore measurement since the scanner light and sensor are calibrated for accuracy - at least on good scanners . I know some Epson scanners can scan three dimensional items so that might even work with your objects. Of course, you would need to select the best lit section of the scan to sample.

As suggested, PhotoShop has an eyedropper tool that can tell you the RGB values of the place you sample. I do not know if some of the free PhotoShop knock offs such a GIMP has similar tools.

ETA - yes, GIMP does have a color picker tool and it can tell you the hex code for colors:

[Orrex]

20. I can check for a color sampler. We have several paint-matching stores around here

My ancient version of Photoshop has the eyedropper (as did the version of Paint Shop Pro that I used in the early 90s).

Thanks for the vid. I'm not very good with Gimp, though Photoshop and I go way back.

The problem, though, is that the dropper in either platform (as far as I can tell) takes a sample from one pixel, which is less than ideal for the reasons I described above.

I'd like the dropper to offer multiple sizes, averaging the color value across the sampled area. The programming for such a thing is far, far beyond me, but the math seems very simple.

[csziggy]

26. Newer versions of Photoshop will sample a larger area

I have PhotoShop CS6 (several years old) and it not only does point samples, it will take an average of an area with a radius of 101 pixels.

Just checked my older Photoshop books - version 5.5 offered only 3x3 and 5x5 sample areas - and the point sample.

[jmowreader]

18. Call around to the printing companies in your area

Ask them if they have an Xrite i1 spectrophotometer. If they do, take them the objects you want the colors read from. The device will return the CIELAB color values of the objects; from there they can use Photoshop to translate CIELAB to RGB.

[Orrex]

19. That's an amazing suggestion but honestly a little more high-end than is warrranted

As I mentioned, it's a very informal CAD project, not worth involving something with so man syllables.

Still, it's a great idea. I only wish that I were working on something worthy of it!

[jmowreader]

21. I used one to wrap a tournament bass boat

The angler wanted the boat to exactly match his truck. I used my i1 to scan many places on the truck, averaged, printed...the guy showed up and said he couldn’t believe we did it.

They are expensive; mine was $1500 and it was the cheap one. If you sell color like I do, you need one.

[Orrex]

23. Because you know it's all about that bass

You're definitely working at a higher level than I am, but it sounds like a really cool application.

[Buckeye_Democrat]

27. We used an Xrite at my last QC job!

I almost forgot about it because it wasn't needed too often at that particular job.

I bet a lot of companies have those kinds of devices in their QC labs.

[hunter]

28. I just ask my wife or daughter-in-law.

I suspect they are tetrachromats. According to them I can never get the colors right.

My wife can see a paint color she likes and select it in a paint shop, from memory, months or years later.

She's also a painter, watercolors and acrylics.

Even for those of us who are not tetrachromats, RGB does not describe the full range of human color vision.

My daughter-in-law is a computer guru who knows all the theory about why computers can never get the colors right. Part of her job is making sure colors on web pages are not ambiguous to most viewers, not like The Dress: https://en.wikipedia.org/wiki/The_dress

I learned some of this stuff when I still wanted to be a television engineer in the 'seventies. I knew very well NTSC television, which was fondly described as "Never The Same Color."

on edit: http://blogs.getty.edu/iris/a-day-in-the-life-of-a-digitization-expert/

My daughter-in-law does similar work. Get yourself a color card...

[flibbitygiblets]

30. That is really cool!

Welcome to DU.

[Orrex]

31. Holy moly that sounds awesome--I'll give it a try!

Thanks for resurrecting my question, and welcome to DU!