How can I identify color if I have only LAB coordinates? Is it possible to do it by using x rite spectrophotometer?

  • 2
    What do you mean by 'identify'? Are you trying to convert to another model? What software do you have access to? – Westside Nov 24 '16 at 7:29
  • I have to match a color for paint without having a physical standard, I have only LAB coordinates. We use x rite spectrophotometer when usually I scan a standard first and get the LAB coordinates and then I can match a color. – Milena Nov 24 '16 at 12:22
  • In that case, is the actual question how to manually enter Lab values into an X-Rite Spectro? – Westside Nov 24 '16 at 12:30
  • Exactly! This is the question – Milena Nov 24 '16 at 18:11

Yes... and no.

You have already a color... a Lab color.

Imagine you want to identify a speed, in terms of some scientific value, like a fraction of the speed of light. 1/1,000,000 e. You do have a speed.

Now you need to convert it into something a starship can handle. Probably it can, and that speed is let us say 90% of the speed of the spaceship.

But if you want to translate that into a horse running. It can not.

That is what out of gamut means.

Depending of what color is it, and what color profile you are using, you can translate that into that system... 90% of cyan? 60%? or out of gamut.

Some systems recompress and reinterprets the values.

"Oh. I can not reproduce all the colors, but I will try to do my best and, because I can not run at that speed, but the spaceship used its 90% speed, Me as a horse I will also run at my 90% capability and we will all be happy"

So there you have it... 90% horse speed... I mean color, so you have a dull color, not the original.

So yes, and no.

Based on your coment:

LAB coordinates and then I can match a color.

Match with what? A Pantone? A print for a magazine? Car paint? a Plastic? Cloth?

Xrite now owns Pantone, so there is a chance you need to match the data with a specific type of Pantone chip.

  • I have to make a formula for wall paint and I don't have a physical standard for color, only what I have that LAB coordinates, my question is how can I manually enter LAB values into an x rite spectrophotometer? – Milena Nov 25 '16 at 0:05

The simplest way to convert would be using Photoshops colour picker or Kuler

Entering in the LAB values these tools will automatically spit out the HEX/RGB/CMYK values.

Sorry not sure what you mean by identify.


Photoshop LAB Colours


Kuler LAB Colours

  • A caveat, worth mentioning, the color may be out fo gamut and the system may report it with some of the relative intnets instead so you wouldn't get the right color. And remember with un-calibrated monitors this is useless. – joojaa Nov 24 '16 at 10:41
  • 1
    So for example if you put the Lab value 100, 127, 127 Photoshop will report this as sRGB(255, 67, 0) But in fact it is NOT this color sRGB color of 255, 67, 0 is actually Lab(58, 70, 71) Which is not even near (100, 127,127) what one could NAIVELY expect. Might be worth noting this in the answer! sRGB(255, 67, 0) is just the closest color possible. – joojaa Nov 24 '16 at 10:51
  • I entered in 100,127,127 and get RGB 255,76,33 in Photoshop CC & RGB 255,70,0 on Kuler. I can only assume photoshop has better averaging algorithms, where kuler runs on the browser has a slightly simplified formula – Lex Nov 24 '16 at 11:35
  • no just different transformation intent – joojaa Nov 24 '16 at 13:50

I am attempting to do the very same thing, convert lab values of an absolute neutral gray 38,0,0 into a Sherman Williams paint.

I think for me the easiest solution is to print out a 5"x5" color swatch using Gracol color space on a Oris calibrated Epson 9000. Take it to Sherman Williams have them read it with their X-Rite device and call it a day. I will speak to the paint rep to see if he can input lab values, HEX, RGB, or anything else I can give him from a Photoshop calculation.

  • 1
    A paint representative is much better of with the LAB color. RGB, (hex is just a representation not a model) are device specific that is a RGB color is different on every monitor, which is not terribly useful for the paint maker. LAB on the otherhand is absolute, but you need to know what whitepoint and what standard observer the LAB is based on. – joojaa Mar 9 '17 at 7:08
  • Also since you print make sure your intent is made absolute colorimetric and check that it is not out of gamut. Also note that graphics design colorimeters typically measure what colors look like indoors, if this is for outdoor application you can be wildly off because of metamerism. – joojaa Mar 9 '17 at 7:16

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.