Hex or RGB to Pantone

[gwpriester]

Great link on the Pantone colors Mike.

[mwenz]

Oh. Regarding the swatches themselves. If one designs with Pantones and if/when the CMYK (or RGB) values are needed for output, generally the PDF creation can be used for the conversion. However, I would use Acrobat for the conversion as it uses LAB values for the conversion (I think). But choosing a profile in Xara that will not use Pantone and force the conversion can be used. But I would still check in Acrobat to be sure of the conversion.

Mike

[Rik]

Thanks very much for perceiveiring with this. Mike.

Can you tell me which CMYK values I should use?
Xara's or PhotoShop's?

I can use the same hex number and both products give me different CMYK values.

[mwenz]

Thanks very much for perceiveiring with this. Mike.

Can you tell me which CMYK values I should use?
Xara's or PhotoShop's?

I can use the same hex number and both products give me different CMYK values.

If you switch the Units in the Options dialog to 0-255, at least the RGB works correctly:



Xara will give the exact same number as PS does:



Without needing to start PS, what are the CMYK values it gives for the 2e2e2e hex number?

[Rik]

...what are the CMYK values it gives for the 2e2e2e hex number?

# 2e2e2e
PhotoShop gives: C: 70 M: 64 Y: 63 K: 63

I can't get anything like those numbers in Xara. Whether you've got 'Percent' or '0-255' selected.

[mwenz]

I am leaving in a couple minutes for a few days. I'll be taking the laptop and will take a look tonight when I get to where I am going...

[Rik]

Something else puzzles me, Mike.

The site you posted shows various colours.
I've captured a small portion, because I'm trying to find a Red in amongst all the colours.

So, if you look at the pic attached, a lot of those colours should not have the names that have been given.
How can they call that colour, Red?

[Albacore]

Hi Rik, why pantone, why not just use CMYK as Mike asked in post #3. It would save a lot of mucking about. The only real time that I would use Pantone colours is to save money on the set up cost for printing when I only need to use a few colours and the numbers of runs are large. If it is just for the colour matching as your unsure what your CMYK output is going to look like from Xara well that's fine go ahead and use Pantone. If you have access to a desktop laser printer try a print from that as it will give you a fair idea straight from Xara what your output will look like.
All printers that I have used in the UK have stated somewhere between 5000 to 6000 A4 size copies makes it worth while cost of using negatives for printing wither it is 3 or 4 colours used and to be honest most will go ahead and use 4 negs. because it saves time mixing a Pantone colour. If the number of copies are below this number then it will be a straight digital print just like your desktop laser but with better quality of output.

[JET]

My question would be; are my Pantone colour numbers correct.

Rik,

Apology in advance for any of the following which you may already know. This is a public forum, so it's assumed there are others reading, too.

Digital graphic designers (especially beginners in commercial print) commonly sweat blood over this due to some fundamental misconceptions:

Spot color:
The term "spot color" refers to specific physical substance (ink, paint, dye, or whatever) that is physically loaded into a printing press or some other repro mechanism. The color of the output, therefore, is simply a function of whatever ink is loaded into the press.

In offset printing, a spot color defined in the graphic program file is simply a command to print objects associated with that color to its own sheet (separation) as a grayscale image. There's no actual color mixing involved whatsoever. An ink of the specified spot color is simply loaded into the press. When you choose RGB, Lab, CMYK, Hexidecimal, HSB or whatever values for a spot color in graphics software, all you are doing is specifying how the separation named as the spot color will be represented on the screen (or when exported as a raster image or when changed to a process color, in which cases you're no longer dealing with spot color anyway).

For example, suppose you specify Pantone 185 (a red). You can simply define a spot color in the design software, name it "Pantone 185". You don't even have to select it from a "Pantone Library" provided with the software. You only need to define the color as a spot color. You can then set it to display any way you want on screen by "defining" its color. For example, suppose you set it to 50%Cyan 100% Yellow, a green. Doing that won't make one whit of difference in how it prints because, again, how it prints is simply a matter of the pressman physically loading the actual red-colored Pantone 185 ink into the press.

Process color:
Process color is a scheme for using a very small set of translucent physical pigments as "primary colors" which are "mixed" (actually, not mixed but printed on top of each other) in order to simulate the colors of more pigments, much like you learned in preschool to mix other colors from red, yellow, and blue crayons. This is very very far from perfect in standardized process inks, much as it is in crayons. Countless pigments exist in the physical world which simply cannot be accurately matched by using process color. (That's what people are talking about when they trot out the "gamut" buzzword.) That's one of the reasons why spot color inks exist in the first place. (It's not just a matter of reducing printing costs--in fact, spot colors are commonly used in combination with process color, thereby significantly and deliberately increasing the cost of a print job.)

To make matters worse, "color matching" is about more than just "color." For example, spot colors (being physical pigments) differ in opacity, whereas CMYK process inks are translucent in order to facilitate their "mixing." Then there are whole other matters of, for example, reflectivity and luminance. You can't accurately match a metalic or a flourescent spot color ink with CMYK even if your life depends upon it. Pantone can't even do that with its own metallic and flourescent inks.

And we're still not done. The exact color of the "whiteness" of the particular paper you print on significantly affects the appearance of offset inks (both spot and process), depending on the opacity of the inks involved.

And then there's the practical side of things. Pantone Libraries in mainstream software laughably specify CMYK "equivalents" in terms of hundredths of a percent. Really? I dare say there's not an offset press in the world that reliably and consistently holds ink coverage within a whole percentage variance; and the vast majority of real-world pressrooms probably vary several percentages.

Color models:

CMYK is a direct reference to the size of dots of four specific colors of actual ink. RGB, HSL, and even Lab are numerical values, but they are not direct references to pigments at all. HSL and Lab are color models; methods of representing perceived colors as a set of three values corresponding to "3 dimensional" axes of a conceptual "color space." RGB are just values to send to a CRT monitor's cathode gun or a flat panel monitor's LCDs, or to a printer's driver software. No one can control how much variance exists between all such devices (and many more) or how much individual devices change over time. That's where all the current hoopla and tedious gnashing of teeth and rending of garments over so-called color management (actually, device calibration) comes from.

Just because different kinds of measurements are numerically modeled doesn't necessarily mean they can be accurately converted between each other.

Converting RGB to CMYK is not a simple, unambiguous, mathematical 1:1 conversion like RGB to hexidecimal, which is just expressing the same set of three numbers in base 16 rather than base 10). There are up to four numbers in CMYK, whereas there are only three in RGB. So consider: How do you consistently "convert" three numbers into four? 2 x 2 x 5=20. So does 1x2x2x5. So does 2x2x2x2.5. So does 2 x 3 x 3 x 1.66....

In this sense, "converting" RGB to CMYK is an attempt to convert two entirely different things. Forget apples and oranges; how many apples equal one sheep?

Moreover, where do you see RGB? On a monitor. Where do you see CMYK? On a printed page. And what do you see them with? Human eyes. Monitors glow. Paper doesn't. Human vision (including color perception, contrast, detail) is constantly self-adjusting.

So the above sermon is just to make this point germane to your question: There is no single, precise, "conversion" of a so-called "Pantone color" to a CMYK mix, just as there is no single, precise "conversion" of an RGB value to a set of CMYK percentages. The spot-to-process values specified by Pantone--no matter how exactingly they were derived--are still mere recommendations, not actual colorimetric equivalents. And you are at liberty to make your best judgement regarding how "well" Pantone's (or anyone else's) recommendations serve as CMYK approximations. For example, Pantone's Spot-to-Process recommendation for Pantone 185 can specify 76.47% Y 'till the cows come home. But if I specify Pantone 185 as a client's spot color for his identity graphic when rendered in spot color, I'm still probably going to specifiy 100%Y in my process substitute in the client's style guide, if only for practical reasons.

And that's why you still buy printed Pantone swatch books, sign paint chip books, embroidery samples, vinyl samples, etc., etc., and make your own judgements. Don't strain at a gnat to swallow an elephant.

JET

[Rik]

Albacore: I have already said that I've never had to do this before.
Up to this point, all I've ever done is to design something on the screen. Then display it on the screen. Quite often through a projector as well.
From time to time, I've printed out some sheets on a home printer.

But, now I need to get things printed from a printer shop.
Some advice I've had is that I will need to supply Pantone Colours and/or CMYK values.

Hence asking advice from the Xperts on TG.

OK. It seems that I need to buy some swatches. Then is it a case of trying to see which colour closely matches what I'm looking at on my screen?
I just thought that there might a conversion, of one type to another?! To be able to give exact colour names/numbers. And not what the eye may be able to match or not.
Maybe not.

Jet: I am extremely grateful for you very detailed explanation. I think I will have to read it quite a few times. Many thanks indeed.