How do Pantone coated and uncoated colors relate?

Question

I need some help understanding the relationship between coated and uncoated Pantone colors.

From what I've read online, the coated formula (say 200 C) is for printing on coated (glossy) stock, and the uncoated variant (200 U) is for uncoated (non-glossy) stock.

This would lead me to believe that the colors are formulated to look as similar as possible when printed on their respective stocks.

However, they look quite different on my display, and when running them through the Pantone xref app targeting the TPX color book, it returns rather different results for each:

200 C => 19-1763 TPX
200 U => 17-1641 TPX

Is the difference between colors achievable on coated and uncoated stock severe enough to lead to this discrepancy? Or am I mistaken about the coated and uncoated colors being meant to produce the same results on their respective stocks?

When a color is referenced as simply Pantone 200, should this be construed to meant the coated or uncoated color?

Answer 1

You're pretty much spot on, they are formulated differently for the different papers. Uncoated is a more matte finish whereas coated is for glossier finishes, although in part that is down to coated paper being naturally more glossy. Additionally due to the lack of the steaming and pressing process, uncoated stock is by far more absorbent and requires the inks to be thinner and in lower quantities, however, in the vast majority of cases, the result will be almost identical. Its important to note that uncoated will obviously bleed more, by a margin of up to 10% extra, causing a shift in the print, especially with halftone printing, which will in turn affect the visible output.

In recent years however Pantone have skipped the U/C variants for the consumer market, and by default target uncoated variants. Some colours will look drastically different due to the difference in absorbency and whiteness of the paper, due to pantone white actually being transparent, to let the paper's whiteness show through.

In short, by default uncoated will be targeted, but if in doubt, contact your printers.

Answer 2

PANTONE+ Solid

Ink-wise, C = U

Pantone's PMS colours are based on specific physical ink formulations. The same mix of ink is used for a solid PMS colour in both C (on Coated paper) and U (on Uncoated paper) swatches for any named colour...

For example, PANTONE 021 C uses the same ink mix as PANTONE 021 U. (It's actually 100% PANTONE 021 Orange ink.)

The Coated or Uncoated versions of the books and colour palettes are there to indicate what the ink will look like once printed. Generally, ink on coated papers can be significantly more vivid.

Get your hands on the swatch books and check the colours.

Same ink, different result.

PANTONE+ Color Bridge

Beware of UP

However - this isn't the case for their Color Bridge swatches! These colours include a "P" (for four-colour Process) denominator eg PANTONE Orange 021 CP. CMYK process values are totally different between the coated and uncoated variants.

PANTONE 021 CP is very different to PANTONE 021 UP

• PANTONE Orange 021 CP (Coated paper, 4 colour process inks): 0c/65m/100y/0k
• PANTONE Orange 021 UP (Uncoated paper, 4 colour process inks): 0c/45m/86y/0k

I really don't know why Process Uncoated colours are significantly weaker ink mixes than Process Coated. Makes zero sense to me. Why would you reduce the ink when for uncoated substrates you need more to compensate for absorption? Does anybody know?

Different inks, very different results.

Unless you're mocking up an RGB visual and would like an approximation of poorly printed colours, or otherwise like the duller colours therein, avoid using Color Bridge Uncoated.

Below reference image from Pantone's x-ref tool https://www.pantone.com/color-intelligence/color-education/x-ref

Answer 3

The reason why your Pantone 200-Coated and 200-Uncoated get a different results when you convert them to a totally different Pantone chart is simple:

The C and the U on your Pantone chart are only previews of the final printed result.

Since you selected that color on a set of printed chips, the Pantone converter simply converts that PREVIEW to another TPX that looks close to it. You get different results because the 2 previews are different!

It's not an "ink to ink" conversion because that would be almost impossible (or way too expensive) to predict the final results on all the different surfaces/material/bases these colors can be used with. The TPX chart is a totally different palette that is more "general" than the one used in printing.

Your conversion should be right and it's normal it's different.

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Yes the C and U are meant to produce very similar results on different stocks but that color can be affected by other elements such as the color of the paper as well (e.g. ultra white or not.) or varnish. If you use your Pantone 200 on a dull uncoated vs Pantone 200 on a ultra bright white coated, they will look a bit different because the ink is not fully opaque and the color/brightness of the paper will influence the final result. Old paper can also be more yellowish, some uncoated dull are grayish, etc.

Unfortunately, it's not always possible to choose 2 Pantones that will look exactly the same on very different stocks. In general it's not worth using different Pantones to achieve the same result on different stocks; it's usually "good enough" to use the same Pantone on different stocks.

When someone says "Pantone 200", you look at your Pantone chart and check the coated or uncoated side depending on the stock you need to print on; coated/uncoated is for stock only, and the Pantone# is the ink. Printers won't tell you stuff like "I'll print with PMS200 U", they'll say "I'll print with PMS200" and will assume you'll look at the color book to get an idea/preview of the result.

It's up to you if you want to use C or U for your own layouts; on the plates at the print shop, it makes no difference unless you need to convert that Pantone to CMYK. The C and U are only previews for your own screen. If you need to convert to CMYK or RGB, and if you want brighter results, it's probably better to use the coated version. To my knowledge, using "uncoated" is not a standard, it's situational. I personally use coated by default even when I work on uncoated print job; I refer to my printed Pantone book for a preview, not my screen.

In general, in standard offset printing, the same ink is used to print a C or a U on coated and uncoated, unless you need something special such as a magnetic black for cheques or forms, or a fast drying ink for example. Printers can modify their recipes, use different bases/additives and often craft the Pantones themselves according to the Pantone guide.

To verify this, look at the recipe of the uncoated and coated Pantone your printer will probably use: They are the same.

Printing on uncoated stock generally requires more ink because the stock is more absorbent. If you have a look at ink sellers, you will notice their ink estimator will give you different results for the same quantity of prints; less ink for coated, more ink for uncoated.

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Related:

Printed Uncoated PMS on Coated Stock

About dot gain (absorption):

https://www.youtube.com/watch?v=O8hG0VIViNo