Hi Katlin,
I specify colors globally for a spirits company so this is a challenge I am very familiar with. The issue you are having is with Pantone. Pantone is sold as a color specifier and not good to use as a standard. Specifically there are three issues to overcome:
1.
Material: The colors are printed on optically brightened paper that has a ultra-violet dye that makes the color inherently brighter to the human eye and also shifts the colors slightly to the blue spectrum. The film that you are trying to print on likely does not have this element. (Sometimes UV varnish is added to trigger the application equipment, but I'm not going to cover that here)
2.
Pantone: All Pantone books and the colors within are a variable that need to be controlled. Last year at a printing conference I attended, a Pantone executive stated publicly that he hoped to get their books "under 3 delta-E" in the next few years coming out of the factory. Studies have shown that anything over a two is likely to be noticed by the consumer. In addition, the books change color as they age and they are expensive, so most printers that I work with don't update them yearly. What this means is that the color you are looking at is likely different than what the printer has. In addition, some pantone colors are outside the gamut of what can be achieved using normal ink pigments.
3.
The Printer: (I'm assuming you are a buyer and not the actual printer.) Discussing specific ink chemistry with the buyer is a obfuscation strategy that printers use to overwhelm buyers with technical details they themselves cannot solve. I'm also going to assume that this polyester film is being printed using flexography. If they are suggesting that water based ink isn't a technical solution because of adhesion issues, why bring that up at all?
So what can you do?
Expectations: Start with taking the pantone colors out of the equation by normalizing the colors to be achievable in the process you are working with and turn them into standard. This can be done by supplying the actual chip you are looking at to the supplier and having the supplier scan them with a modern spectrophotmeter like an X-rite exact. What you are going to want is to see the spectral "fingerprint" of the curve for the colors you are going to achieve and not just work with LAB values. If the printer doesn't have a modern spectrophometer in the ink room
and the press room or pushes back when this request is made then you are working with the wrong supplier. It is important that the device has the ability to read colors in "M1" which includes the UV spectrum into the data collected.
Also - Use dE2000 math. If the printer is just using LAB values to match colors then they aren't accounting for metamerism. Metamerism is where two colors look the same under one lighting condition, but not others. Make sure you and the printer are making observations in an ISO compliant light booth with D50 light bulbs. I have been to many plants where the light booths have old or even the wrong bulbs!
Second, have the printer / ink supplier show you what they are able to achieve on the polyester film to be printed with the comparison data that includes the spectral curves. They should be showing you a tint-ramp and the colors printed over white with the lowest L* (Whiteness) they are able to achieve if they are printing white on the job. What you are going to want to see is a curve that have a similar shape to the pantone reference color and aren't too "bumpy" or different.
When you achieve the closest spectral curve to the standard that is your normalized color. If its different than what you want, you will have to go off the pantone reference and develop a new color. You may need to manage expectations with the decision maker if it's not you. Remember, this film is not optically brightened paper
so they will be different than the book. If you have data then you will be able to see if they have achieved the bast match possible.
These new swatches and the data now become the color standards. Remember that the data is not going to change over time so the printer needs to lead with the data over time and not the physical chips which can fade over time. Once an agreement has been made make sure the printer is able to successfully get the ink from the ink room to the press. This is done by validating the printing again using the spectrophometer with the approved color data embedded in the device.
Hope this helps. I know someone who can help you with this task if you send me a private message I will connect you. All the best in luck with this!
Barry
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Barry Sanel CPP
Senior Graphics Services Manager
Diageo North America, Inc.
Norwalk CT
(203) 229-2145
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