One way of knowing the correct color is to use the spectral data in pressSIGN 4 to be your master. It is the spectral data supplied by Pantone for their PMS, Goe, Plus Series and Hexachrome libraries.

Hi Ian, Aren´t these Pantone supplied values from a UV Cut SpectroEye? Your

Den 2. nov. 2010 kl. 09.50 skrev Ian Reid: > One way of knowing the correct color is to use the spectral data in

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Their current values are from 2003, Adobe updated the libraries in version CS3. For a new (2009) and unused solid coated swatch book, we at GMG have measured a mean of 2.0 DE 2000, the 95% quantile was at 5 DE 2000 (excluding fluorescent and metallic colors), using 4 measurements per sample with a Spectroscan with UV-cut filter, on white backing. I think Pantone used a Spectroeye for their values, so that should have been a fair comparison.

Have you also done comparisons with the new 'Plus' Series values published by Pantone with the 2009er Swatches: http://www.pantone.de/pages/Pantone/Pantone.aspx?pg=20721&ca=1

So basically you are telling me to just forget about accurate proofing when it comes to spot colors ;- ) Using the numbers sounds like the best idea. You say that the current version of CS uses a 2003 library and at the same time that it was updated in CS3 wich is not the current version. Or are you saying that they went back to 2003 books in CS5? The paperstock will be standarized to Igepa MAXI Gloss (aprox 96/1/-5). I see that the simulation of the ink tickness on a press is difficult in the production of the ink . Den 2. nov. 2010 kl. 10.16 skrev Hanno Hoffstadt: > Hi Lars, > > you would also have to use a paper stock that is the same or close to the paper used by Pantone. (What is "close" enough? a tough one...) > > And since there is no given standard ink thickness, the ink manufacturer would have to test-print a series of thicknesses and pick the closest point on the trace in CIELAB space (he'll be doing this anyway, but it probably should be fixed in your procedure, too). > > CIELAB reference numbers from Pantone have been measured with UV-cut filter (at least for solid coated / matte / uncoated). > > Their current values are from 2003, Adobe updated the libraries in version CS3. For a new (2009) and unused solid coated swatch book, we at GMG have measured a mean of 2.0 DE 2000, the 95% quantile was at 5 DE 2000 (excluding fluorescent and metallic colors), using 4 measurements per sample with a Spectroscan with UV-cut filter, on white backing. I think Pantone used a Spectroeye for their values, so that should have been a fair comparison. > > Just as you said, for some colors there may be a visual difference to the swatch book when proofing/certifying by Pantone's numbers. Your tolerance of DE (2000) < 2 will leave not enough room to match (within tolerance) swatch colors not only by numbers, but also visually. It's a dilemma, sure - and it's similar for HKS swatch books, by the way. > > Still, I would prefer to go by their numbers - unless you have a really representative swatch book collection and use a fixed device type with very good inter-instrument agreement for rolling your own reference numbers. But I doubt that one could narrow the tolerances down to DE 2, even with all this effort. In final production, the paper will be different and the printer will probably have to adjust the ink for this anyhow. (For example, when we printed 8 spot colours on two papers with very similar paper shade, but glossy vs. matte surface, we found that most solids could not be matched regardless of density settings: at closest point, there was a remaining color difference of up to 5-10 DE.) > > Best regards, > > Hanno > > > Am 02.11.2010 um 08:51 schrieb Lars Jacobsen: > >> Hi list-members, >> >> Trying to get my providers of Pantone inks to understand quality control, by simply measuring and reporting the product they sell so we can be assured that we get what we pay for. Sounds easy? Probably will be after spending hours together learning away basic color management. >> I´m trying to set up a solution, please give me som pros/cons: >> >> Measuring device: >> i1 Pro (recertified every year@Xrite) or SpectroEye. White Backing. >> >> Reference: >> Standard L*a*b from Pantone. Values from the latest Adobe CS? >> OR >> Providers, producer and end-costumer buys books from the manufactor. We measure that they are the same before we call it a reference. >> In theory the Standard values are probably the best way to go, but then we all know that the books also will be off from time to time. Can be difficult too explain, but at least we can stop meaning this and that and just let the numbers talk. >> >> Calculation method: >> dE 2000 >> OR >> dE1976? >> >> Tolerance for provider: >> dE 2 >> >> Visual control if needed: >> ISO 3664 (5000K/2000lx/MI C+) >> >> Documentation: >> Measurments are stored online for easy accsess for both producer and end costumer >> Certificate from Xrite >> >> >> Thanks, >> Lars