How to differentiate IS0 12647 vs FOGRA

[Gregg]

Hi, All.

It's been years since I've posted here.

My company has been running into more and more color issues between our Repro Houses (based in China) and our printers (also based in China).

Background (simplified):
Children's book publisher
Repro provides wet proofs (typically 2 rounds)
Once color is approved, files are released to printer

More and more, we are getting word from our printers that they cannot match the approved wet proofs.

Both Repro and Printer state that they are working to ISO 12647 standards. Printer often states Repro's ink densities are out of range.

Stock used for wet proofs is the same stock that is used for the final printing. Inks are (or at least should be) standard process inks.

Am I correct in thinking that if they are both using ISO 12647 standards, color should match, or at least be within tolerance between Repro and Printer?

How much would FOGRA profiling play a role in any shift (i.e. if Repro was outputting to 51 and Printer to 39)?

As you can imagine, language barrier can make it challenging to get down to the source of the issue.

Thanks in advance for any feedback.

Gregg

 

[Magnus59]

Technically a wet proof should be produced on the same press, same stock and same separations as the final printed product, at this stage any colour profiling should already have been applied as separations have already been completed. Ink densities should have been measured and recorded from the proofs and replicated for the final print run.

 

[SteveSuffRIT]

I thought the days of actual press proofs (Wet) were long gone, especially for commercial/book/magazine printers.
Can you share some measurements of Solid Ink Density (SID) and Tone Value Increase (TVI) of both proof and production?

 

[gordo]

Wet proofs are still used extensively in Asia - especially in China - typically for long run jobs like magazines, books, and packaging. They're often done on dedicated proofing presses rather than on the press that will do the actual final job. Note that the term "wet proof" is sometimes used to describe an inkjet proof since the ink is wet.
A close examination/comparison of the halftone dots should help distinguish the type of proof it is.

 

[Gregg]

The wet proof process, at this particular Repro House, is 2, 2-color presses. So CM are run first on press A, then KY on press B.

The main thing I am still trying to wrap my head around is how, in layman's terms, one could explain the difference between ISO 12647 and any FOGRA or GRACoL profile.

ISO 12647 is what every profile is based off of, is that correct?

 

[Kees]

Last time I had to work with wet proofs is 20 years ago, color matching was allways an issue, in my opinion because the wet proof was made on a proofing press (2 color) and the actual production was done on a 5 colour machine. On a proofing press you can obtain a better result, ink can dry better between printing 2 + 2 colors, speed and other variables. Printing proofs on the productions press would be the best practice but is also very costly.

 

[SteveSuffRIT]

The devil is in the details.
The now known facts that the "wet" press proof is done on 2 different presses, on 2 different passes, is important!
And it looks like the sequence is CM,KY, wet trap within pass, dry trap between pass.
Can you confirm production sequence (lay down order) is also different CMYK?

Yes, ISO12647 is the common base for both FOGRA & GRACoL.
But it is based on an all wet trap sequence (single pass) of CMYK.
In an earlier post, I was curious about SID & TVI values from both proof & production shts. Can you provide this info?

 

[Gregg]

Hi, Steve.

I'll need to ask the printer what their ink sequence is. The repro house recently switched to CMKY (from KCMY). They stated the change in sequence helped get closer to digital proofs output to FOGRA 52 standard.

Direct quote from Repro:
"While changing the ink sequence to C > M > K > Y, the color on uncoated paper wet proofs will get closer match to the Fogra 52 digital proofs"

The reasoning for the ink sequence change is something I haven't fully wrapped my head around. While we do print on uncoated (woodfree) stock for some titles, the majority of our titles are printed on coated matte art stock.

In regard to providing ink density and dot gain info, I'd have to query the repro house and printer. We do not have equipment to check those bars on the proofs provided to us.

 

[SteveSuffRIT]

Gregg,

You have mentioned 3 Fogra profiles for various paper:
#39 - Coated (older 2004)
#51 - Premium Coated (newer 2013)
#52 - #5 Uncoated

The paper surface smoothness, gloss, and holdout all effect the solid ink density (SID).
For example (approximate), Black ink on:
Gloss = 1.80
Matte = 1.50
Uncoated 1.25

 

[Gregg]

Not to get too far off topic, but another thing we are struggling with is whether or not to switch to FOGRA 51 & 52 (from 39 & 47).

We have surveyed all of our printers (in 2020 and again this year). Almost all them have stated their preferred profiles are 51 & 52, but then we have had some printers walk that statement back and say they have reverted to 39.

 

[Ozkan Hangisi]

I'll need to ask the printer what their ink sequence is. The repro house recently switched to CMKY (from KCMY). They stated the change in sequence helped get closer to digital proofs output to FOGRA 52 standard.

Hi Gregg,
If the wet proof and printing press have different ink sequences, the colors will not match.
The ink sequence shall be KCMY to match standard characterization data sets such as Fogra 39,47,51,52...

Am I correct in thinking that if they are both using ISO 12647 standards, color should match, or at least be within tolerance between Repro and Printer?

You are correct if all the process parameters are in tolerance with the same paper stock; the color should match.

How much would FOGRA profiling play a role in any shift (i.e. if Repro was outputting to 51 and Printer to 39)?

It is essential to use the same ICC profile for the color separation. Otherwise, the CMYK numbers differ after the conversion from RGB to CMYK. Theocratically, both Fogra 39 and 51 ICC profiles aim for the same Lab values during the conversion. But, in production, the color might look different on the paper with different CMYK values.

The main thing I am still trying to wrap my head around is how, in layman's terms, one could explain the difference between ISO 12647 and any FOGRA or GRACoL profile

PSO Uncoated ISO 12647 (ECI) ICC profile was generated using the Characterisation Data: FOGRA47L
ISO Coated V2 (ECI) ICC profile was generated using the Characterisation Data: FOGRA39
PSO Uncoated V3 ICC profile was generated using the Characterisation Data: FOGRA52
PSO Coated V3 ICC profile was generated using the Characterisation Data: FOGRA51
GRACoL2013_CRPC6 ICC profile was generated using the Characterisation Data: CGATS21-2-CRPC6.

The Characterisation Data includes icc test chart measurement results with an information text in the beginning.

Fogra and Gracol have different approach for the process control, but both aim to print with ISO 12467-2 compliance. For example, Fogra51 and Gracol CRPC6 ICC profiles were generated by measuring the ICC test charts printed according to ISO 12467-2:2013 standard. Even though the printing process approach differs for Fogra PSO and Gracol, the color deviation will be in tolerance for both printing results.

We have surveyed all of our printers (in 2020 and again this year). Almost all them have stated their preferred profiles are 51 & 52, but then we have had some printers walk that statement back and say they have reverted to 39.

While using the same stock for the proof and print, I would stick with Fogra39 and 47 M0 measurement mode. This is my personal choice after seeing some issues with M1 on the color seperation (slightly missing yellow) and proof, print visual match. The printing industry is still more used to with M0 mode.

 

[Xose1976]

Hi, All.

It's been years since I've posted here.

My company has been running into more and more color issues between our Repro Houses (based in China) and our printers (also based in China).

Background (simplified):
Children's book publisher
Repro provides wet proofs (typically 2 rounds)
Once color is approved, files are released to printer

More and more, we are getting word from our printers that they cannot match the approved wet proofs.

Both Repro and Printer state that they are working to ISO 12647 standards. Printer often states Repro's ink densities are out of range.

Stock used for wet proofs is the same stock that is used for the final printing. Inks are (or at least should be) standard process inks.

Am I correct in thinking that if they are both using ISO 12647 standards, color should match, or at least be within tolerance between Repro and Printer?

How much would FOGRA profiling play a role in any shift (i.e. if Repro was outputting to 51 and Printer to 39)?

As you can imagine, language barrier can make it challenging to get down to the source of the issue.

Thanks in advance for any feedback.

Gregg

IMHO your printers in Asia only use ink density as a measure, which in the past could be useful, but if color quality is your goal, you need a Spectrophotometer. The source profile (proof) must match the output profile, and the regulations must be clear. If your printer decides "not to update" to modern regulations, you will not have a solution. He is the typical printer who will have a paper with the densities attached to the side of the sheet control desk and that's it. To equalize densities, without taking into account many other factors, which could only be corrected with a modern machine with a spectrophotometer implementation. Attention to the whiteness of paper,