Paper whiteness

[HarveyDunn]

Hello, I'm a designer, looking for input on some questions so that I can do a better job of designing a color-critical project and getting it printed correctly.

Today's question: I assume that an ICC profile is premised on a certain color or whiteness of paper. So if I have a file that I know that I want printed using the GRACoL profile, and if I have found a printing company that says yes, they will print it useing the GRACoL profile, how do I check to confirm that the paper they are proposing to use is actually correct for the job?

And, while I am at it: how to check that the proof paper is also the same whiteness as that which is to be used for the job itself?

 

[gordo]

Follow this link to find the difference between paper whiteness and brightness - just to make sure that what you mean is what you wrote. It is the brightness that's most problematic.

The Print Guide: Understanding paper brightness and whiteness

Gordo

 

[HarveyDunn]

Thank you.

How do I double check that the paper the print shop are recommending for use in my project has the correct characteristics for the GRACoL profile?

 

[gordo]

Thank you.

How do I double check that the paper the print shop are recommending for use in my project has the correct characteristics for the GRACoL profile?

IMHO the whiteness of the paper, assuming a #1 coated paper is not an issue since our eyes auto-white balance. The issue that you may have is related to brightness. Most papers used for offset printing use optical brightening agents to make the paper appear bright. Most proofing papers do not include those OBAs. So the appearance of the press work compared wih the proof can disconnect quite dramatically under different lighting conditions i.e. lighting that contains different amounts of UV energy.
More info here:
http://the-print-guide.blogspot.ca/2009/03/issues-of-optical-brightening-agents-in.html

AFAIK, due to the OBA issue, no paper meets the ISO specified print condition that the GRACoL profile is based on.

Gordo

 

[Alith7]

We have been having a lot of problems with paper brightness lately in our shop. Mostly, it's been in matching something that was printed on a MUCH yellower sheet when everything now is so bright. Even the Grade 3 Papers have over 92 brightness mostly now.

IMHO, I have to disagree partly with you Gordo. Depending on the color that is critical, brightness of the papers can have a dramatic effect on color. Especially in dealing with screens or lighter colors.

Harvey~
if they are G7 compliant in their shop, there IS a "standard" for paper brightness, and, in order to pass G7 standards for calibration, it has to be within 2 DE (I believe) of the standard. At least, that is what our calibration software holds to.

With what Gordo recommended, talk to your printer and ask for a color accurate proof before printing. Generally an Epson. Most shops should be willing to give you one, though you will more than likely have to return it before printing the job. Ask them how accurate their proofs are, and if they see any concerns with the art that you are setting up. Generally, I prefer to know ahead of time if my customer has a specific color or look in mind so that I can check things over BEFORE they go into production to flag any problem areas. Also, keep in mind that "what you see on your screen" may not be color accurate, or may not be accurate to the profiles your printer is running. GRACOL and G7 are only guidelines, there is a wide gap within those guidelines that can make things look and print differently depending on dozens of variables, and they will still be "within spec".

Basically, there is no way to "guarantee" that their paper is within spec, your best bet is to communicate with your printer, let them know your expectations, and listen to their concerns. Like most things, good communication solves a lot of problems. hopefully that helps.

 

[gordo]

IMHO, I have to disagree partly with you Gordo. Depending on the color that is critical, brightness of the papers can have a dramatic effect on color. Especially in dealing with screens or lighter colors.

Actually, that's what I said - paper brightness will be where a problem is most likely to appear. You agree with me.

Best, gordo

 

[Alith7]

Actually, that's what I said - paper brightness will be where a problem is most likely to appear. You agree with me.

Best, gordo

oh. LOL
I misread that...so yes, I agree with the resident expert.