Is the paper white Lab a must?

[Dujo]

Hi all!

I have ran into a problem, where my customer wants me to print a testform, that has all values according to ISO12647-2.

The printing part is no problem, I can reach the desired Lab values for the colors, and the dot gain is in the tolerance for all colors, but the problem seems to be the paper white...

In the media standard, I see that the paper white according to ISO must be 95/0/-2 for PT1 and 94/0/-2 for PT2.
My paper is 96/1/-5 so as I see the b value is too much (in negative).
I can't find any tolerances for paper white in the media standard, and I just don't know if paper white is just a recommendation, or a must.
The paper importers, all said, that it is just a recommendation for reaching the right color and dot gain, but the customer is not convinced.

Can anyone help me with this issue? Am I missing something?
I have Heidelberg Color Toolbox, for measuring, and there, the maximum difference for paper white is
Delta L:3
Delta a: 2
Delta b: 2


Where are these values from?? is this the ISO 12647-2 requirement?

 

[rich apollo]

The values you cite are for paper measured on white backing, and are said to be informative. The normative values are 93, 0, -3 (PT1) and 92, 0, -3 (PT2) for paper measured on black backing. Normative values are necessary for compliance.

 

[Bloodsaler]

From my test,the paper white not effect the result much,but if your customer insist,you may look for help of your paper supplier.
I`m curious about where you located,the situation in my country is,almost all of the paper not match ISO tolerance~

 

[Dujo]

Thanks for the replies!
I am located in Hungary, and yeah, the situation is the same here, there are no papers that match the ISO tolerance. (its always the b value) I think it's because they use too much optical whiteners when producing the paper

 

[Bloodsaler]

Yes,the paper in my country often around 93,0,-5,also the b* value.You may be can think about use the device that got uv cut function~

 

[gordo]

Thanks for the replies!
I am located in Hungary, and yeah, the situation is the same here, there are no papers that match the ISO tolerance. (its always the b value) I think it's because they use too much optical whiteners when producing the paper

AFAIK there are no papers that match the ISO specification anywhere.

best, gordon p

 

[chevalier]

LOL how in the world was an ISO specification established for a thing that doesn't exist?

 

[gordo]

LOL how in the world was an ISO specification established for a thing that doesn't exist?

The answer is obvious - it's the wild and wacky printing industry. ;-)

Actually, I think that the problem came about because of a change, after the specifications were created, in how paper is manufactured. Today calcium carbonate is used as a filler in the basesheet and in the paper coating as a pigment. It provides brightness and a more blue-white shade than clay - the old filler - does.

There's more info here:

Quality In Print: Calcium carbonate - the problem with better quality paper

If I'm not mistaken, using a UV block filter in the spectro is not a solution because there are no standards for UV filters, nor the UV content of the light used by the spectro, nor the light under which you view the sample.

best, gordo

 

[Dujo]

Have you guys ever heard of "The Paperdam Group" ?
My paper supplier now sent me this
Paperdam Group - Expertise in Paper Performance

Basically they say, that you can achive ISO standard Lab values, and dot gain on any white paper, so it's no big deal if the paper Lab is according to ISO ro not....
But in the ISO standard, paper Lab is a normative, and there is a tolerance
Now I'm even more confused

 

[gordo]

Have you guys ever heard of "The Paperdam Group" ?
My paper supplier now sent me this
Paperdam Group - Expertise in Paper Performance

Basically they say, that you can achive ISO standard Lab values, and dot gain on any white paper, so it's no big deal if the paper Lab is according to ISO ro not....
But in the ISO standard, paper Lab is a normative, and there is a tolerance
Now I'm even more confused

Oh no. You're not confused enough

In the ISO standard, paper Lab is a normative, and there may be a tolerance - however there is no standard for how the deviation from the standard is measured nor is there a standard for the instrument's illuminant or geometry.

The Paperdam Group points out that, "as stated in ISO 12647-2 and -4 point 4.3, the most important issue is that the proof substrate matches with the production paper. The proof substrate should be specified, including parameters that are common in paper industry."

Unfortunately there are no published standards, specifications or trade customs in the paper industry. *The assignment of a particular grade to a quality category and the establishment of sales policies are made by each individual company. Also, the way that paper manufacturers measure and describe their papers is not the way that printers, or the ISO, do.

The technique described here:
Quality In Print: The issues of Optical Brightening Agents in paper and ink - part 5 of 5

might help.

best, gordo

 

[Dujo]

Thanks Gordo!

 

[Tarun Chopra]

If the client is difficult then make sure you get the paper white in tolerance as higher -b values could effect colours in highlight areas even though solids might be in tolerance, considering the fact that your customer reads media wedge (or some other custom control strip) to establish pass/ fail for overall print verification. Also there could be issues with establishing a visual match because of presence of OBA's in paper used on press and (high quality, where paper white is in tolerance) media used for digital proofing.

Regards

 

[schenkadere]

As if any of this nonsense matters in reality. I think customers and printers alike get pressured into thinking they need to comply with all this standardization. Amazing how such solid standards change so often. It's all relative...do i care if my box of Cheerios from Shop Rite doesn't look exactly the same as the one from Walgreens? Do I ever see them next to each other? It's all a bunch of hooey.

 

[J]

As if any of this nonsense matters in reality. I think customers and printers alike get pressured into thinking they need to comply with all this standardization. Amazing how such solid standards change so often. It's all relative...do i care if my box of Cheerios from Shop Rite doesn't look exactly the same as the one from Walgreens? Do I ever see them next to each other? It's all a bunch of hooey.

Rephrasing your thoughts to make them more relevant:

As if any of this nonsense matters in reality. I think customers and car manufacturers alike get pressured into thinking they need to comply with all this standardization. Amazing how such solid standards change so often. It's all relative...do i care if my Ford from Monday's assembly line doesn't match exactly the same as the one from Friday's? Do I ever test them next to each other? It's all a bunch of hooey.

J

 

[schenkadere]

Rephrasing your thoughts to make them more relevant:

As if any of this nonsense matters in reality. I think customers and car manufacturers alike get pressured into thinking they need to comply with all this standardization. Amazing how such solid standards change so often. It's all relative...do i care if my Ford from Monday's assembly line doesn't match exactly the same as the one from Friday's? Do I ever test them next to each other? It's all a bunch of hooey.

J

Cars carry lives...cars bring us to our source of income...cars parts and repairs are very expensive...big difference and an odd comparison to a cereal box stock color being a brightness of 92 vs. 93.

On a simpler note. If you look at a car to purchase and you like the car and the color...great...if same car is in a lot in a different state, yet the color doesn't exactly match yours, how does it matter? It's all relative...they told you it was sea foam green...you said, I like it...it's done.

I feel perfectly safe eating my breakfast cereal if the box color is out of tolerance a DeltaE of 4 compared to a standard that me, as a consumer, isn't even aware of.

 

[gordo]

As if any of this nonsense matters in reality. I think customers and printers alike get pressured into thinking they need to comply with all this standardization. Amazing how such solid standards change so often. It's all relative...do i care if my box of Cheerios from Shop Rite doesn't look exactly the same as the one from Walgreens? Do I ever see them next to each other? It's all a bunch of hooey.

There are certainly times when you see your Cheerio boxes beside one another where you can compare them - e.g. at Shop Rite. Interestingly most of Shop-Rite's own brand product labels are printed with FM screening in order to help maintain color consistency across product labels on the store shelves.

I've attended press tests at different times with representatives of companies like Kraft and Proctor & Gamble and asked them about their tolerance for color variation of their packaging. They told me that their tolerances are very narrow because, among other reasons, color variation can lead to some products being left on store shelves, can suggest to consumers that the specific product is not authentic, etc..

One can argue about what range of variation is tolerable and reasonable - but I don't think you can say that it's all a bunch of hooey.

best, gordo

 

[yannb]

Hello,

There are papers available that fall within ISO specs for paper white, we (Igepa) sell it. Omnisilk or Condat Gloss are just two, but since these paper names vary from country to country these may not ring a bell to you. Just ask your paper supplier and his competitors to send you samples of PT1 and PT2 of different weight. Be sure to measure on the right backing. Sheets of white paper are NOT good white backing. Try the white measurement board of an Eye One Pro or Eye One iO table. If I correctly white backing should have an L>92 and C<3.

To help convice your client that you're printing okay, add gray control wedges across the sheet. The ones from ECI are very good for visually checking ISO 12647-2 printing. See www.eci.org.

Regards,
Yann

 

[Stephen Marsh]

There are certainly times when you see your Cheerio boxes beside one another where you can compare them - e.g. at Shop Rite. Interestingly most of Shop-Rite's own brand product labels are printed with FM screening in order to help maintain color consistency across product labels on the store shelves.

Agreed, this is one reason why spot [brand] colours are used in packaging. The packaging world is very different to say commercial CMYK offset (even if the packaging product is being produced by offset instead of say flexo or gravure).

I've attended press tests at different times with representatives of companies like Kraft and Proctor & Gamble and asked them about their tolerance for color variation of their packaging. They told me that their tolerances are very narrow because, among other reasons, color variation can lead to some products being left on store shelves, can suggest to consumers that the specific product is not authentic, etc..

One can argue about what range of variation is tolerable and reasonable - but I don't think you can say that it's all a bunch of hooey.

best, gordo

I have worked as a finished art and prepress operator in creative/prepress studios that only do packaging. In my current position in an industry vendor, we specialise in providing Kodak and other solutions for packaging. The whole brand and product colour deal is a very big thing to the brand owners, which in turn becomes a big deal for the rest of the chain (design, prepress, printing).

Generally tolerances are more for spot colours than an ISO CMYK, and due to the variable nature of packaging substrate white points - ISO standards have not made as big an impact as found in the commercial CMYK offset world.

I also strongly agree with Gordo in that there are acceptable tolerances for colour and the devil in the detail is the agreement on what accounts as a reasonable expectation.

Stephen Marsh

 

[schenkadere]

There are certainly times when you see your Cheerio boxes beside one another where you can compare them - e.g. at Shop Rite. Interestingly most of Shop-Rite's own brand product labels are printed with FM screening in order to help maintain color consistency across product labels on the store shelves.

I've attended press tests at different times with representatives of companies like Kraft and Proctor & Gamble and asked them about their tolerance for color variation of their packaging. They told me that their tolerances are very narrow because, among other reasons, color variation can lead to some products being left on store shelves, can suggest to consumers that the specific product is not authentic, etc..

One can argue about what range of variation is tolerable and reasonable - but I don't think you can say that it's all a bunch of hooey.

best, gordo

I just like the word "hooey"...I needed an excuse to use it. My post sounded a bit to the extreme opposite...but I do feel a lot of it is hype and marketing...making companies jump through hoops because a customer was sold on some catch phrase or the flavor of the month. It's a tough enough business.

 

[schenkadere]

Agreed, this is one reason why spot [brand] colours are used in packaging. The packaging world is very different to say commercial CMYK offset (even if the packaging product is being produced by offset instead of say flexo or gravure).



I have worked as a finished art and prepress operator in creative/prepress studios that only do packaging. In my current position in an industry vendor, we specialise in providing Kodak and other solutions for packaging. The whole brand and product colour deal is a very big thing to the brand owners, which in turn becomes a big deal for the rest of the chain (design, prepress, printing).

Generally tolerances are more for spot colours than an ISO CMYK, and due to the variable nature of packaging substrate white points - ISO standards have not made as big an impact as found in the commercial CMYK offset world.

I also strongly agree with Gordo in that there are acceptable tolerances for colour and the devil in the detail is the agreement on what accounts as a reasonable expectation.

Stephen Marsh

Our board varies quite a bit...it's tough to find a consistent supplier.