Industry standard spot color tolerance?

Ask or answer questions related to the flexo pressroom environment

Moderator: Frank Burgos

flexomonkey
Posts: 9
Joined: Tue Nov 20, 2018 1:55 pm

Industry standard spot color tolerance?

Post by flexomonkey »

Hi everyone!

What would the industry standard tolerance (delta E2000) be for a printed spot color for different production runs?

I was browsing the ISO 12647-6:2012 Part 6- Flexographic printing and I find conflicting information. One part says DE2000 of 6-
DE2000 6.JPG
DE2000 6.JPG (22.25 KiB) Viewed 6385 times
But if I take a look at the Table referenced, it mentions DE2000 1.5!
DE2000 1.5.JPG
DE2000 1.5.JPG (30.98 KiB) Viewed 6385 times
Does anybody know what is generally accepted?
Gory
Posts: 101
Joined: Fri Oct 17, 2014 10:08 am

Re: Industry standard spot color tolerance?

Post by Gory »

As I read it, that seems to specify no more than 1.5 from a standard, no more than 6 between different prints during a run, or different runs of the same job.

There is also the L:C ratio to consider.

I am not sure that I have ever encountered an 'industry standard'. Many customers set the spec at the high end/ high profile level. Many manufacturers set the spec they manufacture to if a customer does not specify one. For example, a perfume manufacturer is going to demand a much tighter tolerance than a customer who sells garbage bags. Coca Cola and McDonalds are very demanding for example, as their color is part of their brand identity.
flexomonkey
Posts: 9
Joined: Tue Nov 20, 2018 1:55 pm

Re: Industry standard spot color tolerance?

Post by flexomonkey »

Hi Gory,

Thanks so much for your response. Maybe I'm understanding incorrectly, but if you're always 1.5 DE2000 from your standard, how can you have a difference of 6 for different prints?

Would it be 1.5 for your starting point and then press variations can move you all the way to 6?
Gory
Posts: 101
Joined: Fri Oct 17, 2014 10:08 am

Re: Industry standard spot color tolerance?

Post by Gory »

It's a bit of a black art to me also. However, if you start up 1.5 clean and light, drift 1.5 from that, then next run you started up 1.5 dark and dirty, then drifted 1.5 from that, I believe you could get to a differential of 6.

Most of the industry - generally speaking - that I have encountered sets a DE spec of 2.0 from standard, and try to run within that window - you could still get a difference greater than that within a run (2.0 light v's 2.0 dark would be greater than 2.0 difference, but they would both be at 2.0 from standard)

I also try to use my eyes when something is running, and confirm data with a visual - sometimes a specrtophotometer will 'pass' a color that just looks too far from standard.
Frank Burgos
Site Admin
Posts: 1255
Joined: Wed Dec 31, 1969 8:00 pm
Location: North Carolina
Contact:

Re: Industry standard spot color tolerance?

Post by Frank Burgos »

I'm reading that the sample that you OK to run, the "OK print", must be within DE 6 of the specified target and that during the run the spot color should deviate no more than 1.5 during the run.
flexomonkey
Posts: 9
Joined: Tue Nov 20, 2018 1:55 pm

Re: Industry standard spot color tolerance?

Post by flexomonkey »

Gory, from your explanation I understand that each printed sample should be DE1.5 from our target, but since that 1.5 can move in any number of directions, if I measure print vs. print my DE could go up to 6. This makes sense to me.

Frank, from your explanation I understand that my first ok print should be within DE6 of my target, and I shouldn't deviate more than 1.5 during that run from that original ok print. This also makes sense to me.

I wonder what most people do?
Frank Burgos
Site Admin
Posts: 1255
Joined: Wed Dec 31, 1969 8:00 pm
Location: North Carolina
Contact:

Re: Industry standard spot color tolerance?

Post by Frank Burgos »

I think most people shoot for 2-3, unless compelled by an external force, like a customer, to hold to tighter and specific aims.

One client of mine prints for P&G. They demand, on a particular product, 2.5 for their logo spot color and 3.5 for their non-logo spot color. Don't recall the tolerance math. Maybe 2000
Frank Burgos
Site Admin
Posts: 1255
Joined: Wed Dec 31, 1969 8:00 pm
Location: North Carolina
Contact:

Re: Industry standard spot color tolerance?

Post by Frank Burgos »

I thought I’d cite a little bit of a case study, given the conversation.

In 2018 I led a project for a client to become GMI certified. GMI certification focuses on process control and documentation, equipment maintenance, training procedures, operator capability, and equipment performance. We did a Narrow web label flexo press and an HP Indigo digital press.

Under the guidelines, the color component of process control states:
“Color measurement of the spot color reference to the drawdown sample should not exceed ΔE2000 1.5 on white backing”
“Color measurement of the spot color reference to the press OK should not exceed ΔE2000 2.0 on white backing”

In addition:
Spot colors are held to ΔE2000 2.8
CMYK primaries are held to ΔE2000 3.5
CMY overprints are held to ΔE2000 3.5

There are other specifications and tolerances, but these are the relevant ones. They are, indeed, industry standards.

To become certified, we were held to ISO 12647-2, or offset standards, on a flexo press and a digital press. My colleagues and I were puzzled about this. It turns out that package suppliers may be insisting that flexo and offset folks print to the same aims. That makes sense, to me.

I was watching a color webinar and Steve Smiley was the speaker. He’s a highly knowledgeable color expert. In that presentation, he stated that very same thing; that package buyers are insisting on one standard. I don’t recall whether he mentioned flexo, offset and digital or just one technology.

Hope this helps. Sorry for not mentioning it earlier.
Frank
flexomonkey
Posts: 9
Joined: Tue Nov 20, 2018 1:55 pm

Re: Industry standard spot color tolerance?

Post by flexomonkey »

Hi Frank, thanks so much!!

We do have some customers who have defined specific tolerances, however other clients have asked us to go by ISO standards, which are still not quite clear to me!
Fuzz
Posts: 354
Joined: Mon Jan 19, 2009 4:37 pm

Re: Industry standard spot color tolerance?

Post by Fuzz »

Frank you say, They are, indeed, industry standards.

Where are these standards found? who created them?

Not bashing, I like these if they are indeed a accepted industry standard. Just wondering where they can be found, so I can relay to questioning customers.
Frank Burgos
Site Admin
Posts: 1255
Joined: Wed Dec 31, 1969 8:00 pm
Location: North Carolina
Contact:

Re: Industry standard spot color tolerance?

Post by Frank Burgos »

Hi Fuzz,

When a company goes through GMI certification, they gain access to a website with access to various resources, including guidelines. The guidelines point to relevant industry standards. For example, here are specs on color measurement conditions. Note the relevant industry ISO standards:

Color Measurement Conditions
Density Measurement is Status T, Absolute, in accordance with ISO 5-3:2009
Measurement geometry is 0/45, in accordance with ISO 13655:2009
Colorimetric observer standards is 2°, in accordance with ISO 13655:2009
Illuminate D50, in accordance with ISO 13655:2009
CIELAB color system, the color attributes are L*, a* and b*
Color difference formula: ΔE2000 Color Space kL* = 1 kC* = 1 kH* = 1, in accordance with ISO 13655:2009
Measurement Illumination Condition: M0, in accordance with ISO 13655:2009
Substrate white: L* = 94.00 a* = 0.00 b* = -2.00, in accordance with ISO 12647-2:2004 Amd. 1:2007
Substrate backing: L* = 94.00 a* = 0.00 b* = 0.00, in accordance with ISO 13655:2009

In addition, the are standards and the corresponding aims for TVI, grey balance, spot color, registration, trapping, and other stuff.

The following link takes you to a page on WhatTheyThink?, describing GMI certification. http://whattheythink.com/articles/75469 ... practices/

GMI has ties to certifications and memberships, including:
o G7
o IdeAlliance
o Flexographic Technical Association
o Printing industries of America
o Others
Frank Burgos
Site Admin
Posts: 1255
Joined: Wed Dec 31, 1969 8:00 pm
Location: North Carolina
Contact:

Re: Industry standard spot color tolerance?

Post by Frank Burgos »

If any of said customers needs help becoming certified, please feel free to have them contact me.
Frank Burgos
Site Admin
Posts: 1255
Joined: Wed Dec 31, 1969 8:00 pm
Location: North Carolina
Contact:

Re: Industry standard spot color tolerance?

Post by Frank Burgos »

Please note that the reference to 12647-2 is not mistake. We aimed for offset standards.
Fuzz
Posts: 354
Joined: Mon Jan 19, 2009 4:37 pm

Re: Industry standard spot color tolerance?

Post by Fuzz »

:smile: LOL....ISO would have satisfied me. Thanks for all the info and all you do!
Frank Burgos
Site Admin
Posts: 1255
Joined: Wed Dec 31, 1969 8:00 pm
Location: North Carolina
Contact:

Re: Industry standard spot color tolerance?

Post by Frank Burgos »

Bro. If you ask me what time it is, get ready to learn how to build a watch.
Post Reply