Best way to specify color to print vendors?

[WharfRat]

2. LAB can be inconsistent, ...

Is this correct?
I thought LAB was universal and color shifts may occur when colors are changed to go to a specific device.

MSD

 

[Alith7]

Not sure why you undertake this task alone, as every supplier in the chain mentioned stands to benefit by not having to deal with a disenfranchised customer get them involved, and include your ink supplier in the discussion, you may find they can supply a limited batch of ink specific for this client and process to mitigate the different lab values of the substrates, all that you need to do then is run to density, print is all about putting an ink film on paper, a press does not create colour.

You haven't been in print long, have you?

 

[gordo]

2. LAB can be inconsistent, ...

Is this correct?
I thought LAB was universal and color shifts may occur when colors are changed to go to a specific device.

Lab values are universal but the instruments used to measure the values are variable. E.g. Inches and centimeters are universal but it's as if the rulers were made of rubber.

Gordo

 

[Deleted member 16349]

Lab values are universal but the instruments used to measure the values are variable. E.g. Inches and centimeters are universal but it's as if the rulers were made of rubber.

Gordo

Lab values are universal in principle but not in reality. There are some variations in how people see colour. Observer Metamerism.

Lab values comes from a mathematical model of how people perceive colour and was determined back around 1931 with a small sample group of people used in the testing. Hardly statistically valid when compared to the large number of people in the world and the variation of genetic characteristics.

I have read that Observer Metamerism is on the order of a DeltaE of 2. This is not too bad but it would be interesting to know if this was larger when taking into consideration more variations in people from around the world.

Also the colour science that has been developed works only under very restricted conditions that one does not normally encounter in everyday life. Two spots of the same colour can be in the same image and people will see them as being different colours. The perception of colours is affected by the surrounding colours and by the context of the image itself. The mind is fooled easily.

So I would say that Lab values are not universal but are the best option one has since colour does not exist in Nature and is only a perception in the mind.

 

[gordo]

Lab values comes from a mathematical model of how people perceive colour and was determined back around 1931 with a small sample group of people used in the testing. Hardly statistically valid when compared to the large number of people in the world and the variation of genetic characteristics.

Actually, the group of people tested were drunken male students on holiday from England in France. Given the nature of the print industry there is a certain validity to the research that was done.

ROTFL

Gordo

 

[rich apollo]

In all respect to Rich Apollo's comment "Is it enough to say the system doesn't work?"
I'll say it - IT DOES NOT WORK.

What's the alternative? What do you propose?

Our ink tech, pressroom manager & manufacturing manager all with over 25 years experience concur. LAB standards work some of the time. But we need it to work all of the time. (We are one facility of a large packaging company.)

And color management doesn't work. And G7 doesn't work. And bumblebees can't fly.

Specific colors, pastels and blues are particularly bad. I am of course talking infinitesimal differences in colors to the layman but, not to our print buyers

What kind of tolerances are we talking about? Is this something measurable, or is this a question of the pressmen skimping on the amount of luscious they pour into the ink fountains?

LAB may work fine for your customers after all THEY should be defining your level of quality. Anything more is a waste of money.

Oh yeah? Well, my customers can beat up your customers. So, there!

 

[Alith7]

all that you need to do then is run to density, print is all about putting an ink film on paper, a press does not create colour.

ok...this has been bugging me since last night. This comment. Right here. This is everything that is wrong with the print industry right now. People like this guy are making decisions. I don't even have words for how much this made the hairs on the back of my neck stand up. Make it everyone else's problem but yours. Then it's not your fault when things don't work right. URG!!

 

[Lukas Engqvist]

Secondary and tertiary colours at 100% is beyond control of prepress, so I do hope pressman (even if a dead press does not) takes responsibility for his/her part in creating (actually in press we block/filter out colour, not create it) colour.

CMYK values are only valid with an output intent. Spectral value would be great, but that is even more to manage, and I don't think we're there yet – so I guess Lab is what we are left with.

 

[Stephen Marsh]

Mmmm... Luscious


Stephen Marsh

 

[maas]

ok...this has been bugging me since last night. This comment. Right here. This is everything that is wrong with the print industry right now. People like this guy are making decisions. I don't even have words for how much this made the hairs on the back of my neck stand up. Make it everyone else's problem but yours. Then it's not your fault when things don't work right. URG!!

Maybe I should have elaborated, this is a business decision where we print to density and control our dotgain, our clients have our profiles and supply CMYK files, this is working well for us, if I was to have a discussion with a client on this subject and use some of the technical aspects to justify the outcome on press they would be lost, it keeps the relationship nice and simple where both clients and us as printers know where our responsibilities are and what the expectation is, Time magazine for example supply no proofs and insist their printers run to density, we have done so successfully for decades