Color constant inks

[tmiller_iluvprinting]

If Epson can produce a stable/color constant ink, why can't ink companies do the same for offset applications? We are constantly having to explain the reason for D50 lighting and the affects of metamerism outside of print standard lighting to customers who complain about "it doesn't match the proof in my office." This is getting old, you would think ink companies would address this to get a leg up on their competition.
Regards,
Todd

 

[inkedup]

Too many variables involved. Also, a lot of people don't understand colour or how ink and paper can react. I had one customer who rejected a job because the colour did not match his PMS guide. We asked him to bring this copy of the guide with him for the rerun. This guy shows up with his PMS guide, and I ask to see it to compare his guide to ours. He hands me this ratty looking guide from ( this is no lie ) 1986. We had just got new 2008 guides the month before. I brought him press sheets from his last run and showed him that the job that we ran matched our guide and then showed him the difference with his. He said that he didn't care that it matched our copy it didn't match his and he wanted a rerun. To make a long story short, our owner got involved and tried to work something out with him. He settled for a 15% discount and kept the 1st run. We no longer do business with this gentleman.

 

[gordo]

If Epson can produce a stable/color constant ink, why can't ink companies do the same for offset applications? We are constantly having to explain the reason for D50 lighting and the affects of metamerism outside of print standard lighting to customers who complain about "it doesn't match the proof in my office." This is getting old, you would think ink companies would address this to get a leg up on their competition.
Regards,
Todd

I'm not sure I agree with what you're saying. There is nothing the ink companies can do. Also, I could not find any reference to "color constant" on the Epson website so I don't know what that term means.
None of the inks used by Epson, or in presswork, are exact spectral matches to the media originally used to produce the original art. As a result, in printing, the inks used to create color reproductions are combined to simulate the proof (target artwork) only under one industry standard light source - referred to as "D50" or "D65". Proof and presswork form a metameric pair under those conditions.
What some shops do is to have a customer viewing area where presswork can be examined under different lighting conditions. Of course, when that is done, the proof is not available. I.e. compare proof and presswork under correct lighting - but examine presswork only under non-standard lighting.

best, gordon p

 

[gordo]

I had one customer who rejected a job because the colour did not match his PMS guide. We asked him to bring this copy of the guide with him for the rerun.

I think this is a preventable failure in communication - and I don't think the customer should be blamed. When a PMS/spot color is specified in the RFQ, I think it is prudent that the printshop confirm with the customer what the target color is for that spot color (i.e. my swatchbook, your swatchbook, an L*a*b* target, a previously printed sample, etc.). It takes just a few seconds for the sales rep or CSR to get clarity. The question can even be built into online RFQ systems.


best, gordon p

 

[Magnus]

If Epson can produce a stable/color constant ink, why can't ink companies do the same for offset applications? We are constantly having to explain the reason for D50 lighting and the affects of metamerism outside of print standard lighting to customers who complain about "it doesn't match the proof in my office." This is getting old, you would think ink companies would address this to get a leg up on their competition.
Regards,
Todd

Hi Todd, I agree with you! There must be ways to make offset ink less metamerism-sensitive. I dont even think theres any research on the subject. When I speak to a few different ink-suppliers none of them had any clue what I was talking about.

Dont think anyone thought that this would be possible with inkjet 10 years ago either.

Im looking forward to the new "K3 nanotech offset ink"!

 

[inkedup]

I think this is a preventable failure in communication. When a PMS/spot color is specified in the RFQ, I think it is prudent that the printshop confirm with the customer what the target color is for that spot color (i.e. my swatchbook, your swatchbook, an L*a*b* target, a previously printed sample, etc.). It takes just a few seconds for the sales rep or CSR to get clarity. The question can even be built into online RFQ systems.


best, gordon p

Our salesman brought in the order which asked for 4 colour process and one spot colour PMS Cool Gray # 11 on our house gloss text stock. Our ink company matched the colour and sent proofs and ink. Our salesman contacted the customer to have him sign off on the proofs, and was told to just run the job. We did and that's when the problem began. By the way, the proofs matched our PMS guide. Also we've heard from other printers in the Mississauga area that this fellow has pulled this stunt with other shops before.

 

[Bret Hesler]

I would be more interested in an inkjet ink using pigments that were similar to those used in litography. We did not have metamerism failure problems with pigment based dot proofs (thermal waterproof, finalproof or polaproof), like we have with inkjet proofs. I compared the spectral response curves of thermal waterproof and finalproof to our litho inks, and they were very close (I guess there is some chance of metameric failure, as they were not identical)

However, inkjet printers are made to produce the widest gamut of colors possible for pretty pictures, and certain manufacturers are quick to kill anything that will eat into their healthy ink profits. Has anyone seen anything coming off the latest inkjet presses, and able to comment on the colorants used?

Bret

 

[Cold]

There must be ways to make offset ink less metamerism-sensitive.

The sensitivity is not in the pigment used in an off-set ink nor in a dye colorant used in another application. The metameric effect comes in the difference between the two chemistries and there spectral responses to various light sources.

 

[tmiller_iluvprinting]

Gordon-
Color Constancy-is an example of subjective constancy and a feature of the human color perception system which ensures that the perceived color of objects remains relatively constant under varying illumination conditions.
I do not believe that the ink producers can't do anything about this. Epson did when they switched to the K3
inkset. Compare an image proofed on an Epson 9600 to the same image proofed on an Epson 9880 under
3200º lighting, especially a gray balance sensitive image and you will see what I am talking about.
I think Magnus said it best, bring on the K3 offset ink, or bring on the inkjet press!
Regards,
Todd

 

[gordo]

Gordon-
Color Constancy-is an example of subjective constancy and a feature of the human color perception system which ensures that the perceived color of objects remains relatively constant under varying illumination conditions.
I do not believe that the ink producers can't do anything about this. Epson did when they switched to the K3
inkset. Compare an image proofed on an Epson 9600 to the same image proofed on an Epson 9880 under
3200º lighting, especially a gray balance sensitive image and you will see what I am talking about.
I think Magnus said it best, bring on the K3 offset ink, or bring on the inkjet press!

Hi Todd, I'm very familiar with color constancy in human perception. However that is not what you wrote in your original post. You wrote: "Color constant inks - If Epson can produce a stable/color constant ink, why can't ink companies do the same for offset applications?" So, you wrote about inks and pigments (which is what I responded to) not human perception.
I am not in a position to "Compare an image proofed on an Epson 9600 to the same image proofed on an Epson 9880 under 3200º lighting" perhaps you can clarify what you mean and how you think ink manufacturers are failing to address an attribute of human vision.

thx, gordon p

 

[gordo]

At Todd,

I think I've figured out what you are trying to say - and it has nothing to do with color constancy but is related to the answer I posted earlier.

Let me rephrase your original question.

"If Epson can produce an ink for one of their printers that has a spectral response similar to offset inks, why can't other ink companies do the same? Or perhaps Epson extend that ink to their other printers used for offset proofing. That way we won't have to constantly to explain to customers the reason for D50 lighting and the effects of metamerism when they complain about "it doesn't match the proof in my office." You would think ink companies would address this to get a leg up on their competition.
Regards, Todd"

Is that sort of what you meant?

I believe that the spectral response of the pigments used in laminate proofs being similar to the spectral response of the pigments used in offset was a big selling feature and differentiator.
It would be interesting to hear from the proofing vendors why they can't or don't do this. Is it a technical barrier or just not worth the effort.
Maybe it's same reason that after some twenty years of ink jet usage they still dump their expensive output on the floor:

I guess they just don't care.

best, gordon p

 

[tmiller_iluvprinting]

Gordon-
When I move a printed press sheet from our pressroom standard D50 lighting to office lighting there is a perceptual change in the color of the imagery on the sheet. When I move an Epson proof produced with K3 inks from our pressroom standard D50 lighting to office lighting there is little perceptual change. When I move an Epson proof produced with pre-K3 inks from our pressroom standard D50 lighting to office lighting there is a significant perceptual change in the imagery on the sheet. Would I not be correct in stating that the Epson produced with K3 inks is more color constant(using the definition of said Color Constancy) than the press sheet or the Epson produced with pre-K3 inks. Epson clearly addressed this when they produced the K3 inkset,
and I am wondering why offset ink companies don't address this, or even attempt to address this. I know there are variables(UV brighteners, etc.) that also play a part, but I find it hard to believe that nothing can be done.
Regards,
Todd

 

[gordo]

Gordon-
When I move a printed press sheet from our pressroom standard D50 lighting to office lighting there is a perceptual change in the color of the imagery on the sheet. When I move an Epson proof produced with K3 inks from our pressroom standard D50 lighting to office lighting there is little perceptual change. When I move an Epson proof produced with pre-K3 inks from our pressroom standard D50 lighting to office lighting there is a significant perceptual change in the imagery on the sheet. Would I not be correct in stating that the Epson produced with K3 inks is more color constant(using the definition of said Color Constancy) than the press sheet or the Epson produced with pre-K3 inks. Epson clearly addressed this when they produced the K3 inkset,
and I am wondering why offset ink companies don't address this, or even attempt to address this. I know there are variables(UV brighteners, etc.) that also play a part, but I find it hard to believe that nothing can be done.
Regards,
Todd

No, I don't believe this has anything to do with "color constancy."
Color constancy is the eye/brain determining the approximate wavelength composition of light striking the observed object and then discounting that part of the illumination in order to obtain the "true" color of the object. Basically, a white paper looks white, or a red apple looks red, under a variety of lighting conditions.

What you're referring to is the effect of the spectral composition of K3 inks vs other inks. You are evaluating how one set of pigments reflect light compared to a different set of pigments under the same illuminant.
I.e. You're taking proof K3 and proof X and comparing them under illuminant D50 and under D32. One appears to shift more than the other. So what you are experiencing is illuminant metameric failure.

If you weren't making a comparison then you might be able to say that the color of the K3 proof does not appear to shift as you go from one illuminant to another. In that sense you might be able to say that color constancy is a factor in why the color doesn't appear to shift under different illuminants.

However when you are comparing, for example, two or more proofs to each other or to a press sheet you are in the realm of metameric pairs. If the proofing pigments were identical to the offset press pigments then you would expect a metameric match under every lighting condition. Since that's unlikely, then you would hope for them to be metameric pairs. I.e. match under one, or more, specific lighting conditions.

So, you're asking for inkjet manufacturers to use pigments that have a much closer spectral composition to the pigments use for presswork. That way proof and presswork would continue to match under different lighting conditions. That being said, the white paper of the proof and the white paper of the press sheet will always appear white because of color constancy.

Sorry if this is too pedantic.

best, gordon p

 

[tmiller_iluvprinting]

Gordon-
Pendanticism runs rampant in these forums, that much I have learned! =) In my last post I said nothing about comparing proof to proof, or proof to press sheet, what I did mention was how the perception of the imagery changed when moved under different lighting temps, and to what extent that perception changed.
Regards,
Todd

 

[Magnus]

So, you're asking for inkjet manufacturers to use pigments that have a much closer spectral composition to the pigments use for presswork. That way proof and presswork would continue to match under different lighting conditions.

No Gordo, He's asking for offset-ink that have a much closer spectral composition to the pigments in the K3 ink. That way proof and presswork would continue to match under different lighting conditions.

Maybe I misunderstood something or theres some irony going on here. But can't we all agree that K3 ink looks better in variated lightning than offset-ink? Less metamerism = better?

Original question: Is it possible to make offset-ink less metamerism sensitive?

(Sorry for the bad grammar, Im a swede.)

 

[gordo]

Gordon-
Pendanticism runs rampant in these forums, that much I have learned! =) In my last post I said nothing about comparing proof to proof, or proof to press sheet, what I did mention was how the perception of the imagery changed when moved under different lighting temps, and to what extent that perception changed.
Regards,
Todd

All righty then. Thank you.

gordon p

 

[gordo]

No Gordo, He's asking for offset-ink that have a much closer spectral composition to the pigments in the K3 ink. That way proof and presswork would continue to match under different lighting conditions.

Your grammar is excellent.

It would be interesting to hear from an ink manufacturer as to whether the pigments in inkjet printers can be formulated to be used for the press. But, if possible, wouldn't that mean that the ink would no longer conform to ISO? Would it not be better instead if the proofing inkjet pigments be similar to the pigments used in press inks? That way the press inks would still conform to ISO and the proof align with the press work under different lighting conditions.

best, gordon p

 

[Magnus]

It would be interesting to hear from an ink manufacturer as to whether the pigments in inkjet printers can be formulated to be used for the press. But, if possible, wouldn't that mean that the ink would no longer conform to ISO?

Well thats another question, but why shouldn't there still be an match to ISO? The color of the ink in 5000°k shouldn't be changed (in a perfect world). Maybe this isn't even close to be possible, but it would be interesting to hear what an offset ink manufacturer have to say about it indeed.

 

[Alois Senefelder]

Exact Colour !

Exact Colour !

Gentlemen and Magnus,


A PDF for "Fiat Lux" - I hope you will find it of interest and value.


Regards, Alois

 

[meddington]

Would it not be better instead if the proofing inkjet pigments be similar to the pigments used in press inks? That way the press inks would still conform to ISO and the proof align with the press work under different lighting conditions.

Wouldn't this then limit the ability to emulate spot colors or higher saturated printing? Not sure inkjet manufacturers see limiting the gamut to ISO as all that desirable given that the "proofing" market likely isn't as large as say the "photographic" market.