Mixing dye and pigment inks

[ray]

I have seen cautions raised about mixing dye based and
pigment based inks. My canon i850 uses black pigmented
ink and dye based color ink. Both black and color ink
is used to print either color or gray scale pictures.
Support of these statements are in earlier posts on this
subject at the end of this article.

My understanding is that pigment inks are solids that are
finely ground (usually acrylics) mixed with an emulsifier
in a water based carrier. Dyes are salts dissolved in a water
base (aniline dyes?). From my woodworking experience, stains
can be either pigments or dyes. If the carrier is compatible
there is no problem mixing them, but you get a mess if you mix
oil based pigments with water based dyes.

Home use printers use water based inks. I don't understand
the problem in mixing dyes and pigments if they are water based.
I don't see any problem in using dyes in a printer designed for
pigments. I can see a problem in using pigments in a printhead
designed for dyes.

Why the caution about mixing dyes and pigments?




Ray R Jan 9, 12:29 pm show options


Subject: Re: Yet Another - Canon Ink Question

On the i850 for photo printing, black is a mixture of the three color inks.
The pigmented black is only used when a plain paper (text is assumed) mode
is selected.

An interesting hypothesis. One problem is that CY and M ink will not
produce black. It is not within its color gamut. The darkest color CYM
can produce is a dark muddy gray. To test the hypothesis I used
photoshop to print gray scale gradient from 0 to 100%. I looked at the
result under a microscope. Up to 80% gray it is composed of CY and M
dots to produce gray. Above 80% it is black dots to produce darker gray
and black. So at least on my i850 black ink is used to print dark
colors in photo mode. An examination of dark areas on a photograph
shows a mix of colored and black dots. This is true for either photo
mode or plain paper mode.


Now as to the type of ink the BCI3-eBK uses I emailed Canon. A received
an answer within hours even though it was Saturday. The issue of mixing
inks was ignored, but they stated that the black ink is pigmented and
the color ink is dye. Very good tech support from Canon.


My i850 produces very nice prints using Canon pigmented black or dye
based black ink. I can't see any difference. My conclusion is that on
the i850 using a mix of dye and pigmented ink is not a problem. Maybe
it is because of the small dot size that not much mixing takes place.

On the i850 photo black is not an option.

It is an option for me, but using dye ink does nor appear to give any
different results.

Perhaps the easiest
way to see it is to look directly at the print head carrier. There are slots
for only four tanks. The black (pigmented) tank is physically larger than
the three color tanks. Were you to use a photo black (dye based) ink,which
of the three colors would you remove - Cyan, Magenta or Yellow? I think what
may be confusing to you about the warning statement from the alotofthings
page is that while a number of Canon printers used BCI 3e tanks, only a very
few had the option to also use a separate photo ink print head. This is
where the potential for using the wrong ink could be present. If someone
refilled a photo black tank with pigmented ink, then not only would the inks
not mix properly on the sheet resulting in poor results, printhead damage
would also be likely.
The following is a copy from a posting by John Mills of WeInk. I found it by
doing a google search. I think he fully explains the i850 black ink issue.

=== start of copy ===============================
John Mills Jul 12 2003, 4:02 pm show options

Newsgroups: comp.periphs.printers

From: "John Mills" <[email protected]> - Find messages by this
author
Date: Sat, 12 Jul 2003 23:02:58 GMT
Local: Sat, Jul 12 2003 4:02 pm
Subject: Re: Ink consumption question for Canon i850 owners

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If you use the i850 in plain paper standard or High Resolution Paper
standard mode then all true black is handled by the black cartridge.
Any gray scale other than black is a mix of both black and colors.
Photos printed in plain paper standard mode or High Resolution Paper
standard mode also use the black cartridge for true black in the
photos, however what looks black to your eye may not be black to the
driver and any off black color will be a composite of the colors.
On all other modes the black is composited by the 3 colors.


Ron Cohen

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GB Jan 9, 5:04 pm show options

Newsgroups: comp.periphs.printers
From: "GB" <g...@dilithiumNO_SPAM.com.au> - Find messages by this author
Date: Mon, 10 Jan 2005 12:04:12 +1100
Local: Sun, Jan 9 2005 5:04 pm
Subject: Re: Yet Another - Canon Ink Question
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actually if you read the alotofthings url fully, which I have now, they go
one to explain why the 6BK is dye, not pigment as the Canon tables tries to
say it is. Basically the Canon table gets it wrong and another Canon
document gets it right...


However that doesn't change the fact that with my i865 I never fed more than
a dozen pages of plain paper or HR-101 through it, 99.99% of all its
printing was 6x4 photos. After printing a few hundred 6x4s the BCI-3eBK was
near empty (from brand new). So I really don't care what people try to say
about dye and pigment not mixing, and the 3eBK only being used for text etc,
you can't ignore what happens in front of your eyes.


Oh and exactly the same thing happened with my i850 before that.


"


news:[email protected]

 

[Arthur Entlich]

A few corrections. Pigments aren't acrylics if that was you were trying
to suggest. Many pigment inks use an water soluble acrylic resin to
help hold the pigment particles in suspension, however.

Pigment particles are usually mineral of some type or an insoluble
mineral salt. Carbon black is one used for black, for instance.

The incompatibility you speak of is more obvious with some special
inkjet coated papers. Pigment inks tent o sit on top of the surface of
the paper, while dye inks tend to penetrate them. The problem is the
black ink tends to sit on top and be fairly opaque and so if the other
inks are dyes, they end up lying beneath the black and get lost. In
some cases one of the other will not adhere to the paper being used.

Certain papers will not hold one of the other rink types well or won't
dry, or some bronze or texture the print only in the pigment area.

Art

 

[ray]

A few corrections. Pigments aren't acrylics if that was you were trying
to suggest. Many pigment inks use an water soluble acrylic resin to
help hold the pigment particles in suspension, however.

Pigment particles are usually mineral of some type or an insoluble
mineral salt. Carbon black is one used for black, for instance.

The incompatibility you speak of is more obvious with some special
inkjet coated papers. Pigment inks tent o sit on top of the surface of
the paper, while dye inks tend to penetrate them. The problem is the
black ink tends to sit on top and be fairly opaque and so if the other
inks are dyes, they end up lying beneath the black and get lost. In
some cases one of the other will not adhere to the paper being used.

Certain papers will not hold one of the other rink types well or won't
dry, or some bronze or texture the print only in the pigment area.

Art

Thanks for the clarification. I have seen the bronzing effect, but it
occurs with either dye or pigment ink. It is a function of the brand
of paper not being absorbent enough. My Canon i850 works well
with only a few brands of glossy paper. I have observed the ink
pooling on the surface with both the color as well as the black ink.
Are you saying if the ink does not pool on the surface there is no
compatibility problem? Do you know specifically what minerals
are used in pigment ink?

 

[Arthur Entlich]

Ink formulations vary considerably, especially in terms of drying times,
absorption, and so on. The paper coatings and bases can be extremely
complex. As you likely know, some of these papers are produced in the
same facilities are photo papers, because they require numerous coating
be layered on top of each other.

Once you are out of the manufacturer's recommendations, you are in
uncharted territory. Unless a 3rd party company indicates they have
tested and determined the inks you use will work with their papers, and
even then profiles for the inks may or may not exists, you just have to
experiment. There are no easy answers. In year gone by, I used to do a
lot of testing of new inkjet coatings. I discovered that some might
work well in a very limited driver profile, but "crash and burn" as soon
as the slightest change in amount of ink went down. Some papers work
well with heavy ink but poorly in lighter ink applications, more
commonly, they opposite case, where light ink applications work, but
heavy ink applications cause either a non-dry situation, or no
perceivable variation for the last 30% of ink coverage... it all looks
the same muddy black or brown. I found, for instance, that some papers
worked with one Epson ink formulation but not another (both dye).
Bronzing is yet another issue, sometimes caused by dichroic reflections
in darker inks, due to the component colors used to make black dye inks
dark enough.

Still another issue is how long the ink will survive on the paper. I
recall one brand of coated inkjet paper which, although looking quite
nice when the print came out of the printer, would begin fading within
weeks.

Regarding which pigments are used... hell, even if they would tell me, I
couldn't tell you. These are some of the most guarded secrets in ink
formulations. Some "standards" are known, but the holy grail of finding
pigments that fade slowly and evenly with their counterpart colors, have
a wide color gamut especially when ground very finely, don't cause
metamerism, and have other characteristics required for inkjet use, is a
science all to itself, and one that is closely guarded.

If you want to know more about pigment colorants, get a good book out of
the library or check Google about paint pigments, or go to your art
supply store and look at the tubes of color paints (water, acrylic or
oil), but as to which specific mixes inkjet companies and 3rd party ink
manufacturers are using... you'll likely need to hire some industrial
espionage agent to work for you ;-)

Art

 

[John Beardmore]

don't cause metamerism

What's that ?


Cheers, J/.

 

[Arthur Entlich]

From the colourware uk website: "Metamerism refers to the situation
where two colour samples appear to match under one condition but not
under another; the match is said to be conditional. Metamerism is
usually discussed in terms of two illuminants (illuminant metamerism)
whereby two samples may match under one illuminant but not under
another. Other types of metamerism include geometrical metamerism and
observer metamerism. Two samples that conditionally match are said to be
a metameric pair. If two samples have identical reflectance spectra then
they cannot be metameric - they are an unconditional match."

Here's a webiste about it:

http://akvis.com/en/articles/color-and-design/true-color-metamerism.php


Art