Inky T O D - Sheen - What Is It? How Do I Get It?

[amberleadavis]

Some of the photos are too large so you have to give them time to load.

They should all be there... if not, let me know.

[amberleadavis]

Hypothesis - Paper alone is insufficient. For example, Yama-Budo sheened on some papers and not others. For that matter, sheeny ink alone is insufficient. (except maybe JHerbin 1670, I've always had that sheen).

 

http://sheismylawyer.com/She_Thinks_In_Ink/2014-Inklings/slides/2014-Ink_569.jpg

[amberleadavis]

Theory 2

 

It takes a camera to capture sheen.

 

Here is a scanned copy with a white background.

http://sheismylawyer.com/She_Thinks_In_Ink/2014-Inklings/slides/2014-Ink_559h.jpg

 

Here is a photo from my camera:

 

http://sheismylawyer.com/She_Thinks_In_Ink/Inked_Today/slides/20140605_142740.jpg

[amberleadavis]

http://sheismylawyer.com/She_Thinks_In_Ink/2014-Inklings/slides/2014-Ink_560.jpg

[terminal]

I wonder if what we're really talking about here is dichroism. That's the wikipedia link, but it's actually a fairly common measurement of inks used for screen printing(!). The idea is to measure how thick the "film" is that forms on top of the ink, and how much it changes the way think ink looks in different lights (of course, the point is to minimize this effect). For example, this is from a book called "The Printing Ink Manual" by R. H. Leach:

 

Dichroism

When assessing the color of an ink, it is important to standardize the application to minimize differences due to many factors, a very important one being film thickness. Apart from the obvious variation in apparent strength, film thickness also affects the hue. This change in hue with film thickness is called "dichroism".

 

This is from another book called "Pigments in Ink" by Dr. Joy Kunjappu:

 

 

"Control of physical characteristics of the organic pigments can have beneficial effects on the performance of ink. For example, phthalocyanine blue that can exist in (Greek alpha) and (Greek beta) crystalline forms exhibits blue and cyan (greener) shades, respectively. Thus the nature of stacking of the lattices has a role in the color generation.16 A consequence of stacking crystals is the anisotropic character exhibited by them. For example, beta copper phthalocyanine blue shows dichroism, exhibiting different colors when viewed in different angles. Anisotropy can also produce differential surface polarity within the crystal lattice. Thus brick-shaped crystals of beta form perform well in polar ink (as in alcohol-based packaging ink), and rod-shaped crystals of beta form perform well in low polarity ink (as in lithographic ink)."

 

So I guess what I'm saying is, if it's the "film" of these different chemical pigments causing the sheen, then getting them to show up requires a certain minimum thickness, the right angle, and in many cases, a paper with the right level of ink resistance / absorbancy to suck up the bulk of the medium?

[disillusion]

I wonder if what we're really talking about here is dichroism. That's the wikipedia link, but it's actually a fairly common measurement of inks used for screen printing(!). The idea is to measure how thick the "film" is that forms on top of the ink, and how much it changes the way think ink looks in different lights (of course, the point is to minimize this effect). For example, this is from a book called "The Printing Ink Manual" by R. H. Leach:

 

This is from another book called "Pigments in Ink" by Dr. Joy Kunjappu:

 

So I guess what I'm saying is, if it's the "film" of these different chemical pigments causing the sheen, then getting them to show up requires a certain minimum thickness, the right angle, and in many cases, a paper with the right level of ink resistance / absorbancy to suck up the bulk of the medium?

That sounds quite promising. Are insoluble pigments and dyes grouped as just pigments in screen printing? I am not familiar with the process. If we have a list of common dyes used in ink and their optical properties, we can work on something more definite. Do you know what sort of lengthscales at which dichroism usually occurs? If you have any sources that includes a bit more scientific data, please let me know. I will see if I can find Dr. Kunjappu's book in my library (too bad I don't have the unlimited access to scientific journals and books anymore) and make some sense of it.

 

Excellent place to start! Would they mind lending it for a little inky research? )

(see above) I was only half joking about the SEM, as I don't know what resolution is needed. I guess that most SEMs in labs would be in high demand so using it for non-research purposes would be quite difficult. Also they are quite fiddly and you really need to prepare good samples. As we only have a very primitive theory at this point, I highly doubt that we can accidentally produce samples good enough for us to determine what really is causing the sheen!

[terminal]

That sounds quite promising. Are insoluble pigments and dyes grouped as just pigments in screen printing? I am not familiar with the process. If we have a list of common dyes used in ink and their optical properties, we can work on something more definite. Do you know what sort of lengthscales at which dichroism usually occurs? If you have any sources that includes a bit more scientific data, please let me know. I will see if I can find Dr. Kunjappu's book in my library (too bad I don't have the unlimited access to scientific journals and books anymore) and make some sense of it.

 

I don't have anything more specific... I'll have to think about where I may have seen... or where I can look -- for more information on the actual pigment performance. Just out of curiosity, I tried to find more information just on "phthalocyanine blue". Here's the result:

http://www.scielo.cl/fbpe/img/jcchems/v55n3/art16_img09.JPG

The same article also has 8 other pigments:

 

http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-97072010000300016

 

You know, the other problem is that the ink manufacturers probable aren't going to be very interested in posting their recipes either....

[disillusion]

 

I don't have anything more specific... I'll have to think about where I may have seen... or where I can look -- for more information on the actual pigment performance. Just out of curiosity, I tried to find more information just on "phthalocyanine blue". Here's the result:

http://www.scielo.cl/fbpe/img/jcchems/v55n3/art16_img09.JPG

The same article also has 8 other pigments:

 

http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-97072010000300016

 

You know, the other problem is that the ink manufacturers probable aren't going to be very interested in posting their recipes either....

I think that article, while interesting, is not quite what we are looking for, as it is about using Raman spectroscopy to determine structure of these pigments. The radiation used is in the microwave region not visible light.

 

I found this related article which is a paper about generating realistic computer graphics of painted surfaces. The light scattering model is similar to what I had in mind when I made my first hypothesis, but without knowing the specifics of the properties of the dyes, we'll still be talking theory and nothing concrete. Also, looking at their generated images, I would say that the model is a little simplistic and needs a lot of refinement!

 

The ink recipes would of course be a secret, but if they are making commercial products that are highly likely to come into contact with skin, the chemicals used will have passed many safety tests and the physical/optical/toxicological data would be out there *somewhere*. If only there are some inky chemists among us with access to these databases, it would allow us to at least rule some possibilities out I think.

 

But perhaps the best approach to understanding would be to try and conduct some controlled experiments, instead of sitting here just talking about theory as I am doing

Edited June 7, 2014 by disillusion

[terminal]

What we need is an 'open source ink recipe' forum... but anyway. My gut is, like you say, do some controlled experiments, but perhaps even with single pigments. There are a whole bunch of single pigment ink recipes on the about.com chemistry articles... maybe the thing to do is just start there...

 

p.s. I love your Richard Feynman signature, disillusion

[WirsPlm]

What we need is an 'open source ink recipe' forum... but anyway. My gut is, like you say, do some controlled experiments, but perhaps even with single pigments. There are a whole bunch of single pigment ink recipes on the about.com chemistry articles... maybe the thing to do is just start there...

 

p.s. I love your Richard Feynman signature, disillusion

 

There have been several attempts at this (I think the latest is a wiki), currently all open source ink recipes and ink mixes go into the Inky Recipes subforum.

[amberleadavis]

So without dismissing the request for an inky open source thread....

 

Do we think Sheen is a FP term for dichoism.

[stephanos]

FWIW, try Diamine's Sargasso Sea, or Röhrer & Klingner's Alt-Goldgrün (old golden green)

[MCWB]

So without dismissing the request for an inky open source thread....

 

Do we think Sheen is a FP term for dichoism.

 

Yes, I think so. Specifically, that "sheen" is dichroism resulting from dye crystallisation when ink dries on the surface of paper, before it has a chance to soak in.

[amberleadavis]

 

Yes, I think so. Specifically, that "sheen" is dichroism resulting from dye crystallisation when ink dries on the surface of paper, before it has a chance to soak in.

 

Awesome!

 

So, how can I get it?

 

I think the answer is:

 

1. Buy ink that is a known sheener.

2. Use a wet writing pen.

3. Use paper that is slow to dry.

4. Capture the sheen with a camera because the scanner can't capture it.

 

Is this about right?

[dneal]

Awesome!

 

So, how can I get it?

 

I think the answer is:

 

1. Buy ink that is a known sheener.

2. Use a wet writing pen.

3. Use paper that is slow to dry.

4. Capture the sheen with a camera because the scanner can't capture it.

 

Is this about right?

The only thing I would change is the third one. Use paper that has little/low absorbency.

[amberleadavis]

OH.... can you clarify ... what is the difference? How could I tell?

[dneal]

'Use paper that is slow to dry' is vague. What you want is paper that doesn't soak up the ink quickly... i.e.: isn't very absorbent. That's the characteristic for what gets termed 'fountain pen friendly'. Rhodia, clairefontaine, etc... Since it's not soaking up the ink, the ink can pool somewhat and the film that leads to sheen is created.

[amberleadavis]

Thank you.

[disillusion]

What we need is an 'open source ink recipe' forum... but anyway. My gut is, like you say, do some controlled experiments, but perhaps even with single pigments. There are a whole bunch of single pigment ink recipes on the about.com chemistry articles... maybe the thing to do is just start there...

 

p.s. I love your Richard Feynman signature, disillusion

I have looked at the recipes and they seem simple enough. But I think I would start with some inexpensive Chinese ink that I have, playing with the concentration etc.

I also just realised that I could order food colouring, pigments, fabric dyes and even dangerous sounding basic dyes without leaving the desk! I might just try some of that later.

 

Feynman is cool and that quote is great, but very hard to follow. I try!

 

So without dismissing the request for an inky open source thread....

 

Do we think Sheen is a FP term for dichoism.

I think yes if you take dichroism to mean "showing two colours".

 

I looked up some common dyes and found that many of them show slightly different colours when dissolved in different solvents, or as a precipitate. Some also show drastic colour change when acidic/basic ingredients are added. E.g., disperse red 4 and solvent yellow 1.

[terminal]

'Use paper that is slow to dry' is vague. What you want is paper that doesn't soak up the ink quickly... i.e.: isn't very absorbent. That's the characteristic for what gets termed 'fountain pen friendly'. Rhodia, clairefontaine, etc... Since it's not soaking up the ink, the ink can pool somewhat and the film that leads to sheen is created.

 

It's interesting because it's not QUITE the same thing as paper the resists feathering... I know this because of the Buffalo Natur paper I experimented with a while back. It feathers like crazy and then takes forever to dry. But when the ink does dry, a lot of its components sit right on top of the paper. However, because of the paper wicking some of the components away, the sheen isn't as you'd expect...

 

 

I looked up some common dyes and found that many of them show slightly different colours when dissolved in different solvents, or as a precipitate. Some also show drastic colour change when acidic/basic ingredients are added. E.g., disperse red 4 and solvent yellow 1.

 

This also goes for the medium I assume... so we'd really have to test the pigments in the same medium and with the same other types of ingredients too.