Digital BW, The Print

Hi,

would it theoretically be possible to develop a GLOP that could increase 
the DMAX of matte prints? After all, it's conlusively proven that 
various coatings can greatly enhance the DMAX of matte prints, but the 
stumbling block seems to be the methods for applying the coating. With 
GLOP in a cartridge this is no longer an issue. All we would need is a 
coating that could go into a cartridge without clogging the printer.

Is something like this possible?

--
Daniel Staver
http://daniel.staver.no

I asked this a while back, but no answers... Anyone?

--
Daniel Staver
http://daniel.staver.no


Daniel Staver wrote:

> Hi,
> 
> would it theoretically be possible to develop a GLOP that could increase 
> the DMAX of matte prints? After all, it's conlusively proven that 
> various coatings can greatly enhance the DMAX of matte prints, but the 
> stumbling block seems to be the methods for applying the coating. With 
> GLOP in a cartridge this is no longer an issue. All we would need is a 
> coating that could go into a cartridge without clogging the printer.
> 
> Is something like this possible?
> 
> --
> Daniel Staver
> http://daniel.staver.no

You mean a "matte optimizer?"  Hmmm, that would be a MOP <GGG>.

It almost seems contradictory.  The effect it would have on a velvet paper
would be to fill in texture (!?!?) wouldn't it?  Even to the point of adding
luster?

Seth 

==-----Original Message-----
==From: Daniel Staver [mailto:daniel@...] 
==> 
==> would it theoretically be possible to develop a GLOP that could 
==> increase the DMAX of matte prints? After all, it's 
==conlusively proven 
==> that various coatings can greatly enhance the DMAX of matte prints, 
==> but the stumbling block seems to be the methods for applying the 
==> coating. With GLOP in a cartridge this is no longer an 
==issue. All we 
==> would need is a coating that could go into a cartridge 
==without clogging the printer.
==>

Hi Daniel,

I have experimented quite extensively with various coating techniques
but GLOP I have never used though I have followed the threads on GLOP
with great interest.

My guess is the GLOP designed for glossy papers is made so that it can
be delivered through the printer ink delivery system so it has to be
very thin. This works great on glossy paper because it doesn't absorb
much of the liquid. But on matte paper ...

You can try creating IJC/OPM or QTR profiles using only the GLOP and
put on successive coatings with drying time in between.

In my coating approach which employs an airbrush I also have to apply
multiple coats to increase dmax. But I'm afraid you may find it takes
too many coats of GLOP to achieve the dmax of glossy papers. Why don't
you try this to find out if this is possible at all.

I was going to suggest you apply enough GLOP to seal the matte papers
then use a resin-based lacquer or Golden MSA spray on top to quickly
get the incredible dmax. But someone (Steve Kale?) found out that the
GLOP blisters horribly when touched by these sprays. This is not a
problem with the separation coating I use (Golden GAC 500).

I now have pretty much given up trying to coat matte papers to get
high dmax. What you end up with is a glossy surface which no longer
resembles the original fineart surface you want to preserve. Now I
coat just to protect the print. Now it turns out the "fogging"
technique suggested by Douglas Stockdale (in the Print spraying &
glazing thread) works incredibly well.

--nick

--- In DigitalBlackandWhiteThePrint@yahoogroups.com, Daniel Staver
<daniel@p...> wrote:

> I asked this a while back, but no answers... Anyone?
> 
> --
> Daniel Staver
> http://daniel.staver.no
> 
> 
> Daniel Staver wrote:
> > Hi,
> > 
> > would it theoretically be possible to develop a GLOP that could 
> > increase the DMAX of matte prints? After all, it's conlusively 
> > proven that various coatings can greatly enhance the DMAX of matte
> > prints, but the stumbling block seems to be the methods for 
> > applying the coating. With GLOP in a cartridge this is no longer 
> > an issue. All we would need is a coating that could go into a 
> > cartridge without clogging the printer.
> > 
> > Is something like this possible?
> > 
> > --
> > Daniel Staver
> > http://daniel.staver.no

Hi Nick,

Which version of the Golden MSA spray do you use, gloss, matte. etc.?

Thanks

Jules



--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "Nick H. Nugent" 
<nghin@p...> wrote:
> 
> Hi Daniel,
> 
> I have experimented quite extensively with various coating 
techniques
> but GLOP I have never used though I have followed the threads on 
GLOP
> with great interest.
> 
> My guess is the GLOP designed for glossy papers is made so that it 
can
> be delivered through the printer ink delivery system so it has to be
> very thin. This works great on glossy paper because it doesn't 
absorb
> much of the liquid. But on matte paper ...
> 
> You can try creating IJC/OPM or QTR profiles using only the GLOP and
> put on successive coatings with drying time in between.
> 
> In my coating approach which employs an airbrush I also have to 
apply
> multiple coats to increase dmax. But I'm afraid you may find it 
takes
> too many coats of GLOP to achieve the dmax of glossy papers. Why 
don't
> you try this to find out if this is possible at all.
> 
> I was going to suggest you apply enough GLOP to seal the matte 
papers
> then use a resin-based lacquer or Golden MSA spray on top to quickly
> get the incredible dmax. But someone (Steve Kale?) found out that 
the
> GLOP blisters horribly when touched by these sprays. This is not a
> problem with the separation coating I use (Golden GAC 500).
> 
> I now have pretty much given up trying to coat matte papers to get
> high dmax. What you end up with is a glossy surface which no longer
> resembles the original fineart surface you want to preserve. Now I
> coat just to protect the print. Now it turns out the "fogging"
> technique suggested by Douglas Stockdale (in the Print spraying &
> glazing thread) works incredibly well.
> 
> --nick
> 
> --- In DigitalBlackandWhiteThePrint@yahoogroups.com, Daniel Staver
> <daniel@p...> wrote:
> > I asked this a while back, but no answers... Anyone?
> > 
> > --
> > Daniel Staver
> > http://daniel.staver.no
> > 
> > 
> > Daniel Staver wrote:
> > > Hi,
> > > 
> > > would it theoretically be possible to develop a GLOP that could 
> > > increase the DMAX of matte prints? After all, it's conlusively 
> > > proven that various coatings can greatly enhance the DMAX of 
matte
> > > prints, but the stumbling block seems to be the methods for 
> > > applying the coating. With GLOP in a cartridge this is no 
longer 

> > > an issue. All we would need is a coating that could go into a 
> > > cartridge without clogging the printer.
> > > 
> > > Is something like this possible?
> > > 
> > > --
> > > Daniel Staver
> > > http://daniel.staver.no

Hi Jules,

I use the glossy aerosol can. However to really get a smooth invisible
coat on you'd need a water-based isolation layer. This layer helps the
MSA distribute evenly on the surface without soaking too much into the
absorbent inkjet receptive layer. I use an airbrush to apply the
Golden GAC 500 diluted with airbrush transparent extender. The
airbrush can apply an extremely fine layer of polymer which does an
excellent job in binding the fragile top layer.

At this point I still think the Lascaux is the easiest to use as you
can apply it directly. With the MSA you have to stop before a
reflection develops. The main goal is to apply the strongest coating
with very minimal changes to the print's surface. Using my technique I
can achieve a much tougher coating than Lascaux.

It took me a long time to come up with this coating approach to
preserve the beautiful surface of the Hahnemulhle William Turner
paper.

--nick

--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "lulalake_1999"
<lulalake_1999@y...> wrote:
> 
> Hi Nick,
> 
> Which version of the Golden MSA spray do you use, gloss, matte.
etc.?

> 
> Thanks
> 
> Jules

Daniel Staver wrote:

>
>>would it theoretically be possible to develop a GLOP that could increase 
>>the DMAX of matte prints? After all, it's conlusively proven that 
>>various coatings can greatly enhance the DMAX of matte prints, but the 
>>stumbling block seems to be the methods for applying the coating. With 
>>GLOP in a cartridge this is no longer an issue. All we would need is a 
>>coating that could go into a cartridge without clogging the printer.
>>
>>Is something like this possible?
>>    
>>
The only way to get matte prints darker is by using dye inks, with 
pigments you reach a point where the reflectance of the pigment particle 
surface stays equal whatever amount of ink is applied. And that 
reflectance is always higher then with black dye.  Black dye gets more 
Dmax because it doesn't reflect the light as even the black ink has 
transparency and the light penetrates the paper deeper and deeper while 
it is still surrounded by black dye, it is then only reflected when 
white paper is reached.  Scattered and what is left of the light it has 
to return to the surface again following the same path through the black 
dye.

Any Glop that increases the Dmax on matte papers will make it less matte 
too. Or that Glop has to have black dye in it and doesn't have to reach 
gloss status ;-)

Generations black has 25% dye in it, it is very black on matte papers 
but will fade in time to its pigment quality.

Maybe we are now at the start of a new rage in adding an extra ink 
channel with black dye that is laid down on top or underneath the 
pigment black in another ink channel :-)
I'm already getting quite close to Generations black on matte papers 
with Eboni so I'm not interested.

There's a new pigment for paints recently developed that has an 
extremely cracked surface, the cracks do something similar as the dyes, 
it is used to get total non reflecting surfaces for optical systems so 
will be used for cameras too. Have you ever seen the walls of 
laboratories that are used for sound experiments, wedge shaped foam 
maybe 30 cm deep sticked to the walls. Small frontal reflection and the 
angle of the wedge so steep that there's no sound reflected from that 
but reflected to the other wedge and so losing its energy till it hits 
the soft wall. That's how you drown sound and light.

An ideal paper coating for inkjet printing should create something 
similar, the ink shouldn't bleed sideways but should bleed inwards to 
create a small well where light can get drown or get filtered deeply by 
the color and return back preferably through that pipe again. Where no 
ink is, the white on the other hand should reflect as much as possible 
directly from the surface. Whether that is possible in one paper coating 
and have an acceptable angle of view is another matter. Gloss paper has  
a bit of that, you loose angle of view in return for more Dmax, the 
white is reflecting more directly, there's a kind of drowning happening 
at the black spots and what is reflected from there is scattered between 
the gloss surface sideways.

Ernst


Ernst

> The only way to get matte prints darker is by using dye inks, with 
> pigments you reach a point where the reflectance of the pigment particle 
> surface stays equal whatever amount of ink is applied. And that 
> reflectance is always higher then with black dye.  

I remember when QTR had that bug in 1440dpi mode where ink was literally 
poured out of the cartridge in big pools on the paper. The Eboni looked 
like shiny wax when the strength got too high. And at no point did the 
Dmax look higher than normal 100% Eboni.

> Black dye gets more 
> Dmax because it doesn't reflect the light as even the black ink has 
> transparency and the light penetrates the paper deeper and deeper while 
> it is still surrounded by black dye, it is then only reflected when 
> white paper is reached.  Scattered and what is left of the light it has 
> to return to the surface again following the same path through the black 
> dye.
 >
> Any Glop that increases the Dmax on matte papers will make it less matte 
> too. Or that Glop has to have black dye in it and doesn't have to reach 
> gloss status ;-)
> 
> Generations black has 25% dye in it, it is very black on matte papers 
> but will fade in time to its pigment quality.
> 
> Maybe we are now at the start of a new rage in adding an extra ink 
> channel with black dye that is laid down on top or underneath the 
> pigment black in another ink channel :-)
> I'm already getting quite close to Generations black on matte papers 
> with Eboni so I'm not interested.

I have some prints made with Generations black, and can't really see any 
visible increase in Dmax. Certainly nothing worth shortening the 
lifetime of the print over.

> There's a new pigment for paints recently developed that has an 
> extremely cracked surface, the cracks do something similar as the dyes, 
> it is used to get total non reflecting surfaces for optical systems so 
> will be used for cameras too. Have you ever seen the walls of 
> laboratories that are used for sound experiments, wedge shaped foam 
> maybe 30 cm deep sticked to the walls. Small frontal reflection and the 
> angle of the wedge so steep that there's no sound reflected from that 
> but reflected to the other wedge and so losing its energy till it hits 
> the soft wall. That's how you drown sound and light.
> 
> An ideal paper coating for inkjet printing should create something 
> similar, the ink shouldn't bleed sideways but should bleed inwards to 
> create a small well where light can get drown or get filtered deeply by 
> the color and return back preferably through that pipe again. Where no 
> ink is, the white on the other hand should reflect as much as possible 
> directly from the surface. Whether that is possible in one paper coating 
> and have an acceptable angle of view is another matter. Gloss paper has  
> a bit of that, you loose angle of view in return for more Dmax, the 
> white is reflecting more directly, there's a kind of drowning happening 
> at the black spots and what is reflected from there is scattered between 
> the gloss surface sideways.

Does all of this mean that a less glossy GLOP for glossy papers would 
also reduce the Dmax instead of increasing it? Sounds like there is an 
absolute link between glossiness and Dmax - Almost like a curse! :)

I guess what I'm after is either something to increase the Dmax of matte 
papers without sacrificing too much surface texture and adding too much 
gloss, or a GLOP for glossy papers which isn't as glossy as what we have 
today. Preferably something that rediced the gloss a bit rather than 
increasing it. I guess I just don't like high gloss prints.

--
Daniel Staver
http://daniel.staver.no

For that you simply need a better black ink - perhaps one with a smaller
pigment size so that the pigment to ink ratio increases.

> From: Daniel Staver <daniel@...>



> I guess what I'm after is either something to increase the Dmax of matte
> papers without sacrificing too much surface texture and adding too much
> gloss,

Nick,

Thanks so much for your reply and your sharing of this technique. I'm 
going to try this as I have airbrushes. I've used Lascaux and 
Printshield but this looks good.

Thanks again.

Jules


--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "Nick H. Nugent" 
<nghin@p...> wrote:
> 
> Hi Jules,
> 
> I use the glossy aerosol can. However to really get a smooth 
invisible
> coat on you'd need a water-based isolation layer. This layer helps 
the
> MSA distribute evenly on the surface without soaking too much into 
the
> absorbent inkjet receptive layer. I use an airbrush to apply the
> Golden GAC 500 diluted with airbrush transparent extender. The
> airbrush can apply an extremely fine layer of polymer which does an
> excellent job in binding the fragile top layer.
> 
> At this point I still think the Lascaux is the easiest to use as you
> can apply it directly. With the MSA you have to stop before a
> reflection develops. The main goal is to apply the strongest coating
> with very minimal changes to the print's surface. Using my 
technique I

> can achieve a much tougher coating than Lascaux.
> 
> It took me a long time to come up with this coating approach to
> preserve the beautiful surface of the Hahnemulhle William Turner
> paper.
> 
> --nick
> 
> --- In DigitalBlackandWhiteThePrint@yahoogroups.com, "lulalake_1999"
> <lulalake_1999@y...> wrote:
> > 
> > Hi Nick,
> > 
> > Which version of the Golden MSA spray do you use, gloss, matte.
> etc.?
> > 
> > Thanks
> > 
> > Jules

Daniel Staver wrote:

> >
> >>would it theoretically be possible to develop a GLOP that could increase
> >>the DMAX of matte prints? ...

The water-based coatings did this by making them glossy.  But, of course, we
lost the matte surface.  

Of interest, however, is that the dmax of these originally matte black inks
became very high.  As is also shown by the gloss loss with MIS PK on glossy
paper, as the gloss decreases, so does the dmax.  Then when they are
sprayed, the dmax returns.  

So, at least one major factor in dmax is simply how the light is reflected.
The total reflectance may be the same.  The angles at which the light is
reflected and where the viewer is makes the difference.  With a glossy
surface if one looks at the narrow angle of where that light is reflected,
the dmax is terrible.  With matte paper, that light is reflected evenly
everywhere, this lowers the dmax evenly regardless of which direction the
light is coming from.

Ernst wrote:

> ... Black dye gets more
> Dmax because it doesn't reflect the light as even the black ink has
> transparency and the light penetrates the paper deeper and deeper while
> it is still surrounded by black dye, it is then only reflected when
> white paper is reached.  Scattered and what is left of the light it has
> to return to the surface again following the same path through the black
> dye.

That's an interesting observation.  I had not considered the transparency
factor.  Some to consider the main difference between pigments and dyes to
be the transparency of the final colorant.  However, in my reading on water
color pigments, it appears that transparency is an independent variable that
is also a characteristic of some pigments.  So, while carbon is rather
opaque, other pigments have varying degrees of transparency.

Perhaps this explains how the cyan or blue pigments with relatively low
density actually increase the dmax of the carbon black inks.  If this is the
case, then what we may want is the darkest pigment over coating that has
high transparency.  Consistent with this, phthalocyanine (probably cyan
pigment) has relatively high transparency.



> I'm already getting quite close to Generations black on matte papers
> with Eboni so I'm not interested.

I agree.  Have you tried a dark cyan overcoat?



> 
> There's a new pigment for paints recently developed that has an
> extremely cracked surface, the cracks do something similar as the dyes,...

But wouldn't the cracks also let oxygen in and cause the fading to be
faster?


Paul
www.PaulRoark.com

Paul Roark wrote:

> 
>Daniel Staver wrote:
>
>  
>
> Ernst wrote:
>
>>... Black dye gets more
>>Dmax because it doesn't reflect the light as even the black ink has
>>transparency and the light penetrates the paper deeper and deeper while
>>it is still surrounded by black dye, it is then only reflected when
>>white paper is reached.  Scattered and what is left of the light it has
>>to return to the surface again following the same path through the black
>>dye.
>>    
>>
>
>That's an interesting observation.  I had not considered the transparency
>factor.  Some to consider the main difference between pigments and dyes to
>be the transparency of the final colorant.  However, in my reading on water
>color pigments, it appears that transparency is an independent variable that
>is also a characteristic of some pigments.  So, while carbon is rather
>opaque, other pigments have varying degrees of transparency.
>
>Perhaps this explains how the cyan or blue pigments with relatively low
>density actually increase the dmax of the carbon black inks.  If this is the
>case, then what we may want is the darkest pigment over coating that has
>high transparency.  Consistent with this, phthalocyanine (probably cyan
>pigment) has relatively high transparency.
>
>
>
>  
>
>>I'm already getting quite close to Generations black on matte papers
>>with Eboni so I'm not interested.
>>    
>>
>
>I agree.  Have you tried a dark cyan overcoat?
>  
>
I will try that. But an overcoat of cyan pigment on a black pigment 
layer isn't producing a black dye layer though.
One of my concerns with colored overcoatings is that they may increase 
metamerism. The Epson color head arrangement does something like that 
already with the KCMcmY order in undirectional mode, of course there's 
weaving done so it isn't Y totally on top and in bidirectional it is 
totally compensated. Getting a true overcoat in one printrun is not 
really possible.
In sikscreen color printing the color order can be varied for certain 
images, laying down yellow as the last color always gives a sheen on the 
CM(K) that I think will cause metamerism. But in that case it is a very 
pronounced thick layer on layer stack.

>
>
>  
>
>>There's a new pigment for paints recently developed that has an
>>extremely cracked surface, the cracks do something similar as the dyes,...
>>    
>>
>
>But wouldn't the cracks also let oxygen in and cause the fading to be
>faster?
>  
>
Any surface increase will result in extra gas-, humidity-, light- 
related fading. Not to mention staining by air pollution. But that's not 
different from micro porous coatings. But there are more Dmax effective 
micro textures than we have today.

The only way to achieve something like the above surface in inkjet 
printing is with a paper coating that has the same texture. The 
differences in Dmax of existing matte paper coatings with the same 
inkload show that there is more than just the inkload.

It wasn't actually a new pigment on its own but a surface coating 
system. Tried to find the original article (slashdot.org I believe) but 
failed so far. Found all kinds of interesting articles though and one on 
fungi in optical systems I was looking for some time ago but didn't find 
then :-)

Ernst

> It wasn't actually a new pigment on its own but a surface coating 
> system. Tried to find the original article (slashdot.org I believe) >
> but failed so far. Found all kinds of interesting articles though and
> one on fungi in optical systems I was looking for some time ago but
> didn't find then :-)

Are you thinking about this one?
http://www.newscientist.com/article.ns?id=dn3356
http://www.npl.co.uk/annualreview/2000/section1_2.html

--
Daniel Staver
http://daniel.staver.no

Jules,

-----------------------------------------
There are two ideas that started from this thread. I think mine kind
of went on a tangent and became a MOP (matte optimizer as someone
cleverly put  :)  . Still there are two ideas along MOP, one of
improving dmax, while this one that we are on is about print
protection with minimal loss of dmax.
-----------------------------------------

I'm sure you'll develop your own technique as you go along but here
are a couple things I've learned.

Don't overdo the initial GAC 500 application. You can use a piece of
clear acetate and hold your airbrush about 12 inches from it, brush
back and forth until you get a fine layer. This is how much you want
to get on your print.

After this the Golden MSA goes on very well. Again hold the can far
far enough away (12 in or more) so the print is just misted. And you
decide how much loss of dmax and how much gain in surface strength is
acceptable to you. 

I'd rather lose some dmax and get a print that can be pulled out from
a stack unscathed. For a smooth paper like Photo Rag you can achieve a
good level of protection with very thin applications (ie. minimal loss
of dmax) but for the William Turner I apply a bit thicker.

As as side note I find the Golden MSA yields a much stronger coat with
 very thin coating as compared to other sprays such as Grumbacher
Picture Varnish or Sureguard Lustre Lacquer. This maybe due to its
being more flexible than the others.

Good luck, and please do share if you discover other materials or
techniques that work better.

--nick

--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "lulalake_1999"
<lulalake_1999@y...> wrote:
> 
> Nick,
> 
> Thanks so much for your reply and your sharing of this technique.
I'm 

> going to try this as I have airbrushes. I've used Lascaux and 
> Printshield but this looks good.
> 
> Thanks again.
> 
> Jules

> >
> >  Have you tried a dark cyan overcoat?
> >

> I will try that. But an overcoat of cyan pigment on a black pigment
> layer isn't producing a black dye layer though.

True, it's not a dye.  But if it is truly transparent, then it relies on the
reflectance of the  underlying substrate -- usually paper.  Here, however,
that substrate is carbon.  So, its absorbency, the way a subtractive,
transparent color works, takes out only certain colors of the underlying,
reflective substrate.  Carbon is warm, so the cyan is absorbing the reds of
that warmth.  The cyan part of the carbon reflection will come right back
through, but there isn't much of that. 

I guess the question is, in part, how transparent the cyan really is.



> One of my concerns with colored overcoatings is that they may increase
> metamerism.

What I saw was so dark if there is some it's not of much consequence. 

Only one way to see.

Paul
www.PaulRoark.com

Now would we be better off printing with shades of white/grey ink on a black
service?  I guess the paper still has to be coloured black but this must be
easier to do in paper production rather than firing ink at it.

Nick,

Thanks again I'll take your advice.

Jules

--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "Nick H. Nugent" 
<nghin@p...> wrote:
> 
> Jules,
> 
> -----------------------------------------
> There are two ideas that started from this thread. I think mine kind
> of went on a tangent and became a MOP (matte optimizer as someone
> cleverly put  :)  . Still there are two ideas along MOP, one of
> improving dmax, while this one that we are on is about print
> protection with minimal loss of dmax.
> -----------------------------------------
> 
> I'm sure you'll develop your own technique as you go along but here
> are a couple things I've learned.
> 
> Don't overdo the initial GAC 500 application. You can use a piece of
> clear acetate and hold your airbrush about 12 inches from it, brush
> back and forth until you get a fine layer. This is how much you want
> to get on your print.
> 
> After this the Golden MSA goes on very well. Again hold the can far
> far enough away (12 in or more) so the print is just misted. And you
> decide how much loss of dmax and how much gain in surface strength 
is
> acceptable to you. 
> 
> I'd rather lose some dmax and get a print that can be pulled out 
from
> a stack unscathed. For a smooth paper like Photo Rag you can 
achieve a
> good level of protection with very thin applications (ie. minimal 
loss
> of dmax) but for the William Turner I apply a bit thicker.
> 
> As as side note I find the Golden MSA yields a much stronger coat 
with

>  very thin coating as compared to other sprays such as Grumbacher
> Picture Varnish or Sureguard Lustre Lacquer. This maybe due to its
> being more flexible than the others.
> 
> Good luck, and please do share if you discover other materials or
> techniques that work better.
> 
> --nick
> 
> --- In DigitalBlackandWhiteThePrint@yahoogroups.com, "lulalake_1999"
> <lulalake_1999@y...> wrote:
> > 
> > Nick,
> > 
> > Thanks so much for your reply and your sharing of this technique.
> I'm 
> > going to try this as I have airbrushes. I've used Lascaux and 
> > Printshield but this looks good.
> > 
> > Thanks again.
> > 
> > Jules

Daniel Staver wrote:

>>It wasn't actually a new pigment on its own but a surface coating 
>>system. Tried to find the original article (slashdot.org I believe) >
>>but failed so far. Found all kinds of interesting articles though and
>>one on fungi in optical systems I was looking for some time ago but
>>didn't find then :-)
>>    
>>
>
>Are you thinking about this one?
>http://www.newscientist.com/article.ns?id=dn3356
>http://www.npl.co.uk/annualreview/2000/section1_2.html
>
>  
>
Yes, that's the coating. The first link gives much better description 
than I remember of that process.

Ernst

> Yes, that's the coating. The first link gives much better description 
> than I remember of that process.

So when do you think I can use this stuff in my 2100? :)

"an object to be blackened is immersed for five hours in a solution of 
nickel sulphate and sodium hypophosphite. This produces a nickel and 
phosphorus coating containing between five and seven per cent 
phosphorus. Then the surface is etched with nitric acid to produce the 
super-black surface structure."

Doesn't sound very printer-compatible...

--
Daniel Staver
http://daniel.staver.no

Daniel Staver wrote:

>>Yes, that's the coating. The first link gives much better description 
>>than I remember of that process.
>>    
>>
>
>So when do you think I can use this stuff in my 2100? :)
>
>"an object to be blackened is immersed for five hours in a solution of 
>nickel sulphate and sodium hypophosphite. This produces a nickel and 
>phosphorus coating containing between five and seven per cent 
>phosphorus. Then the surface is etched with nitric acid to produce the 
>super-black surface structure."
>
>Doesn't sound very printer-compatible...
>
>--
>Daniel Staver
>http://daniel.staver.no
>
>  
>
I didn't write you could use it in your printer. At most a paper coating 
with a similar texture but being white could be produced. I also 
referred to the walls in sound laboratories, there's analogy between the 
surfaces.

On the black + cyan Paul discussed. In CMYK offset printing it is quite 
normal to print black text and have the cyan plate run the same text 
underneath but the characarters slightly trapped to cover up 
registration faults. But that offset black is very transparant and 
really needs a kick to get some Dmax.

Ernst

Paul Roark wrote:

>>> Have you tried a dark cyan overcoat?
>>>
>>>      
>>>
>
>  
>
>>I will try that. But an overcoat of cyan pigment on a black pigment
>>layer isn't producing a black dye layer though.
>>    
>>
>
>True, it's not a dye.  But if it is truly transparent, then it relies on the
>reflectance of the  underlying substrate -- usually paper.  Here, however,
>that substrate is carbon.  So, its absorbency, the way a subtractive,
>transparent color works, takes out only certain colors of the underlying,
>reflective substrate.  Carbon is warm, so the cyan is absorbing the reds of
>that warmth.  The cyan part of the carbon reflection will come right back
>through, but there isn't much of that. 
>
>I guess the question is, in part, how transparent the cyan really is.
>
>
>
>  
>
>>One of my concerns with colored overcoatings is that they may increase
>>metamerism.
>>    
>>
>
>What I saw was so dark if there is some it's not of much consequence. 
>
>Only one way to see.
>  
>
Paul,

No positive results.

I have printed some proofs with the Epson 10K, WasatchSoftRip, MIS 7600 
inks (including Eboni black) on HPR. Spectrocam Status T measurements.

The RIP was unlinearised, uncalibrated etc for this task, no need for 
that either. Straight CMYK fed it gives straight CMYK output. A square 
with strips descending  from 100% black, 99%, 94%, up to 66% black, next 
to one another. First two prints of that. Forced dried and after 30 
minutes a similar Cyan square printed on the black but 90 degrees 
turned. The other black square was over printed with the Light Cyan 
steps = 50% > 33% C.

The results, less visual blackness, a heavy magenta-aubergine sheen and 
a drop in Dmax of the best black strip (94%) from 1.747  to 1.54 for the 
100% cyan overcoat to 1.65 for the Lightest Cyan strip.

The other way around with Cyan first and black overcoat delivered a drop 
in Dmax of about 0.06 for the heaviest Cyan underlay and 0.02 for the 
lightest Cyan underlay. So no gain there either. Visually a bit bluer 
and lighter, which seems to increase in time, not much metamerism. I 
don't think I will measure them again, there's nothing to win there.

Given the weaving of the Epson head and the color print order the truth 
will be somewhere in between when this is done in one printrun.

This shows how much pigment inks reflect light. It may be different for 
another inkset.

There's one thing we didn't discuss on the differences between dye and 
pigment inks. The dye ink will be more transparent but still have more 
coloring power, I don't think one can put a too heavy load of dye in an 
inkjet ink, it will still print. With pigment inks we are at the edge of 
consistency in inkjet printing, pigment settling and piezo pump capacity 
etc considered. The coloring power of the dye will result in a darker 
coating from the top to the bottom. Less reflection than with pigments 
and heavier filtering inwards.

Ernst

Ernst,

What I did to find the best dmax was, in the IJC ink curves graph, have the
UC MK (when dealing with the OEM inkset) be a horizontal line at the level
of 250 of the 255 scale.  (In this case, more is darker.  This translates
into ink load 25 of a maximum 26 for that system.)  Then I ran the cyan
curve at a diagonal line from 0 to 255.  I printed a test strip for
linearization and inspected the output.  The best dmax with a clearly
descending density below it was at patch 4 of 26.  So, it took very little
cyan laid on top of wet UC MK to increase the dmax noticeably over what this
particular system was able to do with just UC MK.  The IJC dmax with just MK
was about the same as the Epson driver.  Perhaps other rips can do better
with just mk such that this approach is just not needed or effective.


Paul
www.PaulRoark.com 

> -----Original Message-----
> From: Ernst Dinkla [mailto:E.Dinkla@...]
> Sent: Friday, March 18, 2005 6:09 AM
> To: DigitalBlackandWhiteThePrint@yahoogroups.com
> Subject: [Digital BW] Cyan overcoat, Cyan underlay for Black... was Glop
> etc
> 
> 
> Paul Roark wrote:
> 
> >>> Have you tried a dark cyan overcoat?
> >>>
> >>>
> >>>
> >
> >
> >
> >>I will try that. But an overcoat of cyan pigment on a black pigment
> >>layer isn't producing a black dye layer though.
> >>
> >>
> >
> >True, it's not a dye.  But if it is truly transparent, then it relies on
> the
> >reflectance of the  underlying substrate -- usually paper.  Here,
> however,
> >that substrate is carbon.  So, its absorbency, the way a subtractive,
> >transparent color works, takes out only certain colors of the underlying,
> >reflective substrate.  Carbon is warm, so the cyan is absorbing the reds
> of
> >that warmth.  The cyan part of the carbon reflection will come right back
> >through, but there isn't much of that.
> >
> >I guess the question is, in part, how transparent the cyan really is.
> >
> >
> >
> >
> >
> >>One of my concerns with colored overcoatings is that they may increase
> >>metamerism.
> >>
> >>
> >
> >What I saw was so dark if there is some it's not of much consequence.
> >
> >Only one way to see.
> >
> >
> Paul,
> 
> No positive results.
> 
> I have printed some proofs with the Epson 10K, WasatchSoftRip, MIS 7600
> inks (including Eboni black) on HPR. Spectrocam Status T measurements.
> 
> The RIP was unlinearised, uncalibrated etc for this task, no need for
> that either. Straight CMYK fed it gives straight CMYK output. A square
> with strips descending  from 100% black, 99%, 94%, up to 66% black, next
> to one another. First two prints of that. Forced dried and after 30
> minutes a similar Cyan square printed on the black but 90 degrees
> turned. The other black square was over printed with the Light Cyan
> steps = 50% > 33% C.
> 
> The results, less visual blackness, a heavy magenta-aubergine sheen and
> a drop in Dmax of the best black strip (94%) from 1.747  to 1.54 for the
> 100% cyan overcoat to 1.65 for the Lightest Cyan strip.
> 
> The other way around with Cyan first and black overcoat delivered a drop
> in Dmax of about 0.06 for the heaviest Cyan underlay and 0.02 for the
> lightest Cyan underlay. So no gain there either. Visually a bit bluer
> and lighter, which seems to increase in time, not much metamerism. I
> don't think I will measure them again, there's nothing to win there.
> 
> Given the weaving of the Epson head and the color print order the truth
> will be somewhere in between when this is done in one printrun.
> 
> This shows how much pigment inks reflect light. It may be different for
> another inkset.
> 
> There's one thing we didn't discuss on the differences between dye and
> pigment inks. The dye ink will be more transparent but still have more
> coloring power, I don't think one can put a too heavy load of dye in an
> inkjet ink, it will still print. With pigment inks we are at the edge of
> consistency in inkjet printing, pigment settling and piezo pump capacity
> etc considered. The coloring power of the dye will result in a darker
> coating from the top to the bottom. Less reflection than with pigments
> and heavier filtering inwards.
> 
> Ernst
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
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