Digital BW, The Print

While I was consulting at Crane & Co. on Museo II I looked at a lot of
papers under strong, controlled UV illumination. The common OBs used in most
papers fluoresce under UV like you wouldn't believe. Dramatic difference
between the papers with and without (Museo papers have no Obs). Yes, they do
cause yellowing when they fade, but some fade faster than others. The other
significant concern is what this fluorescence does to prints viewed under
mixed light sources that contain a strong component of UV (such as
daylight). Can you say metamerism?

Rick Colson

Hello Rick,

>The other significant concern is what this fluorescence does to prints 
>viewed under mixed light sources that contain a strong component of UV 
>(such as daylight). Can you say metamerism?

Very interesting, first time I've heard of that.  I'd love to use a
non-OBA matte paper but unfortunately I've yet to find one that has as
good a dmax as HPR and VFA.  I've tested lots of papers and there's a
noticeable difference between these two and the others that I'm not
willing to give up.  There are some new ones I haven't tried yet. 
Does anyone know if any of them have as good a dmax?


Regards,
Clayton


Info on black and white digital printing at    
http://www.cjcom.net/digiprnarts.htm

On 04/01/2008 Clayton Jones wrote:
> Hello Rick,
> 
> >The other significant concern is what this fluorescence does to 
> prints
> >viewed under mixed light sources that contain a strong component of 
> UV
> >(such as daylight). Can you say metamerism?
> 
> Very interesting, first time I've heard of that. I'd love to use a
> non-OBA matte paper but unfortunately I've yet to find one that has as
> good a dmax as HPR and VFA. 

I missed the original, but the idea that OBA's cause metamerism is not 
right. If you use carbon inks on OBA paper, you do not suddenly get 
metamerism. Bromides containing OBA's did not display metamerism.

Metamerism is due to some ink pigments themselves reacting to UV with a 
degree of flourescence, causing a shift in the intensity and/or frequency 
of reflected light, and the image colours to change in an unbalanced 
manner. Such fluorescence can make it hard or impossible to adequately 
profile inks that have this behaviour, as the colour of the illuminant and 
amount of UV changes the image colour balance.

If you use metameric inks on papers containing OBA's you are going to make 
matters a little worse, but the real problem is the inks susceptibility to 
flourescence, not the OBA. They'll substantially do it anyway, even on 
papers without OBA's.

That is *the* issue with printing B&W using CMY pigments, and why 
metamerism is a problem with such inks to a greater or lesser degree. I 
have fairly recently gone from Generations G4 pigments to HP Vivera 
pigments, and the newer HP inks are vastly less metameric, OBA in the 
paper or not.

If you want to check the effects of OBA's, stick a sheet of 
perspex/plexiglass over the print. It blocks UV and you'll see the paper 
and inks unaffected by flourescence of either OBA's or pigments.

You are not going to find papers without OBA's that match papers with 
OBA's for white/brightness/contrast, it's an oxymoron. Paper fibres, no 
matter how pure, just aren't very white. Baryta coating is as white as it 
gets without introducing flourescing OBA's to convert UV into visible light.

The biggest problem with OBA's IMO is that they fade eventually. I have 
some Photo Rag inkjets from 2003 that have sat in striplight and daylight 
24/7, completely unprotected, and the base has turned about the same 
colour as white chocolate. The G4 inks have held up very well.
-- 
Regards

Tony Sleep
http://tonysleep.co.uk

At 03:04 PM Friday 1/4/2008, you wrote:
>I'd love to use a
>non-OBA matte paper but unfortunately I've yet to find one that has as
>good a dmax as HPR and VFA. I've tested lots of papers and there's a
>noticeable difference between these two and the others that I'm not
>willing to give up. There are some new ones I haven't tried yet. 
>Does anyone know if any of them have as good a dmax?

Entrada Natural is pretty good.

I might add that initially I had a really bad flaking problem with Entrada, but then with a hake brush and a cyclone blower bulb, fixed the problem ... but then yesterday I had more prints that flaked than didn't, even with the brush routine. Don't know what the story is there ... I love everything about the paper except for this occasional problem. I love the slight texture of the Entrada more than the smooth Hot Press papers - it resembles PhotoRag's texture very closely, but with a more cream OBA-free colour ... and douible-sided. It's strange that I can go through a box with no problems and then strike a bad patch of flaking. 

Richard 
--
Backroads Essay:
http://picasaweb.google.com/rsmallfield/TheBackroadsOfWarkworth
Greeting Cards available for purchase:
http://picasaweb.google.com/rsmallfield/GreetingCards
http://photos.smallfield.vze.com
http://smallfield.vze.com

   "We dissect nature along lines laid down by our native language. 
   Language is not simply a reporting device for experience but a 
   defining framework for it."
   --Benjamin Whorf

Hi Clayton:

Over the years I've seen and tested a few hundred "fine-art" matte  
and watercolor papers, and I think Hahnemuhle Museum Etching is a  
good contender as a non-OBA paper. It has as good a Dmax visually as  
any matte paper I've seen, it feels incredibly nice in the hand (it's  
350gsm and feels more like 400gsm to me compared with most 300gsm  
papers) and is great when matted in large sizes because it sits so  
flat. It also doesn't come across as being too warm in color to me,  
though the base is definitely not bright white either. It also does  
not flake or scuff as easily as many other papers in its class with  
all the pigment inks I've used with it.

All the best,

Andrew
---------------------------------------------------
Andrew Darlow
Editor, The Imaging Buffet
http://www.imagingbuffet.com
Author, 301 Inkjet Tips and Techniques:
An Essential Printing Resource for Photographers - http:// 
www.inkjettips.com



On Jan 3, 2008, at 9:04 PM, Clayton Jones wrote:

> Hello Rick,
>
> >The other significant concern is what this fluorescence does to  
> prints
> >viewed under mixed light sources that contain a strong component  
> of UV
> >(such as daylight). Can you say metamerism?
>
> Very interesting, first time I've heard of that. I'd love to use a
> non-OBA matte paper but unfortunately I've yet to find one that has as
> good a dmax as HPR and VFA. I've tested lots of papers and there's a
> noticeable difference between these two and the others that I'm not
> willing to give up. There are some new ones I haven't tried yet.
> Does anyone know if any of them have as good a dmax?
>
> Regards,
> Clayton
>
> Info on black and white digital printing at
> http://www.cjcom.net/digiprnarts.htm
>
>






[Non-text portions of this message have been removed]

Hi Richard,


"It's
strange that I can go through a box with no problems and then strike a 
bad patch
of flaking."

Have you ruled out the possibility of dust settling on to the paper 
surface from your end? 

Possibly a work area problem...? Just a thought.

Scott

As an aside, I just read this on a website: 

"Velvet Fine Art Paper - With a base that is 100% cotton rag, buffered and acid free, this paper is coated with the Enhanced Matte coating, giving exceptional color gamut and high D-Max. The velvet surface offers a unique museum quality feel."

I hadn't realised that EEM and VFA had the same coating.

Richard
--
Backroads Essay:
http://picasaweb.google.com/rsmallfield/TheBackroadsOfWarkworth
Greeting Cards available for purchase:
http://picasaweb.google.com/rsmallfield/GreetingCards
http://photos.smallfield.vze.com
http://smallfield.vze.com

   "Good name in man and woman, dear my lord, 
   Is the immediate jewel of their souls:
   Who steals my purse steals trash...
   But he that filches from me my good name
   Robs me of that which not enriches him,
   And makes me poor indeed.
   --Shakespeare, Othello, III:3

> Possibly a work area problem...? Just a thought.
> 
> Scott
>


That's my experience. It's especially important to keep unused paper
in the plastic bag. As well, paper edges abrade, producing dust when
heavy papers are removed from packages. I think a t-shirt or
compressed gas can is more effective than brush or squeeze-bulb.

Tony Sleep wrote:

" I missed the original, but the idea that OBA's cause metamerism is not
right. If you use carbon inks on OBA paper, you do not suddenly get
metamerism. Bromides containing OBA's did not display metamerism.

Metamerism is due to some ink pigments themselves reacting to UV with a
degree of flourescence, causing a shift in the intensity and/or frequency
of reflected light, and the image colours to change in an unbalanced
manner."

Tony, thanks for your comments on my post and your valuable additions.
However, metamerism is defined as a shift in colors under varying lighting
conditions and significant fluorescence under UV will indeed cause a shift.
It may be a lot more subtle than the metamerism exhibited by carbon pigment
inks, but it's still there. There's simply no way an image on neutral white
looks like the same image with a fluorescing background. Subtle yes. Non
existing, no. Last, I completely agree with your statement about OBs
potential for fading which reveals the underlying yellow of the paper. This
all came up in the context of my consulting to Crane given that Museo papers
have no OBs yet they are also quite "bright."

Rick Colson

--- In DigitalBlackandWhiteThePrint@yahoogroups.com, Tony Sleep
<TonySleep@...> wrote:
>
> If you want to check the effects of OBA's, stick a sheet of 
> perspex/plexiglass over the print. It blocks UV and you'll see the
paper 
> and inks unaffected by flourescence of either OBA's or pigments.


If that's all it takes, it sounds like a plan. No OB fade problems. No
fluorescence. Ink or paper. Paper looks just as yellow as it ever
would, if otherwise archival. Just one problem. You have to like the
look of plastic over the print and hope that it's just as archival:)

Regards
Duane

Hello Andrew,

>Over the years I've seen and tested a few hundred "fine-art" matte  
>and watercolor papers, and I think Hahnemuhle Museum Etching is a  
>good contender as a non-OBA paper. It has as good a Dmax visually as  
>any matte paper I've seen, it feels incredibly nice in the hand (it's  
>350gsm and feels more like 400gsm to me compared with most 300gsm  
>papers) and is great when matted in large sizes because it sits so  
>flat. It also doesn't come across as being too warm in color to me,  
>though the base is definitely not bright white either. It also does  
>not flake or scuff as easily as many other papers in its class with  
>all the pigment inks I've used with it.

Thanks very much, I'll check it out.


Regards,
Clayton


Info on black and white digital printing at    
http://www.cjcom.net/digiprnarts.htm

Hello Richard,

>As an aside, I just read this on a website: 
>"Velvet Fine Art Paper - With a base that is 100% cotton rag,
>buffered >and acid free, this paper is coated with the Enhanced 
>Matte coating..."
>I hadn't realised that EEM and VFA had the same coating.

I have seen this several times and, to be honest, I have my doubts. 
The main thing is yellowing.  We know that EEM yellows very quickly,
in a few weeks (some say days), while VFA takes a long time (I don't
know how long, I've never seen any yellowed VFA; it seems to be very
yellow-resistant).  If they have the same coating then the yellowing
difference would have to be attributed to the paper.  Somehow that
doesn't seem right.  Otherwise they are very similar (contrast and
density; VFA dmax is a bit better).


Regards,
Clayton


Info on black and white digital printing at    
http://www.cjcom.net/digiprnarts.htm

Hi,
if that was a response to my comments about Entrada, I might add that I use a lot of PremierArt Matte BW and almost never have flakes. I can't remember having one in the last few months.

I wonder if the smoother papers are less prone to flaking, such as PremierArt Matte BW and Hot Press? Just a thought.

I'm nearly ready to jump ship and go for another OBA-free rag paper at this point, after a charmed life with Entrada for a while - nearly every print is flaking at present. Very strange and quite unsustainable in terms of wasted materials.

Richard

At 06:44 AM Saturday 1/5/2008, you wrote:
>> Possibly a work area problem...? Just a thought.
>> 
>> Scott
>
>That's my experience. It's especially important to keep unused paper
>in the plastic bag. As well, paper edges abrade, producing dust when
>heavy papers are removed from packages. I think a t-shirt or
>compressed gas can is more effective than brush or squeeze-bulb. 

--
Backroads Essay:
http://picasaweb.google.com/rsmallfield/TheBackroadsOfWarkworth
Greeting Cards available for purchase:
http://picasaweb.google.com/rsmallfield/GreetingCards
http://photos.smallfield.vze.com
http://smallfield.vze.com

   "Nothing determines who we will become so much a those 
   things we choose to ignore."
   --Sandor Minab

Tony Sleep wrote:

> I missed the original, but the idea that OBA's cause metamerism is not 
> right. If you use carbon inks on OBA paper, you do not suddenly get 
> metamerism. Bromides containing OBA's did not display metamerism.
> 
> Metamerism is due to some ink pigments themselves reacting to UV with a 
> degree of flourescence, causing a shift in the intensity and/or frequency 
> of reflected light, and the image colours to change in an unbalanced 
> manner. Such fluorescence can make it hard or impossible to adequately 
> profile inks that have this behaviour, as the colour of the illuminant and 
> amount of UV changes the image colour balance.
> 
> If you use metameric inks on papers containing OBA's you are going to make 
> matters a little worse, but the real problem is the inks susceptibility to 
> flourescence, not the OBA. They'll substantially do it anyway, even on 
> papers without OBA's.
> 
> That is *the* issue with printing B&W using CMY pigments, and why 
> metamerism is a problem with such inks to a greater or lesser degree. I 
> have fairly recently gone from Generations G4 pigments to HP Vivera 
> pigments, and the newer HP inks are vastly less metameric, OBA in the 
> paper or not.

Metamerism (as we define it here) is caused by changing 
light spectra in general. UV light and UV light + 
fluorescence is just a part of changed light conditions. It 
can happen between two light sources both without UV light.

You have gone from a CMYK or a CcMmYK(k)  inkset to an 
inkset that has 3 grey inks replacing composite grey mixes 
with neutral grey inks, with the Z3100 that's extended to 4 
grey inks and extra hues to substitute CM and MY  mixes etc. 
That's the main cause for less metamerism with Vivera inks. 
4 and 6 inksets never delivered consistent neutral B&W 
prints, metamerism (including metamerism as a result of UV 
light and UV light and fluorescence).  "The" issue isn't 
UV>fluorescence>metamerism but how one can reduce color 
mixing in the first place by substituting color mixes by a 
single pigment. That single pigment should then show a low 
metamerism on itself, carbon does that, the neutral grey 
inks of HP Vivera (carbon + a neutraliser colorant ) does 
that too.
The Lyson Small Gamut dye ink didn't even while its CMY 
saturation was brought to a minimum.

I have used Generations G4 and am using the Vivera Z3100 inkset.

> 
> If you want to check the effects of OBA's, stick a sheet of 
> perspex/plexiglass over the print. It blocks UV and you'll see the paper 
> and inks unaffected by flourescence of either OBA's or pigments.

PMMA doesn't block UV. It actually lets more UV through than 
plain glass. For both there are filtered and less filtered 
versions. A plain sheet of Perspex shows more fluorescence 
in the print with UV light on it than glass will do. You 
better try outdoor qualities of PolyCarbonate then as they 
have UV filters applied in co-extrusion to protect the 
material itself against UV light. That makes the material 
more grey or slightly yellow however. It scratches more 
easily than Perspex too. PMMA is very UV light resistant and 
one of the best transmitters of light in total.

http://en.wikipedia.org/wiki/Acrylic_glass

If you would use a UV filter frame glass (like plain window 
glass is in a way) you would also loose the OBA effect to a 
degree. In that case less OBA in the paper, coating, is a 
wiser step for framed and unframed prints. Not to mention 
the more complex profile creation for framed or unframed 
prints on OBA containing or non-OBA papers with a 
Spectrometer that has a UV filter on the sensor or on the 
light source or no filter at all. My choice is (if my 
customers allow it) to use media with less OBA  and profile 
with a Spectrometer sans UV filter. But I can do both.



-- 
Met vriendelijke groeten, Ernst


|  Dinkla Grafische Techniek  |
|     www.pigment-print.com    |
|             ( unvollendet )            |

On 05/01/2008 Ernst Dinkla wrote:
> Metamerism (as we define it here) is caused by changing
> light spectra in general. UV light and UV light +
> fluorescence is just a part of changed light conditions. It
> can happen between two light sources both without UV light.

Yes, OK. You forced me to go away and read up more on pigment ink 
metamerism. I had not appreciated that the greater metamerism of pigments 
was due to the absence of proper mixing that occurs with dyes and dye-sub.

More annoyingly, that it is a human perceptual issue as well. 
http://www.cs.umb.edu/%7Eram/courses/color/albers.htm is fascinating.

> The Lyson Small Gamut dye ink didn't even while its CMY
> saturation was brought to a minimum.

Certainly was highly metameric in the samples I saw. You had to go a long 
way from any sort of neutral tone to try and hide the effects.

> I have used Generations G4 and am using the Vivera Z3100 inkset.

Lucky man :)

> PMMA doesn't block UV. It actually lets more UV through than
> plain glass. 

Again, you're right. I thought it was all grades of acrylic that filtered 
UV. It turns out to be just some special grades like OP-3, which is 
designed for museum/art use.

-- 
Regards

Tony Sleep
http://tonysleep.co.uk