QTR-Quadtone RIP

(Sorry if this is too OT, but the issue was raised here.)

Jon or others,

... Piezography pure Carbon full ink sets are leading the OEMs in longevity
> for b&w at Aardenburg ...
>
I obviously agree with Jon here.  The 100% carbon inksets can easily beat
the OEM inksets with respect to longevity.

I briefly looked at the Aardenburg fade tests of Piezo Carbon Sepia.  I
noticed 2 were with Hahnemuhle papers (Photo Rag 188 and W. Turner).  One of
those was sprayed and one not.  Yet the results look about equally
excellent.  (Papers, of course, can make a significant difference in
results, but ...)

This brings up an issue about which I've never really seen convincing
evidence.

Regarding longevity of 100% carbon inksets only, does using these sprays
provide any significant   boost to their light-fastness?

We do have evidence that for the dyes they can make a significant
difference, and I'm quite sure tests support that UC pigments benefit from
the spaying.  Other tests I'm aware of appear to show a benefit from sprays
for the blended B&W inksets.  But I'm focusing just on 100% carbon here.  I
don't recall any tests that show one way or the other.

I do think sprays add to abrasion resistance marginally, but they also lower
dmax.

I, personally, would be very happy if 100% carbon inksets were lightfast
enough that those who use them can feel comfortable in NOT using the
(usually toxic) sprays.

Paul
www.PaulRoark.com 


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

Paul,

As you note, the Piezography Sepia inks do not need anything to make them more stable. It is pure carbon and has great longevity on its own.

But, I think Mark probably is testing examples on both pigment and dye with UV sprays, and if he reads this list can answer with some authority on the subject.

Best,

Jon





--- In QuadtoneRIP@yahoogroups.com, Paul Roark <roark.paul@...> wrote:

>
> (Sorry if this is too OT, but the issue was raised here.)
> 
> Jon or others,
> 
> ... Piezography pure Carbon full ink sets are leading the OEMs in longevity
> > for b&w at Aardenburg ...
> >
> I obviously agree with Jon here.  The 100% carbon inksets can easily beat
> the OEM inksets with respect to longevity.
> 
> I briefly looked at the Aardenburg fade tests of Piezo Carbon Sepia.  I
> noticed 2 were with Hahnemuhle papers (Photo Rag 188 and W. Turner).  One of
> those was sprayed and one not.  Yet the results look about equally
> excellent.  (Papers, of course, can make a significant difference in
> results, but ...)
> 
> This brings up an issue about which I've never really seen convincing
> evidence.
> 
> Regarding longevity of 100% carbon inksets only, does using these sprays
> provide any significant   boost to their light-fastness?
> 
> We do have evidence that for the dyes they can make a significant
> difference, and I'm quite sure tests support that UC pigments benefit from
> the spaying.  Other tests I'm aware of appear to show a benefit from sprays
> for the blended B&W inksets.  But I'm focusing just on 100% carbon here.  I
> don't recall any tests that show one way or the other.
> 
> I do think sprays add to abrasion resistance marginally, but they also lower
> dmax.
> 
> I, personally, would be very happy if 100% carbon inksets were lightfast
> enough that those who use them can feel comfortable in NOT using the
> (usually toxic) sprays.
> 
> Paul
> www.PaulRoark.com 
> 
> 
> [Non-text portions of this message have been removed]
>

On 03/19/2011 06:11 AM, piezobw wrote:
> Paul,

> But, I think Mark probably is testing examples on both pigment and dye with UV sprays, and if he reads this list can answer with some authority on the subject.
>
> Best,
>
> Jon

Mark still considers the gas blocking of varnishes (and possibly gloss 
enhancers) as the likely reason for extended longevity and not a UV 
filter in the varnish. Too thin a layer for real UV blocking. On canvas 
layers like that are usually thickers so the UV filter could work there.

Whether the gas block does anything with carbon, semi-carbon or other 
B&W inks is another question. Papers that contain FBA should in theory 
benefit too as the FBAs are in essence dyes more gas fading prone next 
to their UV degradation. One should look into the detail of Aardenburg 
reports which patches exactly are shifting and the direction of the 
shift. Usually paper white gives more white reflectance after the first 
hours of exposure before shifting to the wrong direction (if ever). Not 
a bad shift as it is limited. As I understand from another remark by 
Mark the paper/coating dries in the frame and causes that first effect 
of more reflectance. That effect is however considered a fading shift in 
the end results.


-- 
Met vriendelijke groeten,   Ernst

Try: http://tech.groups.yahoo.com/group/Wide_Inkjet_Printers/

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