Digital BW, The Print

Robert,

You wrote:

>Forgive me if you have already answered this before...but what are the
>wavelength characteristics of the light source in your fader?  I'm a little
>confused as to why the Xenon lightsource fades that RIT are doing of these
>same inks are not showing this same pattern of results.

I use fluorescent light.  I'm aware that it has some spikes in the spectrum,
but I have not seen anything very convincing that these make a significant
difference.  Also, the light level I use is much less intense than some of
the Xenon light sources that are used to accelerate fading.  As such, I
think my procedure may suffer from less of the reciprocity effects.

At any rate, none of these fade tests is perfect, but I'm convinced they are
better than nothing.  I note that Wilhelm still appears to use a fluorescent
light source.

Have you seen any RIT results with the PiezoTone inksets?  I'd like to see
what they look like.  When I compare the graphs of the fading I get with my
fluorescent light source, they look similar to the RIT graphs of the MIS
Archival color inks that MIS has published on its website.

Paul
http://www.PaulRoark.com

_________________________________________


On 9/1/02 12:12 PM, "Paul Roark" <paul.roark@...> wrote:

> Three PiezoTone test strips reached 300 hours (actually 304 hours) in my
> fader Saturday.  They were PiezoTone Selenium (PT-S) on PhotoRag (PR),
PT-S
> on Epson Archival Matte (EAM), and, for comparison purposes,
PiezoTone-Warm
> Neutral (PT-WN) on EAM.
>
> In general, there were no surprises.  The PT-S midtones performed
extremely
> well, with very minimal fade and virtually no midtone warming.
>
> The black ink, however, showed substantial fade and warming, which, with
the
> cooler PT-S midtones, causes a significant neutral-to-warm cross-over
> between 85% and 95%.  Whether this is a problem in your particular prints
is
> a subjective issue.  However, the resulting prints are not truly
"selenium"
> tone after the shadow tones have warmed up.  At least with my
selenium-toned
> silver prints the shadows get increasingly cool, not warm, as the density
> increases.
>
> A scan of the test strips can be seen in the Files section of this forum.
> The files section is at:
> http://groups.yahoo.com/group/DigitalBlackandWhiteThePrint/files/
>
> Then following the links:  Files > Ink Sets > PiezoTones.  The file name
is
> "PT-Sel-PR & EAM PT-NW-EAM 304 Hr Fade.jpg."
>
> Also, as expected, the black ink showed less fading and warming on EAM
than
> on PhotoRag.  The 100% patch dropped from a density of 1.82 to 1.64 on PR;
it
> dropped from 1.71 to 1.62 on EAM.  The PR 100% patch warmed 0.11 units,
> while the EAM 100% patch warmed 0.06 units.  (Warming is measured as the
> change in the difference between the cyan and yellow readings.)
>
> Note that these test strips were printed by Martin using a 1280 and CIS.
As
> such, they appear to have been totally unaffected by the problems Jon Cone
> described in his August 29 "PiezoTone News" posting on the Piezo 3000
forum.
> See
> http://groups.yahoo.com/group/piezography3000/message/19609
>
> Also cross-posted by Julian at
> http://groups.yahoo.com/group/DigitalBlackandWhiteThePrint/message/18795
>
> The problem Jon described appears to be ink separation caused by the
sponge
> material used in certain 1280 pre-loaded carts.  They are changing carts,
> but appear also to be changing the dispersion characteristics of the PT-S
> inks.  As such, the final PT-S formula may be slightly different than this
> one.
>
> The X-Rite densitometer readings are below.
>
> PT-S PR 50%    Control: c=0.69, m=0.71, y=0.72, visual=0.70;
> 304 Hr: c=0.68, m=0.70, y=0.71, visual=0.69;
>
> 100%    Control: c=1.82, m=1.81, y=1.80, visual=1.82;
> 304 Hr: c=1.61, m=1.68, y=1.70, visual=1.64;
>
> 85% to 95% tone change (change in [c-y]):
> Control: 85% 0.01 unit cool to 95% 0.03 cool;
> 304 Hr:  85% c=y (neutral) to 95% 0.08 warm.
>
>
> PT-S EAM 50% Control: c=0.68, m=0.69, y=0.68, visual=0.69;
>  304 Hr: c=0.68, m=0.69, y=0.69, visual=0.69;
>
>  100% Control: c=1.71, m=1.72, y=1.72, visual=1.71;
>  304 Hr: c=1.60, m=1.65, y=1.67, visual=1.62;
>
> 85% to 95% tone change (change in [c-y]):
> Control: 85% 0.01 cool to 95% c=y (neutral);
> 304 Hr: 85% 0.01 warm to 95% 0.07 warm.
>
> PT-WN EAM 50% Control: c=0.64, m=0.65, y=0.67, visual=0.65;
>   304 Hr: c=0.66, m=0.67, y=0.70, visual=0.67;
>
>   100% Control: c=1.70, m=1.72, y=1.74, visual=1.71;
>   304 Hr: c=1.64, m=1.68, y=1.70, visual=1.66;
>
> 85% to 95% tone change (change in [c-y]):
> Control: 85% 0.02 warm to 95% 0.02 warm
> 304 Hr: 85% 0.03 warm to 95% 0.06 warm.
>
>
> Paul
> http://www.PaulRoark.com