Digital BW, The Print

Am I missing something here?  Are the last two posts saying that testing the fading of one ink (brand) on
several different papers is invalid?  Why?

And are you saying that Wilhelm has proved itself to be reliable?....There are a lot of people out there who
would argue with that.

And finally, the below tests were done in a controlled 'fader', all papers entering together, and not in some
window where the weather changes or the angle of the sun, relative to time of year changes....I would think at
the very least, that these tests would be considered empirical.

Harvey Ferdschneider
partner, SKID Photography, NYC

broyaliii@... wrote:

> The competence of the home enthusiast via-a-vis the facilities
> dedicated to testing and reporting image permanence of digital
> and traditional photographic print materials (i.e., Wilhelm, RIT)
> has relegated the reports from home to the anecdotal.
>
> Unfortunately, this latest broadcast, which compares two inks
> printed on different media, not only brings to question the
> competence, but also the motivation and integrity of the tester.
>
> JB
>
>
>
> --- In DigitalBlackandWhiteThePrint@y..., Robert Morrison
> <rmorrison@p...> wrote:
> > Ditto, seems rather strange.  Why didn't you just print Piezo on EAM?
> >
> > Also...with regards to Steadman's note....it is absolutely critical that
> > prints are made at the same time because of natural warming that occurs...at
> > least with Piezo (don't know about the MIS inks).  Starting a fade at Print
> > Time = 0 and Print Time = 2 weeks will certainly yield different results.
> >
> > Robert
> >
> > On 10/17/01 7:21 AM, "Cathy Van Berg" <vanbergc@y...> wrote:
> >
> > > Let me make sure I'm understanding this correctly...
> > >
> > > You printed Piezo and MIS VM/VM X3 on different papers for this test?
> > > If that is true, then you cannot draw valid conclusions by comparing
> > > what I see as apples and oranges... You may say that for a given
> > > paper, these inks fade x amount, but you cannot compare them to each
> > > other. If it was not your intent to compare fading and warming between
> > > the inks, then that was not clear to me...
> > >
> > > Thanks,
> > > Cathy
> > >
> > >
> > >
> > > --- In DigitalBlackandWhiteThePrint@y..., "Paul Roark"
> > > <paul.roark@v...> wrote:
> > >> In the latest fade test series, I put test strips of Piezo on Hahnemuhle
> > >> German Etching, MIS VM (nc curve) on EAM, and an experimental
> > > variable-tone
> > >> called VM X3 that prints with the same curves as MIS VM (nc curve).
> > >>
> > >> I measured fading as a percentage of the starting value and warming
> > > as the
> > >> change in the difference between the RGB red and blue channel
> > > measures.  The
> > >> test strips were scanned into Photoshop with an Epson 1600, and the
> > >> Histogram tool was used to make the measurements.
> > >>
> > >> 0% (paper white) warming:  EAM (2 samples) 2.4 & 2.3 units; German
> > > Etching
> > >> 0.6 units.
> > >>
> > >> 50% patch measures:
> > >>
> > >> Piezo on German Etching -- Warming = 10.3 units,   Fading = 9.2%
> > >>
> > >> MIS VM on EAM           -- Warming = 9 units,      Fading = 6.9%
> > >>
> > >> VM X3 on EAM            -- Warming = 3.1 units,    Fading = 5%
> > >>
> > >> Note that most of the warming had taken place by the 100 hour
> mark.  The
> > >> fading was also fastest at first, but it continues much more so
> than the
> > >> warming.
> > >>
> > >> The fading of the 90% patch needs to be mentioned.  I measure the
> > > 90% patch
> > >> as opposed to the pure 100% patch to see what the shadows will
> be doing
> > >> because it may indicate whether there is a negative interaction
> > > between the
> > >> black ink and something in the midtone inks (and, of course, the
> > > paper is a
> > >> huge factor that affects all the patches).  A number of people
> have
> > > noted
> > >> that some components, perhaps including dyes, can actually act as
> > > catalysts
> > >> in fading other components, for example, the black ink.
> > >>
> > >> (Note that in my fader the light is intense, so the black
> patches are
> > >> undoubtedly warmer than the lighter patches.  This is probably
> also
> > > the case
> > >> in the "south window tests" and perhaps all accelerated fade
> tests.  One
> > >> would expect, therefore, to see more fading in the darker
> patches.)
> > >>
> > >> To measure the fading of the 90% patch, I converted the mode to
> > > grayscale
> > >> and used levels to set the white and black points of the control
> > > strips as
> > >> accurately as possible.  The percentage of fading is a
> percentage of
> > > the 90%
> > >> control strip for each set.  (The MIS VM and X3 are about the
> same.)
> > >>
> > >> 90% patch fading:
> > >>
> > >> Piezo on German Etching -- 55%
> > >>
> > >> VM X3 on EAM -- 18%.
> > >>
> > >> Also of note, the Piezo 7000 black on the German Etching paper is
> > > slightly
> > >> darker than the MIS VM black on EAM printed with either the 3000
> or
> > > 1160.
> > >> When the levels sets the Piezo/German Etching black on 100%, the
> MIS VM
> > >> blacks read 98%.
> > >>
> > >> I have sent a Jpeg of the scans to Martin for inclusion in the
> Message
> > >> Related Files section of the forum.  I did notice, however, that
> the
> > > Jpeg
> > >> compression slightly affected the measures.  So, measuring those
> > > Jpegs may
> > >> result in slightly different readings than above.
> > >>
> > >> Paul




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