Digital BW, The Print

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
> >> http://www.PaulRoark.com
> > 
> > 
> > 
> > Please visit the Group Homepage to check the Files, Bookmarks, 
Polls and other
> > resources as they are often being updated. The page is at:
> > 
> > http://groups.yahoo.com/group/DigitalBlackandWhiteThePrint
> > 
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> > 
> 
> ----------------------
> Robert Morrison
> rmorrison@p...
> 
> 310-397-2704
> 
> 4131 Bledsoe Ave.
> Los Angeles, CA 90066