Digital BW, The Print

Paul: <SNIP ... While we're on the subject, note the extent to which 
"reciprocity failure" of the accelerated tests gets more serious as the 
illumination level
increases.  ... In short, if one tries to project "years of display" without 
considering reciprocity failure, the exaggeration of the predicted life could 
be huge.>

Yes, indeed. Reciprocity failure is the Achilles Heel of accelerated testing, 
IMO, significantly *underestimating* fading. And what's interesting is that 
Henry Wilhelm has known this all along, at least since the mid-'70s. In fact, 
he devotes a whole table to it in his 1993 book. Yet, the latest published 
testing results from Wilhelm all assume a reciprocity failure of ZERO. Not 
quite sure why. Supposedly, his new test methodology takes this into account 
somehow. We'll see.

Harald Johnson
author, "Mastering Digital Printing"
DP&I.com ( http://www.dpandi.com )

I think reciprocity failure  is the key to why Cone has consistently refused
to put "years" on longevity data.  It is a really foolish thing to
do...particularly when we want these things to last for a 100 years...there
is absolutely no way to give a valid 100 year projection...until we have
prints that have been around that long.  In the end the best we can hope for
is what Cone has given us relative testing, with full published results done
by a reputable testing group (RIT)...and hopefully more comparative testing
done by RIT in the future.  I've said this many times before...and I'll say
it again...it would also be nice to see some archivally printed silver
prints included in this testing as well...now whose processing and what
darkroom conditions is a big topic for debate...but any data along those
lines would be a help at this point.

Robert

On 11/9/02 9:09 AM, "hjswim2@..." <hjswim2@...> wrote:

> Paul: <SNIP ... While we're on the subject, note the extent to which
> "reciprocity failure" of the accelerated tests gets more serious as the
> illumination level
> increases.  ... In short, if one tries to project "years of display" without
> considering reciprocity failure, the exaggeration of the predicted life could
> be huge.>
> 
> Yes, indeed. Reciprocity failure is the Achilles Heel of accelerated testing,
> IMO, significantly *underestimating* fading. And what's interesting is that
> Henry Wilhelm has known this all along, at least since the mid-'70s. In fact,
> he devotes a whole table to it in his 1993 book. Yet, the latest published
> testing results from Wilhelm all assume a reciprocity failure of ZERO. Not
> quite sure why. Supposedly, his new test methodology takes this into account
> somehow. We'll see.
> 
> Harald Johnson
> author, "Mastering Digital Printing"
> DP&I.com ( http://www.dpandi.com )

>>I've said this many times before...and I'll say
it again...it would also be nice to see some archivally printed silver
prints included in this testing as well...now whose processing and what
darkroom conditions is a big topic for debate...but any data along those
lines would be a help at this point.

Robert

Indeed it would be interesting to subject an inkjet and silver print to the same test, since a silver print is pretty much the archival standard, along with pt/pd.  I have a number of silver prints with some age on them (30-40 years)that look fine.  They were processed conventionally, nothing special (fiber paper, two-tray fixing, wash, hypo clear, selenium in various dilutions, effective wash in print washer, air dry on fiberglass screens, dry mount on pure rag museum board).  Our local museum has an early Moonrise that is displayed under wretched conditions, and to my surprise it looks to be excellent.  I've always assumed that a properly processed silver or pt/pd print, displayed under reasonable conditions (not in near darkness as museums are prone to do now) in a sealed frame, was pretty much bullet proof.  But I have no idea what would happen if it was subject to very high levels of UV or whatever, nor do I remember reading about any test like that.  I don't have it handy, but as I recall AA's "The Print" has some data on estimated print lives and archival-ness in general.

The big difference would be between fiber and RC silver prints.  I've never understood why anyone would use RC.  It is a royal PITA in the darkroom because you have to stop what you're doing and get it out of the wash, since excessive washing will cause problems.  You can leave fiber prints in a holding tray with a siphon all day long if you want.  Plus its laminate construction is bound to cause problems.  Plus it looks bad.  So I think the better comparison would be inkjet to a properly processed fiber silver print.

  --Ken

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

----- Original Message -----

From: "Ken Carney" <kcarney1@...>
To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
Sent: Sunday, November 10, 2002 2:09 AM
Subject: Re: [Digital BW] Re: PiezoTone Fade Data


> ...
> The big difference would be between fiber and RC silver prints.  I've
never understood why anyone would use RC.
> It is a royal PITA in the darkroom because you have to stop what you're
doing and get it out of the wash, since
> excessive washing will cause problems.  You can leave fiber prints in a
holding tray with a siphon all day long if
> you want ...

I wash my RC prints around 30 minutes and never had any problem... These
papers can handle rough treatment and are excellent for proof prints.

Regards,
Loris.

I stand corrected.  The RC papers are good for contact sheets and proofs
that you want to hang up for a while until you decide how to print it.  But,
with the fiber papers it is nice to hold them all day in a big tray with a
siphon, then finish them all at once.  All of that is coming to an end,
however...I put the MIS VM-S inks in my printer yesterday.  So far, so good.
I haven't been able to get the MIS inks to work for me in the past, but now
they do for some reason.  Personally, I wish they'd hurry up and get all
this digital stuff perfected so I don't have to go back in the darkroom.
It's cold and it's dark and you can't sip a Scotch (at least you're not
supposed to) waiting for inspiration to strike.

  --Ken

----- Original Message -----
From: "Loris Medici" <loris.medici@...>
To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
Sent: Monday, November 11, 2002 12:10 AM
Subject: Re: [Digital BW] Re: PiezoTone Fade Data


>
> ----- Original Message -----
> From: "Ken Carney" <kcarney1@...>
> To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
> Sent: Sunday, November 10, 2002 2:09 AM
> Subject: Re: [Digital BW] Re: PiezoTone Fade Data
>
>
> > ...
> > The big difference would be between fiber and RC silver prints.  I've
> never understood why anyone would use RC.
> > It is a royal PITA in the darkroom because you have to stop what you're
> doing and get it out of the wash, since
> > excessive washing will cause problems.  You can leave fiber prints in a
> holding tray with a siphon all day long if
> > you want ...
>
> I wash my RC prints around 30 minutes and never had any problem... These
> papers can handle rough treatment and are excellent for proof prints.
>
> Regards,
> Loris.
>
>
>
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