Digital BW, The Print

Screw Wilhelm Imaging Research.
What credibility does Wilhelm have with his no show on the Web for the last
2 years ?
54 years for Semigloss? why so inexact? can't he give us the days and hours
while he's at it?
Vilhelm, ve need someone else to lead the vay.

> From: Marc McCarron <mamccarron@...>
> Reply-To: DigitalBlackandWhiteThePrint@yahoogroups.com
> Date: Tue, 29 Oct 2002 01:28:56 -0500
> To: DigitalBlackandWhiteThePrint@yahoogroups.com
> Subject: [Digital BW] Wilhelm Imaging Research
> 
> Screw Wilhelm Imaging Research.
> What credibility does Wilhelm have with his no show on the Web for the last
> 2 years ?
> 54 years for Semigloss? why so inexact? can't he give us the days and hours
> while he's at it?
> Vilhelm, ve need someone else to lead the vay.

Here is another way to look at this issue. I usually just say 'thank you'
when someone gives me something for free (whether it is information or a
nice piece of pie) and if I don't like it, I just quietly through it away.

Wendel

It ain't exactly free. Whilhelm sells his services to manufacturers 
and resellers who have to factors in these costs in the selling price 
of their products.
Since these charges are hidden we tend to thinks that its free.
Cheers,
Andre

--- In DigitalBlackandWhiteThePrint@y..., Wendel White <wendel@b...> 
wrote:
> > From: Marc McCarron <mamccarron@c...>
> > Reply-To: DigitalBlackandWhiteThePrint@y...
> > Date: Tue, 29 Oct 2002 01:28:56 -0500
> > To: DigitalBlackandWhiteThePrint@y...
> > Subject: [Digital BW] Wilhelm Imaging Research
> > 
> > Screw Wilhelm Imaging Research.
> > What credibility does Wilhelm have with his no show on the Web 
for the last
> > 2 years ?
> > 54 years for Semigloss? why so inexact? can't he give us the days 
and hours
> > while he's at it?
> > Vilhelm, ve need someone else to lead the vay.
> 
> Here is another way to look at this issue. I usually just 
say 'thank you'
> when someone gives me something for free (whether it is information 
or a
> nice piece of pie) and if I don't like it, I just quietly through 
it away.
> 
> Wendel

Wendel White's promotion of civility on the list is very welcome to me.

Wendel's e-mail address intrigued me, so I visited his web site

http://blacktowns.org/

and found a nicely-done site about his interesting project 
documenting small-town African-American life in Southern New Jersey 
with B&W photos. Made me wish I could see the associated Noyes museum 
exhibit in New Brunswick (without traveling 3000 miles to do it).

As for Marc's take on Wilhelm, despite Wilhelm still being "AWOL" as 
far as we (if not his clients?), are concerned, Wilhelm still has a 
lot of credibility with me. I do wish his (and RIT's) clients would 
publish more of the results of their testing. Maybe even _before_ 
they start to sell the products tested!

Marc is right about Wilhelm's 54-year and other preliminary "point" 
estimates: they are misleadingly precise. And I wish Wilhelm would 
report them as the midpoints of ranges which are two standard 
deviations wide. But if for some reason he can't, I'd rather have 54 
than, say, 50, along with the inaccuracy associated with rounding 
error. Of course, the 54 itself is presumably the rounded-off average 
of an appropriately-large number of samples - but I wish we knew how 
many.

Wilhelm's clients might, however, think - largely with good reason I 
suspect - that, unlike me, most consumers of Wilhelm's data have 
little appetite for statistics, know that estimates are estimates, 
and make allowances for that. And since Wilhelm's clients - not we - 
are paying for the work, who am I to complain? Well, I am _their_ 
client. So I feel entitled to complain - but about what those clients 
do (mostly don't do) rather than about what Wilhelm does for them, 
which I expect is done to a relatively high standard. I think we 
should focus our criticism on his clients' marketing.

Sam McCandless             samcc@...

> > From: Marc McCarron <mamccarron@...>
> > Reply-To: DigitalBlackandWhiteThePrint@yahoogroups.com
> > Date: Tue, 29 Oct 2002 01:28:56 -0500
> > To: DigitalBlackandWhiteThePrint@yahoogroups.com
> > Subject: [Digital BW] Wilhelm Imaging Research
> >
> > Screw Wilhelm Imaging Research.
> > What credibility does Wilhelm have with his no show on the Web for the last
> > 2 years ?
> > 54 years for Semigloss? why so inexact? can't he give us the days and hours
> > while he's at it?
> > Vilhelm, ve need someone else to lead the vay.
>
>Here is another way to look at this issue. I usually just say 'thank you'
>when someone gives me something for free (whether it is information or a
>nice piece of pie) and if I don't like it, I just quietly through it away.
>
>Wendel

Can someone help me interpret these numbers?  Or point to a resource to  
help me understand what is being said.  I would like to understand:

1) What is being measured when and estimate of 54 years is made.  Is  
that density, or color shift, or some proprietary combination of  
measured attributes.

2) In light of the answer to question one above, at what point in  
measuring that attribute did the print no longer last.  I mean if the  
average of the samples was 50 years, what was the attribute change at  
50 years?  10% change, a 'noticeable' change? or something else.

3) Does the tester assume a linear continuance of the change in that  
measured attribute. Is that reasonable to assume.  For example if the  
measurement changes 5% in 3 months can you extrapolate that using a  
linear equation to 50 years?

4) How intense is 50 lux.  Would that be a 'normal' viewing  
environment. Is there a linear relationship between fading and light  
intensity.  For example, is 50 lux for 300 days the same as 500 lux for  
30 days?

5) Do all of Wilhelms' test results use the same test criteria and test  
setup?  Are test results for company A using the same framing (glass),  
light source, humidty etc as the testing for company B.

There is, obviously, a lot I don't know about this testing and the  
results.

Thanx

Kevin Gulstene

On Tuesday, October 29, 2002, at 06:48 AM, Sam A. McCandless wrote:

> Wendel White's promotion of civility on the list is very welcome to me.
>
> Wendel's e-mail address intrigued me, so I visited his web site
>
> http://blacktowns.org/
>
> and found a nicely-done site about his interesting project
> documenting small-town African-American life in Southern New Jersey
> with B&W photos. Made me wish I could see the associated Noyes museum
> exhibit in New Brunswick (without traveling 3000 miles to do it).
>
> As for Marc's take on Wilhelm, despite Wilhelm still being "AWOL" as
> far as we (if not his clients?), are concerned, Wilhelm still has a
> lot of credibility with me. I do wish his (and RIT's) clients would
> publish more of the results of their testing. Maybe even _before_
> they start to sell the products tested!
>
> Marc is right about Wilhelm's 54-year and other preliminary "point"
> estimates: they are misleadingly precise. And I wish Wilhelm would
> report them as the midpoints of ranges which are two standard
> deviations wide. But if for some reason he can't, I'd rather have 54
> than, say, 50, along with the inaccuracy associated with rounding
> error. Of course, the 54 itself is presumably the rounded-off average
> of an appropriately-large number of samples - but I wish we knew how
> many.
>
> Wilhelm's clients might, however, think - largely with good reason I
> suspect - that, unlike me, most consumers of Wilhelm's data have
> little appetite for statistics, know that estimates are estimates,
> and make allowances for that. And since Wilhelm's clients - not we -
> are paying for the work, who am I to complain? Well, I am _their_
> client. So I feel entitled to complain - but about what those clients
> do (mostly don't do) rather than about what Wilhelm does for them,
> which I expect is done to a relatively high standard. I think we
> should focus our criticism on his clients' marketing.
>
> Sam McCandless             samcc@...
>
>
>>> From: Marc McCarron <mamccarron@...>
>>> Reply-To: DigitalBlackandWhiteThePrint@yahoogroups.com
>>> Date: Tue, 29 Oct 2002 01:28:56 -0500
>>> To: DigitalBlackandWhiteThePrint@yahoogroups.com
>>> Subject: [Digital BW] Wilhelm Imaging Research
>>>
>>> Screw Wilhelm Imaging Research.
>>> What credibility does Wilhelm have with his no show on the Web for  
>>> the last
>>> 2 years ?
>>> 54 years for Semigloss? why so inexact? can't he give us the days  
>>> and hours
>>> while he's at it?
>>> Vilhelm, ve need someone else to lead the vay.
>>
>> Here is another way to look at this issue. I usually just say 'thank  
>> you'
>> when someone gives me something for free (whether it is information  
>> or a
>> nice piece of pie) and if I don't like it, I just quietly through it  
>> away.
>>
>> Wendel
>
>
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> From: "Sam A. McCandless" <samcc@...>
> Reply-To: DigitalBlackandWhiteThePrint@yahoogroups.com
> Date: Tue, 29 Oct 2002 06:48:53 -0800
> To: DigitalBlackandWhiteThePrint@yahoogroups.com
> Cc: Wendel White <wendel@...>
> Subject: Re: [Digital BW] Wilhelm Imaging Research
> 
> Wendel White's promotion of civility on the list is very welcome to me.
> 
> Wendel's e-mail address intrigued me, so I visited his web site
> 
> http://blacktowns.org/
> 
> and found a nicely-done site about his interesting project
> documenting small-town African-American life in Southern New Jersey
> with B&W photos. Made me wish I could see the associated Noyes museum
> exhibit in New Brunswick (without traveling 3000 miles to do it).

Thanks for the compliment and the plug!

Wendel

Based on repeated visits to their website over the years, my 
understanding is that they are now in the construction business ;-)


Michael A. Schwarz
Corporate, Editorial and Documentary Photojournalism
www.michaelschwarz.com
ms@...

Kevin: <Can someone help me interpret these numbers? Or point to a resource 
to help me understand what is being said.  I would like to understand: ...>

The following is based on my conversation with Henry Wilhelm earlier this 
year and my subsequent research for my new book, in which I have an entire 
chapter on print permanence. Corrections are welcome.


<1) What is being measured when and estimate of 54 years is made. Is that 
density, or color shift, or some proprietary combination of measured 
attributes.>

Wilhelm Imaging Research's (WIR) most well-known tests are accelerated 
lightfastness or "light stability" tests. Their display-life predictions are 
a combination of lightfastness and dark stability data.

WIR uses an instrument-measured test that ends when specified density 
endpoint values are reached. 


<2) In light of the answer to question one above, at what point in  measuring 
that attribute did the print no longer last. I mean if the average of the 
samples was 50 years, what was the attribute change at 50 years? 10% change, 
a 'noticeable' change? or something else.>

The endpoint is a percentage change in density. Wilhelm has developed his own 
visually-weighted criteria set for these values. The predictive print life is 
then extrapolated out in years based on WIR's reference display conditions 
(450 lux for 12 hours per day).


<3) Does the tester assume a linear continuance of the change in that   
measured attribute. Is that reasonable to assume.  For example if the  
measurement changes 5% in 3 months can you extrapolate that using a linear 
equation to 50 years?>

This is one of the main problems with accelerated tests. This refers to the 
Law of Reciprocity, and unfortunately, the law fails. (The law says that the 
total amount of fading is equal to the total amount of energy exposure: time 
X intensity. Doubling the time but halving the intensity would, in theory, 
yield the same result.) WIR has historically assumed reciprocity failure to 
be zero. They are supposedly changing this assumption, but I don't know if 
the current tests reflect that or not.


<4) How intense is 50 lux.  Would that be a 'normal' viewing environment. Is 
there a linear relationship between fading and light intensity. For example, 
is 50 lux for 300 days the same as 500 lux for 30 days?>

Where did you get 50 lux from? That's an extremely low light level; even 
lower than most museum lighting for prints. Wilhelm's reference is 450 lux. 
Barbara Vogt says that 215 lux is about average in a U.S. home (which I also 
measured in my foyer yesterday). A wall exposed to sunlight can register up 
to 50,000 lux!


<5) Do all of Wilhelms' test results use the same test criteria and test  
setup?  Are test results for company A using the same framing (glass), light 
source, humidity etc as the testing for company B.>

The latest info I have has WIR doing consistent 35 Klux tests with 
glass-filtered cool white fluorescent illumination at 24º C and 60% RH.


<There is, obviously, a lot I don't know about this testing and the results.>

So read my book! ;-) (a message about it follows)

Hope that helps a little.

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