Digital BW, The Print

The great thing about Livick's and Bill Waterson's (who actually 
conducted the test in California) testing is they had the prints set 
up on boards that could constantly be moved to always be pointing 
directly at the sun.

Bill would take a reading every hour on the hour and then adjust the 
prints so they would continue to be directly facing the sun.

Using the sunlight in this method is, in my opinion, the "torture 
test" for ink fading.

Is there a more, for all practicle purposes, a worse scenario than 
direct sunshine?

Scott

--- In DigitalBlackandWhiteThePrint@yahoogroups.com, John Malcolm 
<johnmalcolm@f...> wrote:
>
> I am impressed with the breadth of interest here in light values, 
> cumulative lux and effects on fading.
> Back in the old silver days there was that little bit at the bottom 
of a 
> Density/Exposure curve where the toe didn't quite meet up with the 
> Density axis. Silver halides had to get a kick of photons before 
> additional exposure became evenly translated into density of solid 
silver.
> 
> Here's the thing. Do pigments and dyes act in the same way on 
exposure 
> to light? Does anyone know if there is a linear relationship 
between 
> accumulated lux and fading, or is there a toe on the curve whereby 
light 
> energy has to achieve a threshold level before fading begins?. Just 
> curious....
> 
> Whilst we want to nail down all the variables in our longevity 
quests, 
> because we live in different climates, different airborne 
pollutants 
> etc., there is now way that any lab controlled test can have 
meaning 
> apart from providing poor relative guidelines. How can Wilhelm data 
> generated in Europe have any meaning to me in New Zealand?. I sit 
in a 
> humid, ozone depleted atmosphere with little pollution. 100 miles 
away, 
> photographers live in a sulpher dioxide laden atmosphere in our 
> geothermal zones. Common sense tells me that Wilhem tests only have 
> meaning in their lab and it is false assumption to extrapolate that 
data 
> into our individual environments and conditions. Data might be 
king, but 
> only in the room that its sitting in when it comes to this 
discussion.
> 
> I managed to see some of Livicks work methodology before he removed 
it. 
> That guy worked really hard to make sense of his own environmental 
> conditions and make materials judgements based on his findings. 
More 
> power to HIS elbow and less to those who threatened him for sharing 
> those results with the rest of the community. Similarly its up to 
each 
> of us to draw conclusions from our experience. The windowsill test 
is a 
> good start - what's more its free to everyone! The problem with 
much 
> discussion on this list is that at least someone always wants to be 
> absolutely right, absolutely sure.
> 
> John Malcolm
> Love the Light
>