Digital BW, The Print

Tyler,

I agree that the "yellow ink causes metamerism" hypothesis is 
unverified and probably false, but it would be difficult to test.  
Metamerism is most apparent in neutral prints so if one created a 
series of neutral profiles with increasing amounts of yellow added it 
would be necessary to also add increasing amounts of cyan and magenta 
to maintain neutrality.  At some point the neutral grays would become 
metameric, but does the metamerism occur because of the additional 
yellow ink or the CM?  I suspect it is the latter but I'm not sure how 
to set up a test to confirm this.  Sepia prints I've made with profiles 
that use only K,LK, LM, and Y do not appear to be metameric but they 
are of course also far from neutral.

Carl


On Friday, September 17, 2004, at 08:31  PM, Tyler Boley wrote:

> --- In DigitalBlackandWhiteThePrint@yahoogroups.com, "weareallsosmall"
> <weareallsosmall@y...> wrote:
>> I remember a thread ages ago that centered around the yellow ink in
>> the 2200, saying that it was the most succeptable to met'.
>
> It may be, but it seems to be an assumption without verification. The
> reason a great deal, if not all, yellow is removed from the various UC
> monochrome solutions out there (like IP) is that the light K ink now
> running all the way up the scale is very warm, and no yellow ink is
> required. Actually, to help metamerism as much color ink as possible
> is removed with these solutions, but some CM (or light CM) is required
> to neutralize the warm light K.
> Someone toying with QTR and UCs could test and confirm if the presence
> of yellow ink increases metamerism.
>
>>  I assumed
>> that prints made with the newest driver for the 2000p were so blue b/c
>> it eleminated much of the yellow ink for the same reason. Whatever the
>> reason, I much prefer prints from the older driver, even with heavy
>> color shift. Most people, as far as I know, only have incandescent
>> lighting in thier homes anyway, so this sounds like kinda kooky logic
>> on the part of epson. Of course I could be totally wrong.
>
> You may be giving Epson too much credit, I doubt much technical logic
> went into whatever decisions led to these results.
> I think Ernst is correct, that the inks just happened to perform best
> under tungsten, then they responded to user complaints with the new
> driver.
> Users are so pesky, looking at their prints under various light 
> sources.
> Regarding profiling for different illumination color temperatures,
> it's pretty common these days. Particularly for work for specific
> installations or exhibits. Still given the lack of sophistication with
> Epson's pre-Atkeson profiling, I doubt they were doing that.
> Tyler