Digital BW, The Print

Hi.

 Y'all are talking about the things I asked about the other day  and
got no response on. Oh well, I'll take info any way it comes.

 Don't know about the i1/xrite construction differences but assume
that you mean one has uv filering over it's illuminant source while
the other does not. In either case I wouldn't think there should be
any difference between them as regards visible blue. That is, unless
the xrite is actually cutting off more than uv. Given that, the
differences have to, IMHO, be due to what Greg said, flourescence in
the visible range due to uv excitation of the paper OBA from the i1.

 Something I haven't heard about here to date is the possibility of
light piping via the paper substrait/coating in a brightly lit room.
That includes uv effects if it is present in the area.

 It does occur.

 I learned that the hard way recently while tinkering with a DIY
colorimeter. It was fluctuating cyclicly with time of day at the
density extremes but only at certain spectral points. It turned out to
be sensitive to both of the above effects. In the course of
determining this I played with several papers known to have
substantial OBA content and some I didn't know about but quickly
learned. One of the papers was plain old ordinary cheapo Epson Photo
41141. It turns out that this flouresces like crazy as blue green with
green slightly predominant. Moreover it continues to do so with slowly
declining output for some time after it is placed in the dark.
 Something like that is highly likely to impact almost any instrument
to at least some extent.

Regards
Duane




--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "Greg"
<dfaprinting@...> wrote:
>
> --- In DigitalBlackandWhiteThePrint@yahoogroups.com, Carl Schofield 
> <scho@> wrote:
> >
> > I agree.  The prints look dead neutral to me and I don't see the 
> cold  
> > hue that is suggested by the i1 readings.
> > 
> > Carl
> 
> Must be your vision adapting to the different "white point", you might 
> see it if you have some no OBA paper to let you vision adjust to, and 
> then compare the print to that non OBA paper. Best if viewed in 
> sunlight.
>