Digital BW, The Print

In a message dated 1/14/07 12:03:15 AM, e.neilsen2@... writes:


> Any print will reflect the light from the conditions that it is in; I have
> yet to see an ABW print made on my 4800 that shows metamerism. 
> 
Agreed...

> I'll have to
> wait until the end of next week to try that image but here is the problem I
> see with that test.
> 
Its one of the images I've tested extensively with, and results with it are 
identical to results from the rather similar ColorVision test image that we 
supply in PrintFIX PRO... no magic here, just a good B&W test image.


>  If you are trying to print a B&W neutral image and you
> are not using a set of Black inks, I doubt that you'd ever get a dead
> neutral print without color in it.
> 
Agreed again, though my goal with PrintFIX PRO 2 was to first allow as "dead" 
a neutral print as possible, then add the necessary tools to tweak that to 
the most ideal ramp from paper white to ink black...


>  Seeing a very slight color in a print to
> me in one light source, and then a radically different color in another
> light, unexpected from the normal shift is bad. 
> 
Seeing a visual shift in perceived tone, unrelated to the appropriate shift 
in media white, when light sources change would be my definition of visible 
illuminant metamerism. That shift which is related to change in media white is 
necessary and unavoidable. I see illuminant metamerism daily in color prints; it 
has basicly disappeared from my life with B&W prints with gray inksets, and 
with the latest "two gray" OEM inks as well...


> How much of what you are
> seeing is ink related and how much is the combination of paper and ink?
> 
That was one reason I mentioned the issue of brighten papers and UV testing 
in my last note: the shift caused by adding UV to the lightsource is pretty 
significant, and on whitened paper it causes major changes in the prints... if 
you don't have a multisource lightbooth with optional UV, it becomes very 
difficult to check for this, as your different light sources may have significantly 
different degrees of UV in them, so that a shift that you think is caused by 
illuminant metamerism, may well be caused by differing degrees of UV. Thats why 
side by side testing of different methods or inksets, ON THE EXACT SAME MEDIA 
would be necessary. Even then, other factors still creep in.

At Photokina two years ago we had an Epson 4000, and a multisource light 
booth. B&W prints from the 4000 were all over the map under different light 
sources, not just in tone, but the densities as well, and UV caused a second set of 
large variations. Two years later at the same show, we had a 4800 and a 9800 
(not to mention a Z3100) and the same light booth. This time the color prints 
still jumped around between light sources, and with the whitened papers jumped 
around with and without UV, but the AWB mode and neutral color mode prints 
were dead stable, under the various light colors, and the bad hall lighting as 
well.

On the other hand, at PhotoPlus in NYC this fall we had a series of canvas 
prints in a gallery at the back of the ColorVision booth. Someone was really 
taken with a shot of an antique Indian motorcycle, and told me that someone on 
the staff had sent him to me in hopes that I might have an art paper print if 
that same image. I showed him a 13x19 print on Entrada, and he frowned and said 
the red of the motorcycle was wrong, way to much of a burnt orange in the 
paper print. I countered that both prints had been made with PFP color profiles, 
(even if in different countries, on different media), so they should be a 
reasonable match. We carried the paper print around the back of the booth, held it 
up next to the canvas under the gallery lighting, and the red magically turned 
red, and was a dead match for the canvas print. Pull it out into show floor 
lighting, it was an unattractive burnt orange again. No fix for that with color 
images but controlled lighting... but when I did the same thing with a B&W 
paper print and a black and white canvas of the same image, there was none of 
that shift.

C. David Tobie
Product Technology Manager
ColorVision Business Division
DataColor Inc.
CDTobie@...
www.colorvision.com


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