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Author Topic: Printing B&W prints in Color Mode gives better result the ABW mode on Epson 9900  (Read 6748 times)

ecmjazz

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Hello,

My print provider has been printing so far only in color mode even neutral black and white photos, so I asked them to try ABW on one of my photos. We used no color toning in the ABW settings, and the Tone setting was set to Darker, quality - the highest possible, one-directional, all other settings set to default. The result was that we obtained a photo with visibly lower density in the shadows, worse contrast in the midtones, and a subtle, but still noticeable bluish overall tint. We ran the same photo through the color mode, and it had more density in the shadows, better midtone contrast, and the bluish tint was almost gone. We did the same on both Photo Rag Pearl and Fine Art Baryta. On the Fine Art Baryta the differences were not so big in the color tint, but still noticeable in terms of density and contrast. On Photo Rag Pearl the color difference was more noticeable than with the Baryta tests. Do we miss something in the ABW settings? The second question is - is it possible that the bluish tint is actually not there, but it is just a psychological effect from the yellowness of the paper, that's why the greys of the ink shift at its complimentary color in the blue tonality? The latter could explain why the more-yellowish Photo Rag Pearl shows more of the bluish tint (it shows some even in the color mode print). As a further proof of that idea is the fact that when I put the print made on Photo Rag Pearl made in color mode, which still had some very fine blueish tint, under a 10 cm.-wide natural white matte, the bluish tint "disappeared", which may be caused by the fact that the eye/brain adapted to the white point set by the matte. Then the question would be - if one would like to achieve more neutral black and white print on Photo Rag Pearl, would it help to pull down slightly the blue channel in the initially neutral file where it was R=G=B initially, so it will print warmer, and thus appear neutral on the warmer paper? Of course that can be done only in color mode, and maybe is not needed if using such a matte, but still the question is interesting. Is it possible also that actually the ABW mode created a print which is technically closer to the neutral, but that to be the exact reason which lead it to actually look more tinted on the papers (especially on the more yellowish Photo Rag Pearl), and on the other hand although the color mode has provided a technically less neutral print, it worked better with the paper, and thus seemed more neutral to the eye/brain (again especially with Photo Rag Pearl)?

Thanks in advance!
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digitaldog

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The second question is - is it possible that the bluish tint is actually not there, but it is just a psychological effect from the yellowness of the paper, that's why the greys of the ink shift at its complimentary color in the blue tonality?

Very possible, depending on the degree of OBA's in the paper and how the print was viewed.
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Alan Goldhammer

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I've done a comparison of ABW vs Color managed with Museo Silver Rag and see little of the difference you note.  I don't see any blue tint on the ABW print at all.  I use ABW profiles prepared using Roy Harrington's QTR program (I'm on Windows 7 and can still do this).  On the color managed print I use my own prepared profiles which include a 51 step B/W wedge to improve the fidelity through out the B/W range.

Alan
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NeroMetalliko

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Hello,
I have used Photo Rag Pearl and Photo Rag Baryta during my linearization test made using  an Epson R3000,
what I could tell you is that in nine months of full specific B&W research/development and test
for each paper (including the matte ones) I have always measured higher dmax, better neutrality and better linearity in ABW mode vs the color mode, always.
For this reason what you have observed should not be considered normal in my opinion.
Regarding the "impression" of bluish grays on warm papers I can confirm you that a truly neutral gray ramp may absolutely appear a little bit "cool" in the midtones/highlight transition up the not inked paper white color.

To have the objective confirmation if this could be an illusion or not the only way is to print a gray target strip
(18 or 21 patches are more than enough) in both the modes and measure it with a spectrometer.
Looking to the graph I usually make from these measurement any color cast or non linearity will be easily recognizable.

In this way I have recently discovered a bug in the Argyll "chartread" exe  
as described in these threads:
http://www.luminous-landscape.com/forum/index.php?topic=82133.0
http://www.luminous-landscape.com/forum/index.php?topic=82171.0,

The bug is affecting the ColorMunki readings in strip mode
and resulted in a not neutral black point inside the final paper icc (Photo Rag Baryta in this case).

Note that this bug is still currently present in Argyll version 1.5.0 and 1.6.0 (but not in 1.4.0)
and will hopefully be fixed soon in a new Argyll release
(I have already tested some working beta fix kindly provided to me from Graeme Gill for this purpose).


Back to the topic,
Just to see what I mean,
in attachment you can find 3 graphs of a 18 step wedge gray scale,
one was related to the canned Hahnemuehle ICC for Photo Rag Baryta 315,
one was related to a custom Argyll 1.6.0 ICC made of 840 patches (including 64 grays) for the same paper
the latest was related to ABW mode (neutral dark settings) still using the same paper.

- As visible the canned ICC is the less linear but is still no slouch from neutrality point of view
- The Argyll ICC one is more linear and really neutral from L* 30 up, confirming that Argyll is very capable system,
but is flawed from the mentioned measurement error producing an evident cast starting from L* 30 toward black (which is very purply).
- The ABW is the most linear and neutral of the three and showed a stronger black (L*=3.2 instead of 4.7 of the two ICC).

This is useful to show that, if you have a "real" gray cast somewhere, you will easily discover it in this way.

Any comment is welcome.

Ciao.

Andrea :)





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