More inks = bigger gamut volume... but what other benefits?

[gkroeger]

My question is a more general formulation of a previous question about the new Epson SureColor P6000 vs. P7000, but it applies as well to the new Canon iPF ProGraph printers as well. Is gamut volume alone the only benefit of a larger ink set?

While it is easy to see the larger gamut volume that the larger ink sets provide, that additional volume encompasses only highly saturated colors at the outer edges of the gamut. But surely the gamuts of all printers have gaps and holes within the volume representing colors that are hard to achieve with the quantization from a finite number of inks and nozzles. Do the additional inks (green, blue, orange, etc) also help "fill in" these gaps within the gamut volume?

The reason I ask is that it would seem that the highly saturated colors around the extremities of the gamut volume are seldom encountered in many types of photography. While I can see these colors appearing in images that include fabrics, flowers and painted structures, it would seem like many portraits and landscapes would have few if any of these highly saturated colors. Yet I read comments that printers with larger ink sets often produce smoother and more natural skin tones. Would extra inks, for example, be of any benefit in reproducing a sunset image with smooth gradients of pastel colors?

Any informed comments and personal experiences would be helpful as I try to decide whether a few extra inks would be of any benefit to my prints, mostly landscapes without flowers.

Glenn

[aaronchan]

My question is a more general formulation of a previous question about the new Epson SureColor P6000 vs. P7000, but it applies as well to the new Canon iPF ProGraph printers as well. Is gamut volume alone the only benefit of a larger ink set?

While it is easy to see the larger gamut volume that the larger ink sets provide, that additional volume encompasses only highly saturated colors at the outer edges of the gamut. But surely the gamuts of all printers have gaps and holes within the volume representing colors that are hard to achieve with the quantization from a finite number of inks and nozzles. Do the additional inks (green, blue, orange, etc) also help "fill in" these gaps within the gamut volume?

The reason I ask is that it would seem that the highly saturated colors around the extremities of the gamut volume are seldom encountered in many types of photography. While I can see these colors appearing in images that include fabrics, flowers and painted structures, it would seem like many portraits and landscapes would have few if any of these highly saturated colors. Yet I read comments that printers with larger ink sets often produce smoother and more natural skin tones. Would extra inks, for example, be of any benefit in reproducing a sunset image with smooth gradients of pastel colors?

Any informed comments and personal experiences would be helpful as I try to decide whether a few extra inks would be of any benefit to my prints, mostly landscapes without flowers.

Glenn

One of the advantage of using extra ink besides CMYK is to produce smoother color gradation.
Let's say if the printer has Green Color, and the image contain a certain green, the printer will use the Green Ink as a major base and use others to build the rest.
But if you print is a CMYK printer only, that mean the whole entire green will need to mix Yellow and Cyan to be created.

aaron

[Ernst Dinkla]

It also depends on what the manufacturer considers as important. For example in the HP Vivera Pigment ink set of the Z3200 the black generation is heavy, in other words the composite mixes of more hues to create grey is at an absolute minimum when neutrals are made. To keep the greyscale smooth 3 to 4 grey inks are then used and the PK + grey inks are neutral by themselves (the MK black is warmer though). Similar substitution happens in the color mixes with the extra RGB inks replacing mixes of cMmY though mainly in the saturated areas, nowhere near the grey spine of the gamutvolume the RGB inks are used. With carefully selected pigments this color mixing method can reduce metamerism and create a better light resistance.  Then there is the extra gloss enhancer to reduce the gloss difference etc on glossy papers. The gamut is not the widest available right now, I think HP aimed at longevity + a good gamut.

Met vriendelijke groet, Ernst

http://www.pigment-print.com/spectralplots/spectrumviz_1.htm
December 2014 update, 700+ inkjet media white spectral plots