Why don't Hahnemüle papers trigger out-of-gamut warnings when softproofing in Lightroom (when Canon Matte Stock does)?

Question

I recently bought a Canon Pixma Pro 100. To get a better understanding of stocks, I have been printing the same (black and white) image with the same sharpening etc. on lots of different papers so I can accurately compare stocks side-by-side.

Softproofing Canon's matte offerings in Lightroom using Canon's print profiles, I can see there is a huge chunk of tonality out of gamut for Canon's cheap Matte Photo Paper, and still quite a large chunk of the shadows out of gamut with Canon's more expensive Photo Paper Pro Premium Matte. Using intent: Perceptual, I have still managed some decent prints with both papers, and unsurprisingly Canon's more expensive stock gives a nicer print.

Today I received a sample pack of matte papers from Hahnemühle. I downloaded the profiles for the seven different papers included, and was immediately surprised when softproofing to see no gamut warnings at all for any of their stocks. Yes, the papers are lovely and the prints are looking great, but my question is this:

Do Hahnemüle's papers actually support such a broader gamut than Canon's premium paper? Or is this a case of clever marketing (meaning are their profiles tweaked to not trigger gamut warnings somehow)? I found it strange that none of their varied papers - including rag, rice-paper and canvas – triggered out-of-gamut warnings when softproofing. Is it just the case that Canon's product is much inferior, or is something else going on?

Answer 1

Out of gamut warnings have no well defined meaning using Perceptual Intent because all possible colors are supposed to be mapped to printable colors and compressed near the gamut boundaries. Ideally, the profile Perceptual tables can invert the printed color values to produce the originals.

Out of Gamut warnings are meaningful with Relative and Absolute Colorimetric intents because the specified color is printed so long as it is in gamut. If it isn't, the nearest printable color (usually based on delta E) gets printed. The Relative Col. tables in the profile then report back to the application the actual color printed. At least within profile, instrument and printer variance. When this actual differs from the requested color by an amount determined by the application, it may activate out of gamut masking or flagging.

However, How Perceptual tables in profiles are constructed is left to the profile designer and there are some major differences amongst printer OEMs. Canon normally does not perfectly invert Perceptual tables but instead, reports back the colorimetric value printed. Most other OEMs and profile software makers invert perceptual tables along the neutral axis.

As an example, Canon profile Perceptual tables can report back a L* value of 17 when an RGB value of 0,0,0 (black) is requested while a profile made by X-Rite or another paper supplier will almost certainly report back an L* of 0. Both actually print with a black at L*=17 in this example.

When printing using Relative Colorimetric, there is much more consistency between profiles from different vendors.

Answer 2

Wild guess.

I notice that the Canon stock is available with a baryta [stipulated] base coat. Other words mentioned between the two sites are "optical brighteners."

I would say that the sub-emulsion paper coatings and optical brighteners that are different between the two paper stocks are a possible explanation for the difference.

The Hahnemüle site also stipulated that their gamut profiles exclude any raster image processor interaction which might be another possible explanation.