Using L* values to Validate Linearization


#1

In a recent post, I got a reply that dMax L*>20 is an indication of an inaccuracy somewhere in the process. Question 1: Is there a chart that shows what L* should be for the various papers? I’m thinking of at least a dMin and dMax value. I’m looking for something to use as a guide to know that I have accurately printed the target and that my ColorMunki is calibrated and performing well. The Linearization process consumes many hours of tedious work, and now I have 5 papers to linearize for a second time.

My re-do on Linearizing Canson Rag Photographique resulted in 13.0<L*<13.7 for each of the three curves. I somehow got 20 on a few of my previous linearizations.

Question 2: Is there a way to view the original curves that you include with PiezoPro? If so, I could verify that my data is close and that my process control is adequate.


#2

For matte papers the L* will be between 12.14 and 16.7.

For gloss papers the L* will be between 1.9 and 6.6.

 

You can open the curve in “CurveViewer” located in >Applications>QuadtoneRIP>

 

best,

Walker


#3

Thanks.

 

What papers has an L* approaching 1.9 and 12.14?


#4

Hahnemuhle Photo Rag 308 and Hahnemuhle Bamboo are in the 12.14 range (dMax of 1.85) with pro inks but this is really specific from printer to printer. A different printer of the same model might print 12.86 L* on HPR308. 12.14 was the latest L* registered at Latitude in Chicago. We have seen 12.65 or higher at Cone Editions.

Ilford MonoSilk and Harmen Fiber Gloss Baryta both get in the 1.9 L* range but varies between this and 2.7 from printer to printer.

Long story short, for matte paper, Pro ink is just vastly vastly (industry leading) darker than any other ink out there that has ever existed. On the gloss end it’s matching the most recent Epson ABW dMax from the SureColor printer (all be it with more separation and less compression of the shadows dues to linear printing which simulates a visually darker black).

best,

Walker


#5

I think it is worth mentioning that your choice of the “Paper Type” at the printer console when loading your paper may also affect DMax since the Paper Type setting affects ink loading within the printer itself (and also other things like Platten Gap, Paper Suction, etc.). (Since QTR does not allow you to specify any kind of “media” setting like the standard Epson driver which overrides the printer setting, the settings at the printer itself will apply when printing with QTR).

To select the best Paper Type you start with what the vendor recommends, though in some cases, especially for non-Epson papers, I have found that a different setting can produce slightly better dot smoothness and even DMax. Canson fairly recently changed their recommended Epson Paper Types for all their papers, and I think the new recommendations are better than the old ones. (For example, they now recommend Velvet Fine Art rather than Enhanced Matte for papers like Rag Photographique.)

FWIW, Dave