I've been pouring through the Piezography site at the same time as reading through some basic introductory stuff - probably not a great idea. Anyhow, although one must keep in mind the Piezography material is trying to sell you something, I am intrigued by a few things. It is also alluring specifically because Cone seems to personally be very into detailed low values. This is extremely important to me. But I'm slightly off topic here.

What I really wanted to do is run my very preliminary understanding of the overall issues of linearity and calibration by everyone to see if I'm even roughly on the right track - keeping in mind I don't yet know much about the various steps in a digital workflow and am struggling with the computer lingo. I'll do this by way of analogy with "analog"/darkroom tone reproduction.

In analog, one way of studying tone reproduction is the well-known 4-quadrant diagram. Essentially what we are doing is tracking the original subject luminance values as they transition from step to step in the workflow, and ultimately map to print values. For a given scene and chosen set of materials, the transitions in the 4-quadrant diagram represent what is imposed upon us, and each is a non-linear function:

1. Flare curve
2. Film curve
3. Paper curve

In the context of a hybrid workflow where we are scanning B&W negatives, items 1 and 2 above still apply, but item 3 is replaced with two new, potentially non linear (or worse, non-linear and choppy) transitions – scanner/scanning and printer/printing.
In the analog workflow we use printing controls to produce an expressive print with the tonal relationships we envision.
In the digital/hybrid realm, “editing” in Photoshop or similar – I think – is analogous to printing controls in the analog/darkroom realm, and that we ideally want those controlled edits to be the only transition between the negative and the print. For that to be the case, we want the scanning and printing transitions to be linear. In other words, the scanning and printing (printer) transitions should not apply tonal relationship changes of their own. Since scanning comes before editing, we can live with some distortion and correct it implicitly in editing. However we are still left with the printer.

It seems to me what we are basically talking about in Piezography (besides grey scale hues, selective toning, d-max, archival concerns etc.) is modifying the printer/driver so that this final transition is linear – ie it does not introduce any curves of its own to distort the tonal relationships we finalized in editing. My understanding is that this fix is essentially what a “profile” is.
Further to this, a calibrated display is desirable so that, assuming we achieve linearity at the printing stage, what we saw in the editing software is as close as possible to the printed output.

I suppose my first question (knowing little about computers/software) is – why, after all this time, do we need to jump through hoops to get linearity from the printer? I understand the B&W linearity problem arises at least in part from printers/drivers being optimized for colour printing, but it just naively seems to me this should have been solved by now. Related to this, I’m having trouble understanding the nature of banding, and how Piezography profiles get rid of that. To be continued.

Anyhow, just some thoughts.