Digital BW, The Print

Bernd,

You wrote:

>...I had the opportunity to visit a  famous and very
>experienced master photograph/ and - printer ... He made a
>lot of IRIS prints, which in general have got bad color shifting
>over the years.

Some of the people in the galleries I looked at also seemed to say the Iris
had gotten a bad reputation.  I wonder if it is the same warming that we are
seeing in the current pigmented quads.

>So he switched to archival inkjet printing. He first
>used Cone inks, now he uses MIS inks too.
>When he showed me his portfolios I was not able to tell Piezo
>and MIS apart.

There could be a number of factors that explain the differences in the
colors of the Piezo and MIS prints we've compared.  First,  it appears from
what you say that the Piezo prints are older than the MIS prints.  From what
I can tell, the green in the Piezo light midtones is a dye that fades
quickly.  In my fade tests, the Piezo turns brown and looks more like the
MIS after it's been exposed to light for a while.

> Each print could stand alone in its beauty.

Color is very subjective.  Also, it is mainly when prints are held
side-by-side that I notice the differences.  I am a silver printer, so I
have been most interested in getting to a color that could hang next to my
silver prints and look consistent.

>To my eyeballs and in direct comparison the MIS inks had a
>slight greenish tint, while the Piezo prints had a slight brownish
>tint.
...
>(BTW all prints are made on Hahnem\ufffdhle German Etching=Orwell).

In addition to the age differences, the paper is probably a factor.  Also,
have you noticed the comments in the Piezo list about green colors?  I think
that different ink batches may have different color tints, or the
dyes/pigments might be separating.  I've noticed that with my Piezo CIS, I'm
getting different densities now than I used to, although I don't think the
colors have changed.

So, bottom line, I can't be sure what is causing the variances or
differences.  However, here are the R/G/B readings I get with Piezo and MIS
Archival Matte test strips (essentially the same age and stored in the
dark), reading the midtone values from 20% to 80% using the Photoshop
Histogram tool and an Epson 1600 scanner:

Piezo R/G/B/ = 140/143/132

MIS R/G/B = 132/129/121

I think that these readings are consistent with my subjective observation
that the Piezo Archival Matte test strip has a slight greenish tint.  The
green reading of the Piezo test strip is elevated.

So, I suspect we are just seeing differences due to age, inkset batch, paper
type and batch (I've noticed some differences even between different batches
of the same paper type), and probably other factors.

Again, however, these differences are mostly noticeable when the prints are
held side-by-side.  I have straight MIS prints, silver prints, and Piezo
prints all hanging within my view, but in different rooms and/or lighting,
and they all look fine.  Most don't notice any differences where the prints
are on different walls.

Paul
http://www.PaulRoark.com