Piezography BW - PRINTING ON UNSUPPORTED PAPERS
Please report errors or omissions to Bill Bergh - bill@cone-editions.com

Many of our Piezography BW users have never had the pleasure of the manual quad-black printing struggles of a few years ago. The Piezography driver was developed to solve or make transparent the many difficulties we all faced trying to print good Black & White images with a mixture of four dilution's of black inks.

Some issues that the Piezography BW driver addresses:

1 - TOTAL INK LIMIT
One of the original problems with the Epson driver was that it contains a total ink limit that was tuned to their inks and papers.  We experimented with a 3000 and colored inks by doing a double print, and it was drop dead gorgeous - but of course out of registration.  We tried taping on tractor holes to some art paper and running it through twice - but gave up as there was never a way to get the second print exactly positioned.

When you do CMYK printing through a RIP to the Iris printers, the amount of total ink is determined by the user.  Tests must be made on each paper to see how much ink the paper (and any coatings) can carry up to the point that the ink begins to mottle and bleed.  The amount of total ink the paper can carry differs from paper to paper.

The Piezography BW driver Piezography puts this control back in the hands of the user.  If you truly desired, you could print up to 400% ink and watch the ink drip off the paper.

2 - TRUE FOUR CHANNEL CONTROL
Second, you need to gain control of all four channels independently, and this is possible by using RIP software.  Most good RIPs are very expensive, so this is not an affordable option for most and is not offered for many desktop printers. The Epson driver basically is a 3 color RIP.  When you print a greyscale gradient, the Epson driver will dither CMY together up to a certain point and then switch to the black ink.  There is no true black plate, and you lose all control of the black ink, that is offered by true 4 channel RIP software.  No shadow detail is discernible after the point where the black ink cuts in.  The older printers (Epson 3000) tend to block up all shadow detail after about 85% black.  Epson has greatly improved their driver and the more modern printers are much better, with maybe the last 5% to 8% lost as pure black.

3 - DIFFICULT WORKFLOW
A few years ago, when people began experimenting with a manual quad-tone process, they had to purchase some kind of four channel RIP software, duplicate a greyscale image into 4 channels, and then work in Photoshop in CMYK mode without a preview.  Actually you could preview the image, but it would be in ghastly rainbow color.

Before you began printing any images, you would first start out with a series of step strips, a strip of small boxes created with very specific percentages of ink varying progressively from the white of the paper through to full black.  You could make up strips with 5% increments or even smaller steps if you were zeroing in on a problem area and trying to blend inks to eliminate a problem.

You would then develop your own set of 4 curves to control the quantity of the ink printing the 4 channel separation.  As you worked out a set of 4 curves - you had to deal with :

1 - How much total ink can a paper hold with out bleeding or mottling?

2 - How much of each ink can be printed before an increase in the amount of that ink yields no darker value?

3 - How do the inks mix and what percentages can you print of various combinations before they mottle and bleed?

4 - How to blend the inks as you transition through the value scale of one ink, and must change over to the next density of ink to continue printing progressively darker?  These crossover regions were the most tricky of all, and a good deal of time was spent here on this part of the process.

This is just a hint at the struggles we all were going through a year ago to do good B/W printing.  When you were finally satisfied that you had worked out all the problems for a type of paper, you could now begin to start printing images, and begin to learn what sort of image manipulation was required to take advantage of the new workflow.  If you wanted to print on a different kind of paper, you had to start all over and develop another set of curves.  Not for the faint of heart.

PRINTING ON UNSUPPORTED MEDIA USING PIEZOGRAPHY BW
To help automate all this, the Piezography plug-in lets you work in a single channel greyscale (hint: file size is 25% of CMYK) - does the four channel separation for you, and we provide the 4 curves in the form of an ICQ profile for the papers that we have profiled.

When you switch to another paper and try out our canned paper profiles, you should realize that you are now in "EXPERIMENTAL MODE".

We knew that we could never cover all the media that people would want to print on.  For example there are people printing on "T-shirts Transfer" material, and others printing on transparent media to use the prints as large format negatives for contact photographic printing.

For this reason the profile list contains a selection for an "unsupported" media type.  This produces a predictable linear 4 channel separation of the image, which can be a good place to start experimenting.  The driver also has a  dot density control - which lets you vary the total ink and a gamma control that allows you to apply a curve adjustment to achieve a good the mid point. You don't necessarily have to start out with the unsupported media setting, if one of the canned profiles is a pretty good match to the new media.

The intent was that the user could then create a final adjustment curve in Photoshop, to fine tune the printed image.  Photoshop allows you to save that curve - so that it can be loaded for future images.  Name the curve with the name of the paper, so it will make sense later when you load the curve prior to printing. This kind of work is best done with test strips instead of images - because you are trying to tune in a paper and it is better to approach that scientifically.  Once you can print a 21 step strip well, you will have good results with your images.

When you move into unsupported papers, you should know you are now stepping into the area of experimentation, and you should expect to have to do some work to get a good print.  Piezography gives you the tools to do that.  It sure beats having to buy RIP software and having to work in CMYK with a multi-hued rainbow preview.

Most people try a shortcut.  They get a new paper, and then tryout the different "canned" profiles, and find one that best prints an image.  This is OK - but the profile may not be accurate for the paper, and a different image on the new media may print poorly.  Printing a 21 step strip would have made this obvious.

Typically problems with this method will be flat posterized areas that show up in some images.  This is not a flaw of the system, but the incorrect application of ink.  The cross over regions may exhibit problems.  People choosing this workflow should be aware that using a "pretty close" profile may not be perfect for some types of images.

Or in other words, when you are in "EXPERIMENTAL MODE", expect to do a little work to get the best out of the system.