Digital negatives
3 gennaio, 2011 di
Digital negatives
Jon Cone

I created my own digital film system for making negatives, back-lits, and film positives on an Epson R2400 printer.

UPDATE: This system is now deprecated in favor of the Piezography2 Digital Negative and Print System which allows for simultaneous K6 printing and digital negative making without swapping any ink positions.

Where it usually takes several days to create the QTR master curves architecture for a new printer, this took weeks. The problem is that affordable auto-scan film densitometers are not currently available, or it would be easy to release systems for all the current printers. I had sourced a refirbished X-Rite DTP32 for about $1,200. This is a transmissive strip reader that measures only a few densities at a time. I found that in measuring 16 densities at a time, it performs well. But, in creating the initial curves architecture I need to up that to 32 initially, then 64 and eventually 256.

It blows bulbs at that rate and overheats. Measuring 64 patches can take hours waiting for the unit to cool. Obviously, the engineers at X-Rite never anticipated that someone would be trying to make as perfect a linearization as the Piezography process requires.

But, after a few weeks I had a working system. You can find it online at Inkjetmall by clicking on the printer system we support here: R2400R288048007800/9800. But, the curve for QTR is not part of the current QTR download. So, I will post the items and recipe below and even post the curve I made. Within the next few weeks we will have pre-mixed dilutions and kits you can buy for each of the supported printers.

First, I need to explain what a Piezography digital film system does. The concept behind Piezography is a perfect linearization of ink from dMin (the paper white which in the case of a film system is clear film base) and dMax (the maximum ink density.) This linearization produces an incredibly smooth grayscale that has its contrast pre-adjusted to Gamma 2.2. There are no digital artifacts, nor visible ink dots. It is as close to perfection as a grayscale printing system can be.

It does not pretend to know what you intend to do with it. If you are making back-lits you simply print out the film through the QTR curve and install in a backlit box. Presto! Perfection! Perfect smooth linearized tone from clear film to practically opaque black. This is in part my original intention with this system. I wanted to produce prints that were architecturally interesting, looked modern, and were about transmissive light rather than reflection.

The back-lits we produce for people are very subdued as we insert some white density film to reduce the brightness so that they appear just brighter than a traditional print. If the lights in the room are dimmed, they are amazing. The system is being used mostly for offices, and the wiring is being hidden within the walls. It is not an inexpensive process, but is very impressive when installed.

However, if you are making negatives or positives for photographic printing processes – you need to deliver to the system an altered grayscale that reflects the needs of your process. Traditional photo processes require a negative or pos that may not look or feel natural but prints natural. Silver negatives and positives are not perfectly linear and do not approach the dMin and dMax that can this Piezography film system.

For example, in photogravure (which I used to print voraciously from 1984-1992) the needs for dMin and dMax are quite different from the dMin and dMax of the film I can produce with this system. I need a dMin on this positive that is perhaps about 0.32 density. This is the first discernible highlight detail. The dMax for making a just barely detailed black is no more than 1.52. Everyone makes photogravures differently of course. This is just an example. But, the Piezography digital film system produces a dMin that is nearly clear and a dMax that is nearly 2.85.

So I would need to produce an image in Photoshop that the highlight that just prints with detail produces a 0.32 density, and a shadow that just prints with detail at about 1.52. You can use the PDN system at this point. It is very flexible in that it allows you to print out step strips and to find the values you are looking for. You do need to produce the tests into the photographic process you are making film for.

Then you need to create the compensation curve in Photoshop to produce the limited output so that it prints as expected in the process. This Photoshop curve and the QTR curve have no relation to each other whatsoever. The Photoshop curve may actually have to compensate for the “S” curve of the silver process… Lots of curves…

QTR curves are called “curves”, but think of it as a profile for the printer, ink, and media – in this case it’s an Epson R2400, Piezography Selenium inks, and Pictorico Ultra OHP film. This process I produced allows you to print film that is perfectly smooth so that you can define your own process on it according to the needs of your traditional darkroom method.

I can’t really help you with the PDN kit for making your images. But, I have provided you with an excellent output system for film. What you output onto it is up to you! You may wish to source a good used R2400 printer for this process. It prints up to 13″ wide.


Black = Shade 1 = Piezography MPS Black

Cyan = Shade 2 = 50% Piezography Selenium shade 2 / 50% Piezography Selenium shade 3
50% PZK7-SEL-4OZ-2 / 50% PZK7-SEL-4OZ-3 mixed in 4oz empty Nalgene HDPE bottle

Lt Cyan = Shade 3 = Piezography Selenium shade 3

Magenta = Shade 4 = 50% Piezography Selenium shade 4 / 50% Piezography Selenium shade 5
50% PZK7-SEL-4OZ-4 / 50% PZK7-SEL-4OZ-5 mixed in 4oz empty Nalgene HDPE bottle

Lt Magenta = Shade 5 = Piezography Selenium shade 5

Lt. Black = Shade 6 = Piezography Selenium shade 6

Yellow = Shade 7 = Piezography Selenium shade 7

Lt. Lt. Black = PiezoFlush

QTR Curve = NewS9aNG2b-PictoricoUPohp.quad

The above system can be run in a CIS for continuous feed. However, if you run it in refillable cartridges, you can also change out shades 2 and 4, replacing with regular shades 2 & 4, and change out the PiezoFlush for Piezography Gloss Optimizer instead. Then you can print regular Piezography glossy prints! Change back the carts to the film system when you need to print film.

Unfortunately, it would take me a couple weeks each printer model to produce similar systems on other Epson printer models. Time, which I do not have. But, I am in the middle of an experiment with a customer to see if we can adapt the inks and the curve to his printer model which is an Epson 7600. One never knows until one tries. He has the 7600 and has installed the inks. We will soon convert the curve and hope for the best! If its successful, you can count on our adapting to other printer models.

The R2400 negative curve will work on Epson R2880, 4800, 7800 and 9800 models and we will update the InkjetMall website shortly as well as post Digital Negative pages for these printers!
Digital negatives
Jon Cone
3 gennaio, 2011
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