Piezography Digital Negative System Review
August 9, 2013
When printing in platinum & palladium aswell as other alternative photographic processes over time one becomes acutely aware of how critical a role the negative creation process plays in achieving and realising a fine hand crafted print. A great platinum print can exhibit subtleties in the mid and high tone values as well as the darkest shadows areas of the print unlike any other alternative process, having control over these particular delicate tones and how there are reproduced on paper is especially important.
This is one of the reasons why I have been obsessive in identifying the perfect system for creating digital negatives with current technology for my own studio workflow over the last ten years. I have tested more or less every digital negative system currently available for Epson and other inkjet manufactures aswell as Agfa Avantra Imagesetters in the quest to find the perfect system of creating negatives for contact printing. Some have produced excellent results for the time, others are locked in the past produce and inferior results compared to the latest methods.
In terms of inkjet printing the vast majority of users agree that Qtr is the most advanced tool currently available for creating digital negatives. This is in part due to the ability to create custom profiles that allow the user complete control over each ink channel aswell as the ink limits. One of the advantages of such an approach is that the correction curve applied to the original image is generally mild compared to other negative creation methods, this in turn leads to smoother more detailed negatives.
I have been using QTR to create digital negatives for the last 4 years. Overall it is an excellent negative creation system although a few limitations of the rip exist and have been identified when using too few inks (less than 3) when printing high key images, these include banding and venetian blind effect. Previously using more coloured inks in qtr have attempted to solve this issue as Ron Reeder discussed in his article ‘Improved QTR printing’ which can be viewed here.
At the time of him writing the article Ron stated that :
‘Using QTR to print negatives with all seven inks represents the current pinnacle of technology for making negatives with a desktop inkjet printer. When such negatives are used to make platinum/palladium prints on a matte surfaced fine art paper, and are viewed at normal viewing distances, I think the prints rival anything made from an in camera negative. In short, I think we have arrived at the point where we can stop worrying about the quality of ink jet negatives and get on with the primary business of making beautiful, expressive prints’
For me personally having created a number of profiles with 5 and 7 Epson coloured inks in QTR this has led to compromises with imaging artefacts rearing their head again on certain types of images. This could be in part due to the coloured inks I choose for my profiles rather than taking anything away from Ron’s observations.
A natural progression for the QTR rip for creating digital negatives would be replace the coloured inks (which all have differing UV sensitivity ratings) with a custom set of black inks with uniform uv sensitivities and supplied in varying dilutions
I became aware of such an inkset three years ago when master printer Sandy King mentioned that he was investigating Piezography K7 inks for use in creating digital negatives for carbon printing. He had become dissatisfied with all the other digital negative creation options available, due to the unsightly dither patterns that were being reproduced in his carbon prints.
Through his testing he identified that QTR resolved almost twice the amount of detail when compared to the Epson ABW driver mode. Further observations by Sandy can be viewed here
In terms of positive prints Piezography inks are widely regarded as offering the highest resolution black and white inkjet prints when used with QTR and the latest Epson printers. Prints created using these inks are said to be virtually free from dither patterns and artefacts, see here for an example.
My main priority of this testing was to focus on the digital negative aspects of the inkset and workflow however in the process of calibrating the system I created some fine positive prints on Permjet Alpha paper which have a similar dmax (1.5 to 1.6) to the papers i use for platinum/palladium printing.
The underlying principle of the Piezography ink system and workflow involves overlapping inks as shown in Figure 1. Using six or seven shades of Piezography black ink and QTR Rip are said to create higher resolution images with greater tonal separation compared to using Epson’ inks and the Epson print driver.
Figure 1 shows how Piezography inks are distributed along the greyscale and Figure 2 shows a comparison between Epson K3 and K7 Piezography and how the inks are distributed.
Speaking to Jon Cone, the inventor of the Piezography inkset and workflow, the K7 inkset when used with the qtr driver is able to create higher resolution images as result of not needing to dither darker inks to make them appear lighter. Rather, Piezography K7 inks print only with the high frequency dithering which eliminates all paper white spaces between dots, filling that normally unprinted area with printed information.
Setting up and installing the Piezography inks
To prepare a printer for Piezography inks involves flushing out the existing Epson original inks. To flush the printer you install 8 refillable cartridges of Piezoflush ink and work the Epson inks out using a number of power cleans. Piezoflush is an ink formulation that can be used for cleaning, flushing and as a long term storage fluid for inkjet printers. It is stained “pink” so that you can test the nozzle check pattern after cleaning. Once you have a clear nozzle check with the Piezoflush inks you can proceed to install the 8 Piezography Black inks which involves a similar process as the one just described. Figure 3 below shows the refillable inks installed on the Epson 7880, note the other side of the printer has the other 4 inks installed.
It is important that the printer you are wishing to convert exhibits no problems before the conversion, the documentation makes this pretty clear. Clear nozzles checks once the old Epson inks have been flushed and then when the 8 Piezography black inks are installed is essential to have a printer that works reliably.
In my case having followed the detailed instructions provided I got a clean nozzle check both after the piezoflush inks and then after the Piezography inks were installed and have yet to have any problems after two months usage.
For this particular testing I updated my monitor to a self calibrating Eizo. Some people dismiss the importance of calibrating for black and white images however it is particularly important if you want to pre-visualise the entire tonal range including those subtle tones in the higher (85-99%) and lower values (1-15%) of the grayscale. If you can’t see them on your monitor then you have no way of adjusting them. To illustrate this Figure 4 shows a monitor uncalibrated for black and white imaging and figure 5 shows a monitor calibrated to the Piezography workflow. Note the shadow detail in the bottom left and right hand corners of the image, this is detail around the 95-99% which is not visible on an uncalibrated monitor however when properly calibrated this is visible as in figure 5. (Click image for larger view)
Another example is shown in Figure 6, you should be able to view all the way down to 2 or 1 on a well calibrated monitor.
Calibration is especially important for this type of set up, the whole philosophy surrounding the Piezography workflow is about being able to resolve detail and tone in the extreme low and high ends of the greyscale, only at L0 should 100% black be printed. For further information Jon Cone, has written a good article on monitor calibration which can be viewed here. Another useful addition to the workflow is being able to soft proof through Photoshop, Jon provided me with profiles for PS that as it happens were very close to how my prints would turn out once dried down, see here for further information.
Once the system was fully set up and I had achieved Calibration/Linearization for positive prints, Jon sent me the digital negative quad profiles that needed to be installed into the QTR, these had a density range from 1.4-1.8. I printed test charts using all 5 profiles and the 1.8 density profile seemed to be the most appropriate for platinum and palladium digital negatives. Figure 7 shows the User interface for QTR with the relevant profiles installed.
I then created a correction curve for the profile and the resulting step chart is shown in Figure 8. You should be able to see that tone is visible all the way down to 1 % and upto 98%. Previous profiles I had created using other negative creation methods were unable to achieve such accurate linearisation. Figure 9 shows linearisation test results for the Piezography 1.8 profile.
For further information on how the Piezography qtr profiles are created Jon has written an article that can be found here
Testing the Inks
Over the last ten years I have found that the most challenging digital negatives to print in platinum and palladium are either high key or low images which have delicate tones in the greyscale range 1-15% and 85-99%. These type of images tend to show up any problems with a digital negative system as its usually where the least amount of ink and most amount are put down on the transparency film.
I selected a number of such images and printed them using 4 different negative systems; these included the Epson inks with Epson driver (ABW mode, Neutral Tone), Epson inks with Epson Driver (Colorized toning added), Epson inks with QTR and finally Piezography Inks with QTR. Figure 10 shows the negatives for one particular image I chose.
It took a while took get all the different profiles linearized however this was essential for me to see which inkset worked best in my own studio environment. When comparing the correction curves that were applied to each image the curve created using Piezography inks and qtr was the mildest.
Overall when viewing the actual dried down platinum/palladium tests prints using the four differing methodologies, it became clear to me that the prints created with the Piezography inkset and QTR exhibited increased resolution with greater tonal separation in the highlight and shadow areas of the prints. This became more apparent the larger size negatives I created (upto 30×24 inches). Figures 11 to 13 shows scans of platinum/palladium prints created using negatives from the Epson inkset & Epson driver and Piezography inkset and QTR driver. To view the images properly, click the image, this will open it up as a higher resolution version. The images should also be viewed on a properly calibrated monitor that is able to show tone down to 1 in figure 4 above.
Having tested the Piezography inkset and workflow for two months a couple of limitations exist for those wishing to migrate over to such a system. The first being that you are fixed to a particular tone of inkset for positive printing, in this case I tested the selenium tone inkset, as I rarely print positive prints this has not been an issue. (I will be testing the neutral warmtone sets for digital negatives at a later date.) The other is that the negatives created with the Piezography inks are slightly more fragile compared to those created with the Epson inkset and driver. As a previous user of large format in camera negative film I learned to be very careful when handling negatives and as such, one should adopt a similar practice.
Taking these limitations aside I have been impressed with the Piezography digital negative system and it is now one that I currently use on a daily basis. Of all the negative systems I have tested over the years this method has created the finest looking platinum/palladium prints to date. I will create a follow up post after using this workflow for 6 months.
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