Piezography Curve Adjustment Tool
12 septiembre, 2016 por
Piezography Curve Adjustment Tool
Jon Cone

In early March of 2016 we introduced our new digital negative system we call PiezoDN. Along with its amazing ability to make digital negatives for any darkroom process, we added a small tool called “The Piezography Curve Adjustment” tool. We had created this tool internally for Platinum negatives because we needed a way to limit the density of the second-to-most dense part of the negative so that PiezoDN could print onto ANY darkroom surface perfectly while also printing a full-white in the lightest areas. Now we are releasing the tool as part of the new Piezography Professional Edition package for Piezography users not just PiezoDN customers.

If you print with a linear Piezography quadtoneRIP “.quad” (also known as curve or profile) and you feel like the final print still needs adjusting to match your monitor, this little utility will help you! Instead of tweaking your monitor to match your print, you can simply add an adjustment into the Piezography .quad that changes the contrast of that .quad so that the final printed tones match your monitor.

You do this by opening the image you just printed and adding a curve to the image like you would to adjust the final print after a first proof. The only caveat here is that you can only add 4 data-points to the curve (not counting the top and bottom which you don’t change). Then, instead of printing this edited image, you open the Piezography Curve Adjustment Tool in Excel and copy the 4 inputs and 4 outputs from your Photoshop curve into the input/output columns in the tool as seen above. Then you go to the next sheet called “CGATS” and copy this sheet into a new .txt file.

The tool has some really unique algorithms inside it that will turn this curve into fake measurement data. This data can then be combined with the original .quad that you want to adjust by using the new QTR-Linearize-Quad droplet found inside of your QuadtoneRIP folder.

You select this .txt file with the fake data along with the .quad and simply drag both files over the QTR-Linearize-Quad droplet. A new “-lin.quad” will be made and this is the adjusted one. If you install and print with this new curve it will print with your Photoshop curve adjustment!  This way you can custom-tune your Piezography environment to more closely match your monitor without having to add an adjustment curve to each file that is only used for printing Piezography.

Other uses for the tool are to match Piezography to other processes like Epson’s Advanced Black and White driver. In this situation you would print a 21 step target and measure that in with a spectrophotometer like a ColorMunki or Spyder. Then you would put this data into the new Piezography Linearization Checker that comes with our free Community Edition archive. This gives you a visual “curve” of the out-of-linear characteristics of ABW, that you can match in Photoshop and then apply to a linearized Piezography curve. In this way you can print flattened images that have already been adjusted for ABW but that you want to print at a higher quality with Piezography. You won’t have to add a new adjustment in Photoshop and risk a decay of valuable image bit-depth!

One caveat to this workflow: it’s important to keep both the linear curve and the .txt file around. To re-linearize you will need to do this with the original “linear” curve and then re-tune that new linear curve with the saved .txt file!

There are many different things that you can do with the Piezography Curve Adjustment tool. We hope it’s valuable for your artistic process. Full documentation and download is available with the Piezography Professional Edition.

Piezography Curve Adjustment Tool
Jon Cone
12 septiembre, 2016