I have asked this before, but somehow I keep seeming to circle back, it’s never been completely resolved in my mind. Was wondering what other users advice is…..
My understanding is QTR will always expect/demand files to be at 720ppi (because ‘finest details’ is turned on in the background). If it receives files that are not 720ppi, then it (QTR) will add the pixels (resample the file) to get it to 720ppi.
If that is the case, then it seem to me preferable to resample the file in Photoshop before sending to QTR, because at least then I can choose the algorithm used for the upsizing (Preserve Details 2.0 or Bicubic Smoother usually).
But the advice that I have received previously, if my memory is correct, is to not bother about setting the ppi to 720 but just send the file as is and let QTR handle the resampling? Is this still the current advice?
As per my question above, what is the current advice from IJM regarding resampling (up or down) files before sending to QTR? Is it better to add/subtract pixels in Photoshop or to just send the file as is?
Great question! I am sorry I missed it in your original enquiry. It sounds like you’re diving into the details of print resolution, and that can make a difference in the final output.
When the QTR software prints at 2880 uni-directional, it’s laying down ink at a very high density—2880 dots per inch. This high dot density, combined with our Piezography Pro inks and .quad files, creates a stunningly sharp image. It becomes very difficult to see individual pixels, even when the original file is at a lower resolution such as with iPhone photos at 100 ppi. They print surprisingly well. This is because the printer’s high dot density with so many overlapping ink shades helps fill in the gaps and smooth things out, making a low-resolution image appear better than you might expect.
Your question about resampling is a great one. When you resample an image up, you’re essentially adding new pixels to the file. The quality of these new pixels depends entirely on the software’s algorithm. Tools like Gigapixel use very sophisticated algorithms to guess what those new pixels should look like. You can fine-tune these settings to get the best possible result - and you can do side by side print comparisons to find your fav settings. However these algorithms are often dependent on the the type of image file you are supplying.
So, what should you do? My recommendation is to test it out. Print your original files at their native resolution first. Then, try resampling them with a tool like Gigapixel and print those versions too. Compare the prints side-by-side to see if resampling is adding to or subtracting from the final print quality in your opinion.
Generally, we never recommend reducing the resolution of an image, and we believe there’s no such thing as too much optical resolution—the resolution of the original image before any resampling. Piezography print quality is superior based on the many overlapping curves of ink produced by our .quad files. What is considered best practices on EPSON driven prints often does not apply to Piezography driven prints.
If you have any more questions as you run these tests, feel free to ask.
In the past, when I have tested sending files at their native resolution vs resampled files at 720ppi, my conclusions were that the native resolution files seemed smoother and softer, while the resampled versions did seem marginally sharper with more resolved detail.
I was just revisiting this subject wondering if there was consensus from IJM or users as to which approach was prefered
Neil I am just now considering this subject as I recently got my Pro ink setup in a 3880. I’ve read the Epsons have a native resolution of 360ppi versus a canon at 300. I’ve tried both and I’m very hard pressed to see any difference, even with a loupe. Haven’t tried 720 yet, all my older files can’t support that rez even at smaller print sizes without upsampling. . Have you seen an improvement going to 720 over say 360? You mentioned some results you’ve gotten with native at 360ppi and upsampled and printed at 720, which did you ultimately decide was best for you?
Mike
Hi Mike. My understanding is that Epson driver insists on a file that is 360ppi. If you send a file that is any other resolution, the Epson will change the ppi, either up or down, to 360ppi. If you turn on Finest Details in the Epson driver then the printer insists on a file that is 720ppi, and the printer will resample any file to 720ppi. The Finest Details switch is on by default in QTR/PrintTool, so any file sent to the Piezo system will be automatically resampled by the driver to 720ppi. My preference is to do the up-or-down resampling myself in Photoshop, where I think I have better control of the algorithm used to add (usually) or subtract pixels to get the file to print dimension at 720ppi, rather then letting the Epson driver do the resampling. That is my understanding, but it’s a slippery topic somehow and I have heard different theories and different understandings
I wouldn’t be too concerned about what the ppi is for Epson since Piezograghy is printed through QTR (windows) or Print tool (mac) anyway. Canon is a nonstarter anyway since the ink is only formulated for Epson printers.
Thanks Neil and Keith. It actually wasn’t a topic I had thought much about, but the original post brought it to light for me. I’ll experiment a bit I guess. I didn’t realize QTR was resampling to 720, good to know. I’ve been printing small so far, I’m still under my native file resolution. When it’s time to upsample I see I’ll need to pay more attention to this. Mike
My understanding is that QTR and Print Tool are built on top of the Epson driver. It’s essentially the Epson driver with some added controls. But it uses the native Epson dithering pattern. So the ppi requirements for files are still the same as for any Epson printer. I would love to be proven wrong because it’s consideration always having to send 720ppi files to the pipeline when printing Piezo.