Question. A large number of settings exist under the Blue Gear icon (Qimage Printing Options). I read the Help and watched the video. The Interpolation for Normal Prints shows the max of "Overdrive 1440 PPI", but AI has never selected this setting. I'm printing with the ET-8550 which is capable of a "Maximum Print Resolution of 5760 x 1440 dpi." My images are shot with a Sony a7IV which has a resolution of 7008 x 4672 ppi. AI has always selected/defaulted to the Max 720 PPI. Should I be using 1440? Clarification, please. Thanks!

Fred has the answer with regard to driver PPI.  But what you are talking about (Qimage's interpolation resolution) is not a driver setting so Driver AI does not apply and Driver AI will not change that setting.  So you can select any "Res" you want in Qimage, Driver AI is still going to set the driver to the highest quality (720 for an Epson).  You could even set Qimage to 360 if you like: Driver AI won't touch that because it isn't a driver setting and will still set the driver to its highest "Quality" setting, usually 720 PPI for Epsons.

Regards,
Mike

That depends.  Your 7008x4672 camera is good for 9.73x6.48 inches at 720 PPI so anything smaller than about 9.7x6.5 inches and it'll downsample.  Bigger than 9.7x6.5 inches and it'll upsample to 720.


You are overcomplicating things by trying to make some association between 'DPI" and "PPI".  A "dot" is not a "pixel".  Just because your printer can spit 5760x1440 "dots" on a page doesn't mean you can equate each one of those dots to a pixel.  A dot can only be one of a few primary colors: to get a full color equivalent of a "pixel", you'd have to mix multiple "dots" together to get every color you can reproduce in a "pixel".

So Epson would never try to claim that their printer can reproduce an image at 5760x1440: they use a lower multiple (usually 720) and their drivers run at that PPI.  By the time the printer mixes 16 dots (8x2) made up of colors like cyan, yellow, magenta, red, green, blue, black, and gray, you can get a reasonable faximile of about 720 PPI of "image".  Similar with Canon: they wouldn't claim Canon printers that run at 4800x2400 can print an "image" at that resolution.  By the time you muddle together all the "dots" you need to get a full color image, we'll say you have about 600 PPI worth of "information" available on the page.

BTW, your camera even does something similar since among your 7008x4672 pixel image, your camera only captures one color (red, green, OR blue) for each of those pixels.  So it is only capturing 1/3 of the color information and the other 2/3 is "guessed" based on neighboring locations.  So you can get pretty complicated (convoluted) trying to define what an actual "dot" or "pixel" really is.  The bottom line is that most Epson drivers run at 720 PPI and most Canon drivers run at 600 PPI.  DPI is just a sales figure to tell you the absolute limit of the hardware (printhead, drive, etc.).  If you like cars, DPI is more akin to horsepower and PPI is like 1/4 mile time since DPI is the output of the "engine" and PPI is more like what results end up on the paper.

Mike