Is there a noticable differance in print quality in sending a 150 dpi image or a 300 dpi image to this printer at a 20x24 print size. Assume that the image is shot with a digital slr camera 6 million pixels. I am being told by the lab that there is no differance in quality at normal viewing distance. The printer is set to print at 1440 ppi.
thanks
Like most things, it depends. It depends on the image - lots of detail, or lots of smooth area? Color or B&W? It depends on the driver - Epson, or a RIP? It depends on you, and your preferences. It depends on the lab, and their abilities.
The way it generally works is, the printer/RIP will upsize a lower resolution to a resolution that the printer is designed for. For example, if you send a 150 dpi (or 300 dpi) output to the Epson driver, it will automatically upsize the image to 360 dpi internally using whatever interpolation it uses, and print it that way. But that doesn't mean that the image has any more information in it, just that it has more pixels. You can't create more information from nothing....
So, whether you upsample the image in an image editor, or using a program like GF, or let the printer driver or RIP do it, you still have 6Mp of image capture. You are still spreading that 6 Mp of information across a 20x24 inch print. Your lab is probably right, you may not be able to tell the difference.
What I think you'll typically see in a print that large from 6 Mpixels is less sharpness than you might want; it will be somewhat fuzzy overall. Tonal relationships should carry through, and it will probably be pretty smooth.
In the end, all you can do is try it and see what you think.
Bruce Watson
Mike, all of the Epson Ultrachrome printers have a native resolution is 360 dpi. That means that if you send the printer a file sized at your desired output size at 360 dpi, the printer's driver will not have to interpolate the file; it can print it pixel-for-pixel. That is the way to get the best quality prints possible. Use the 1440 setting (there's no difference between that and 2880), and always feed it a 360 dpi file. If you compare prints made that way with prints made any other way, you will see a difference in quality.
~cj
Hi, this is my first post here, and the button instructed me to contribute an answer. I don't have an answer, so I'm contributing a question. Both Hogarth and Chris state that the Epson Ultrachrome printers upscale lower resolution files to 360 ppi. So the question that occurs to me is how good a job of interpolation does the printer's driver do? Maybe I'm better off doing my own interpolation using Photozoom Pro, which seems to do a very good job. Recently I had an old digital image I wanted to print large, and I upsampled from 117 ppi to either 180 or 240 (I'm too lazy to look for the file) before printing it on my Epson 7600. Would I have done better to go all the way to 360? Are you saying that if I had sent it to the printer at 117, the driver would have interpolated it up to 360 and it would have looked just as good as the 180/240 ppi file? Thanks for your help with this.
Robert,
Whenever you resize an image, whatever algorithm is used interpolates between pixels. Invariably, some information is lost. The only question is how much information is lost. You might well do better to resize the image outside of the driver and send the driver a 360 dpi file. You would have to test by making a print each way to be sure.
Bruce Watson
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