I went to the NAPP Photoshop World conference in San Diego. (Briefest summary, it was worth the expense, but I won't go again).
Anyway, I took a class there where the instructor said that for optimal printing to an inkjet you should send a file with a ppi that equals 1/3 the dpi of the printer; ie. for an Epson with 1440 dpi capability you should send a file with a resolution of 480 ppi.
Now, I had always heard that no inkjet printer had a real output of more than about 300 ppi (I've heard 240, 320 and 360 ppi for various Epson printers). The 1440 dpi number is for the spacing of the component single color dots that make up a "pixel" of continuous tone color. In a short discussion after class the instructor confirmed he meant that to apply to all inkjet printers, though he allowed it didn't seem to be true for older inkjets.
Well, I felt I needed to test that. The best way I could think of to isolate the printer resolution was to create a digital file at different resolutions and print them. What I made was something that looks a bit like a UPC barcode. There are groups of five lines separated by a fixed number of pixels of space. All lines are 1 pixel wide, and the groups start with 1 pixel between the lines, and went up to 8 pixels between the lines. The pictures only show the first three groups.
I made sets of lines that ran both horizontally and vertically. This was done for 300, 400 and 500 ppi. I resized these by doubling the pixel resolution without resampling in Photoshop to get 600, 800 and 1000 ppi versions.
I used an Epson C80 printer and Epson Photo paper (the comment about older printer kinda leaves out my true photo printer; an EX). I printed in 1440 Photo (1440 x 720 dpi) mode.
Note, that the color was equal amounts of CMY, so multiple heads were involved, not just the black head.
I was surprised to see that, with a loupe, you can make out lines and spaces in the horizontal single pixel spaced lines up to 600 ppi. The vertical lines (remember Epson's dpi is 720 in this direction) could all be made out at 400 ppi, and in only one line was the space filled at 500 ppi.
In the horizontal lines, you can make out some lines even at 800 ppi. The other thing that surprised me was the variability of the single pixel lines at all resolutions. There seems to be rather a lot of variability in width.
Wow, this is getting way too long. What resolution files do you send to your printer? Do ppi s higher than 300 really make a difference?
Results:
Anyway, I took a class there where the instructor said that for optimal printing to an inkjet you should send a file with a ppi that equals 1/3 the dpi of the printer; ie. for an Epson with 1440 dpi capability you should send a file with a resolution of 480 ppi.
Now, I had always heard that no inkjet printer had a real output of more than about 300 ppi (I've heard 240, 320 and 360 ppi for various Epson printers). The 1440 dpi number is for the spacing of the component single color dots that make up a "pixel" of continuous tone color. In a short discussion after class the instructor confirmed he meant that to apply to all inkjet printers, though he allowed it didn't seem to be true for older inkjets.
Well, I felt I needed to test that. The best way I could think of to isolate the printer resolution was to create a digital file at different resolutions and print them. What I made was something that looks a bit like a UPC barcode. There are groups of five lines separated by a fixed number of pixels of space. All lines are 1 pixel wide, and the groups start with 1 pixel between the lines, and went up to 8 pixels between the lines. The pictures only show the first three groups.
I made sets of lines that ran both horizontally and vertically. This was done for 300, 400 and 500 ppi. I resized these by doubling the pixel resolution without resampling in Photoshop to get 600, 800 and 1000 ppi versions.
I used an Epson C80 printer and Epson Photo paper (the comment about older printer kinda leaves out my true photo printer; an EX). I printed in 1440 Photo (1440 x 720 dpi) mode.
Note, that the color was equal amounts of CMY, so multiple heads were involved, not just the black head.
I was surprised to see that, with a loupe, you can make out lines and spaces in the horizontal single pixel spaced lines up to 600 ppi. The vertical lines (remember Epson's dpi is 720 in this direction) could all be made out at 400 ppi, and in only one line was the space filled at 500 ppi.
In the horizontal lines, you can make out some lines even at 800 ppi. The other thing that surprised me was the variability of the single pixel lines at all resolutions. There seems to be rather a lot of variability in width.
Wow, this is getting way too long. What resolution files do you send to your printer? Do ppi s higher than 300 really make a difference?
Results:
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