I've bought an Epson L8180. How do I find the real DPI of the printer? The data sheet states "5760x1440dpi" but surely that can't be right.
>>4312355Take macro photo of a print.
>>4312357What will that accomplish if I don't print some specific test chart?
I don't know for sure but just making some assumptions. First off I'm assuming the DPI is different in each direction due to the method used i.e. in one axis it's moving the print head, in the other it's moving the paper. Only the lowest resolution is what really matters so that's 1440 DPI. Because there's 3 colours if we divide that by 3 we get 480 coloured pixels per inch which seems like a reasonable number.
>>4312355All EPSON printers operate at 1440 DPI. This is 5760 dots for the CMYK, and 1440 steps vertically per inch with the stepper motors.Some models do 2880 but that's just finer stepper motors, the 5760 is usually the same and this is divided by the colors (CMYK) so it's 5760/4=1440, you can at most do 1440 DPI in pure black. This is what comes out of the nozzles. 1440 DPI per color.
>>43123772/2To add to this, this literally means that yes if you have a vector image or logo you need to be aware.Also if you have images that exist at 300 PPI, you will need to interpolate them to fit 1440 DPI printing or let the printer handle that scaling.If you're looking for 1:1 input-output with a 300 DPI file you need to use HP/Canon/Brother who use 1200 DPI for their nozzles.EPSON is essentially fucking retarded and "special" here, with a hardware DPI value literally nobody has content designed for. This means if you're trying to print test targets and do macro shots, you will see nothing but problems.Paper bleed blurs prints a little and masks the issue but the fact is the image is already blurred before the print even begins when trying to print a 1800x1200 image for a 6x4 print on an EPSON because it's incapable of directly translating that to ink droplets without INTERPOLATING.
>>4312378So far I've tried some test prints on the 5"x7" Ultra Glossy Photo Paper and wasn't really happy with the result. Perhaps because I was sending the wrong resolution to the printer letting it do the interpolation instead of me.So when you say 1440 DPI that means for a 5"x7" photo I need to send a 7200x10080px image? Correct?
>>4312381Yes, exactly.When you send a 1500x2100 pixel image (300PPI 5x7) to a printer it will simply upscale it (by itself) to function at its actual hardware res. If you have more real pixels to feed it, do so. If not, consider just upscaling with nearest neighbor to match the machine's res to prevent it making mistakes or upsampling it in a way you don't like.On most brands 300 DPI files can be losslessly upsampled with nearest neighbor pixel doubling/quadrupling but if you have 300 DPI files those will always be somewhat lossy when printed on an EPSON.EPSONs are technically higher res but since they exist outside of the traditional values it's kind of not an ideal situation.Not all droplets will be pixel detail, paper bleed and droplet spread exist but feeding appropriate resolution files to prevent digital resampling in printer firmware can still be beneficial.For ultra quality just know there's a reason why people do paperwork with laser printers, they're sharper, and can do like 2400+ DPI for very crisp lettering. Inkjets are always not as sharp but they have smooth color gradations and the ability to produce nice looking photo prints. Not suitable for view under a microscope, but good in person.
>>4312385thanks anon
>See anything related about Printing>See everything is gravitating to 300 dpi or ppi Why 300 is the golden number in DPI? Why not 100 or 500 or 1000?
>>4312385>just know there's a reason why people do paperwork with laser printersSPEED
>>4312443>Why 300 is the golden number in DPIit is twice as much as 150, which in turn is the nice rounded number which is twice as much as 72, which is what resolution dot matrix printers had.
>>4312355>The data sheet states "5760x1440dpi" but surely that can't be right.The printer is capable of laying down dots at that resolution. That's how it's able to reproduce so many tones and colors with its ink set. Extremely fine halftoning.However, you may not actually be able to feed that resolution to the printer and expect to see it on paper. Obviously not with shades of gray and colors since you need multiple dots to simulate the tones and colors. Each pixel you feed the printer breaks down into a set of dots. But even with pure black and white line art, the printer driver probably scales input to 720x720 or 1440x1440 before figuring out the halftone.Years ago, when I got my 3880, I remember testing it to try and figure out what resolution could actually be sent to the printer using B&W line art. I seem to remember seeing improvement all the way to 1440 ppi. So on pure B&W, which means one ink, the printer was able to accept/render 1440 ppi. This requires special paper, i.e. your typical office paper has a dot bleed size larger than 1/1440.On color photographs there was no improvement beyond 720 ppi, even on sections that had a pure black line on a pure white background. Beyond that I found that- 180 ppi was acceptable for most shots.- 240 ppi saw a large improvement over 180 ppi.- There was some improvement to 360 ppi, but you really had to look for it.- On carefully crafted images you could see improvement to 720 ppi in monochromatic areas, suggesting photographs are scaled to 720 ppi before halftone. But otherwise there was nothing to see between 360 ppi and 720 ppi.- By that time the scaling algorithms in the printer driver were already so good that hitting a multiple of the printer's resolution didn't matter. 240, 235, 245, 252 ppi etc. all came out the same.
>>4312378>Also if you have images that exist at 300 PPI, you will need to interpolate them to fit 1440 DPI printing or let the printer handle that scaling.>If you're looking for 1:1 input-output with a 300 DPI file you need to use HP/Canon/Brother who use 1200 DPI for their nozzles.By the late 2000's the driver scaling was so good that this does not matter at all. You don't need to scale your 300 ppi image, and sending data at a multiple of the print head resolution or not makes no difference.The only reason to scale in PS is if you have a very low resolution image because you can take steps to try and smooth out jaggies. If you send 72 ppi to the printer it's going to faithfully reproduce it and you will be able to see the stair steps. But 300 vs. 360 vs something odd like 305 is irrelevant. If 300 ppi is what you've got, it's what you're going to see on a good photo paper.>when trying to print a 1800x1200 image for a 6x4 print on an EPSON because it's incapable of directly translating that to ink droplets without INTERPOLATING.None of these printers "directly" translate the pixels to ink droplets. All of them scale to something they want internally and then apply a halftone.
