Working file resolution for current Epson printers
I had a business meeting with Epson imaging scientists. One of them is the top project leader for all print heads for professional and consumer photo printers. According to them, current native Epson printer’s heads are either 300 dpi or 360 dpi. So long as you are using EPSOM DRIVERS to print your images, your working resolutions should be multiples of these nozzle numbers to have maximum results. So first find your native resolutions of your print head of your printer then work from there. If you can afford, 720 dpi files or 600 dpi (or 1440, 2880 / 1500, 3000 dpi) as higher dpi should create better results if you can afford, though human eyes might not distinguish them comparing to lower res. Most practically, 300 dpi or 360 dpi (or 150 dpi or 180 dpi) should be good. However, if you use 3rd party professional RIP's, things are different. You have to use different algorism that I posted in past here, which I could not find it yet….
So I apologize my prior comments for this matters..., which was only referred to 3rd party RIP's.
#1. "RE: Working file resolution for current Epson printers" | In response to Reply # 0esantos Nikonian since 10th Nov 2002Sat 26-Jan-13 12:51 AM | edited Sat 26-Jan-13 12:31 PM by esantos
Epson printer’s heads are either 300 dpi or 360 dpi
So which printers use which print heads? Since this is not usually published information how do we determine the native resolution of, say, a R3000?
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#2. "RE: Working file resolution for current Epson printers" | In response to Reply # 1
#3. "RE: Working file resolution for current Epson printers" | In response to Reply # 0
I'm surprised that the Epson engineers would make a statement expressing the printer resolution as DPI for its my understanding that the proper metric would be expressed as line frequency or more commonly line screen.
But none the less, I think you are confusing two different concepts. Inkjet printers produce dots, image files contain pixels. The only time an inkjet dot directly equates to an image pixel is when producing line art in one of the native ink colors. Once you stray from the ink set colors, then printer resolution must be reduced to simulate a wider color gamut.
So assuming you meant image PPI resolution not printer DPI resolution with much of this discussion, then going above 600 PPI will only bog down the printer driver or RIP's algorithm and unnecessarily lengthen printing times without any appreciable gain in printed image quality even under close scrutiny.
At least that is my present understanding.
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#5. "RE: Working file resolution for current Epson printers" | In response to Reply # 0
I have chased this dragon before, getting close but always one step away. It eluded me and scurried away and I was content that I at least got near enough. But you have awakened that dragon once again so I must give chase once more!!
>I had a business meeting with Epson imaging scientists. One
>of them is the top project leader for all print heads for
>professional and consumer photo printers. According to them,
>current native Epson printer’s heads are either 300 dpi or 360
>dpi. So long as you are using EPSOM DRIVERS to print your
>images, your working resolutions should be multiples of these
>nozzle numbers to have maximum results.
Well you would expect a project leader for all print heads to know what he is talking about, so who am I to question! But I must for this just doesn't make sense.
If you look at the specs for the Professional printers you find many heads with 360 nozzles per channel and some with 720. The lower end Photo Printers seem to have 180 nozzles per channel. So while the Epson Engineers stated 360 DPI seems possible (although I have my doubts), where does the 300 DPI fit in? Also how does the 180 fit in?
It's my current understanding that the number of nozzles goes to print speed not resolution. After all just think for a moment, what would be the minimum amount of nozzles needed per channel for a printer to function? I would think one nozzle would suffice. What would be the down side to only one nozzle per channel; excessively long printing times. But while the number of nozzles aids print speeds, the spacing of the nozzles I would think need to coincide with the printer maximum resolution.
What would be the optimal image resolution PPI to send to a printer? Well some believe it is a subset of the printer DPI resolution. A inkjet can only either print a dot or not. It cannot almost print a dot or half dot. Also to simulate a wider gamut than the ink set it needs to use more than one dot to simulate a color. With today's stochastic dithers it is quite a complex layout so it's hard to say exactly how many dots are needed to archive full gamut. Some time ago Rags Gardner did an excellent article on his musings on finding an optimal resolution for his R2200 and he determined 288 PPI was the sweet spot necessitating 5 ink dots. So for arguments sake lets assume that Epson printers maximum resolution is 1440 when constrained to the ink set. If we go beyond the ink set and then need 2 dots or 3 or 4 or,,, ;you would end up with an image PPI progression of 720, 480, 360, 288, 240, 205.7, 180,,,(I'll stop here for it's my experience any PPI lower is sub standard quality). But again the question really is how many dots are required to reach optimal color gamut?
Some time ago when I was researching this and printing tests I discovered serval things. At the time I was using files from a D80 so was limited to about 322 PPI on an 8.5x11 print. I only used resolutions that were evenly divisible for my HP Photosmart 8250 with its maximum 1200 DPI which were 300, 240, 150 and 120 PPI. What I discovered was somewhat surprising in that the one I picked as providing the best quality was highly dependent upon viewing conditions. Under all conditions I was always able to pick the 120 PPI as the lowest quality. But on the dinning room table about 3feet from the lighting fixture which had a 100watt frosted incandescent inside a white plastic globe I regularly picked the 150 PPI as best quality with the 240 and 300 PPI a close second and third. But outside in open shade I regularly picked the 240 PPI as best with the 150 and 300 PPI a close second and third. But in direct sunlight I could then easily pick out the 300 PPI as best. Oh and by the way the print head had a 650 nozzles per channel with 6 channels for a total of 3900 nozzles which doesn't seem to match with the 1200x4800 DPI specification.
Now that I have a D7000 to provide more PPI resolution and a Epson R3000 I would like to repeat that test sometime.
I also when researching how many dots it took to simulate full gamut I came up with the hair brained idea that I would print individual pixels of various colors then count the dots. Well 1200x4800 DPI puts down some really small dots so that idea was a bust. But I did learn something from it. At 150 to 200 PPI a pixel sort of looked like an overstuffed cardboard box. At 120 PPI the box started to become squarish. At below 120 it was obviously square looking. To me that seemed why 150 PPI is the breaking point for printing and close viewing. At 150 PPI and the overstuffed box you don't notice the pixelated affect. Once the dot grouping becomes squarish, the image quality takes a hit.
So if you ever have the chance to meet with these engineers again, i'd ask them about the line screen and nozzle spacing specification. And I'd also ask exactly how many dots does the stochastic dither need to create the full gamut capability. Then well have a better idea of what the ultimate resolution might be.
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#6. "RE: Working file resolution for current Epson printers" | In response to Reply # 0
Again I presented wrong information regarding 300 and 360 dpi, which are utilized in Epson Industrial printing machines including labeling and textiles.
As reply from Epson, most of the native print heads resolutions for Epson consumer printers are 180 dpi including R3000, 4880, 4900,etc.
#7. "RE: Working file resolution for current Epson printers" | In response to Reply # 6mikeguil Registered since 18th Dec 2005Wed 30-Jan-13 12:22 AM
My understanding is that Epson uses the 360ppi model and Canon printers use 300, so resolution should be in multiples of those figures for the respective printers.
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#8. "RE: Working file resolution for current Epson printers" | In response to Reply # 0
I searched for additional information and found in the Nikonians Reference Library an Epson White Paper, "White Paper on Print Quality Issues and How to Cure ". On page 19 under the heading, How to Avoid "Jaggies", it clearly states that Epson print heads have a native resolution of 360 dpi.
Immediately following this section is one on what resolution to send to the printer, indicating that all output resolutions from Epson printers are direct multiples or half of 360 dpi.
Hope this helps.
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#9. "RE: Working file resolution for current Epson printers" | In response to Reply # 8elcee Nikonian since 01st Nov 2005Wed 30-Jan-13 04:22 PM
One thing I do not like about Michael Reichmann's website is that he doesn't date his articles.
This article may be germane to this conversation, even though the most-advanced Epson printer he mentions is the 2000P --
#10. "RE: Working file resolution for current Epson printers" | In response to Reply # 0
First of all, I am sorry for posting incorrect information in this threads, especially at the beginning.
However, now I got the right information in which Epson drivers work with the algorism that use multiple of 180. The optimal file resolutions will be numbers that are multiple of 180.
This is what I gathered from Epson.