Luminous Landscape Forum
Site & Board Matters => Luminous Landscape Video => Topic started by: mminegis on August 04, 2007, 07:24:20 pm
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Hello,
I know I should read Bruce's book (which arrived yesterday) to understand all of what is bothering me on sharpening - in general and especially for printing - but I'd need a quick suggestion.
In CtoP when they talk about up-sampling and native resolution: If instead, I have as native resolution about 460 ppi to print in 8.5 x 11, I really need down-sampling (with Bicubic), as my R2400 would not print over 360 ppi. Also, to do output sharpening with Photo kit sharpener, there is nothing in between 360 ppi and 480 ppi. So instead of keeping native resolution (in this case 460 ppi) and run 360 ppi sharpening, I downsample first to 360 ppi and run the sharpening.
Is this the right approach? (even though I don't like throwing pixels away )
Thank you for your help!
Mari
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You're confusing image resolution and printer resolution. Ignore any printer resolution specs. They're meaningless.
If at the size you wish to print the image file is between 180 ppi and 480 ppi, leave it alone. If it's lower then 180ppi res up to about 300, and if it's above 480 ppi res down to about 360. The printer driver will choke on files over 480, and doesn't do as good a job of upressing as does Photoshop bi-cubic below 180.
This is as discussed in the tutorial.
Michael
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Thank you for your clarification. It's good to know that I can keep every pixel I've got!
On my image at 460 ppi native, should I run 360 ppi or 480 ppi output/inkjet sharpening (as there's none in between with photokit sharpener)?
mari
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On my image at 460 ppi native, should I run 360 ppi or 480 ppi output/inkjet sharpening (as there's none in between with photokit sharpener)?
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Generally, you pick the closest match, which in this case would be 480PPI.
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OK. I was running 360 so now I'll try 480 and see the difference (if I see it!) on paper.
Thank you for your reply.
mari
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OK, I see I'm getting to this topic a little late (better late than never, right?), but having watched Camera to Print last night, specifically, Chapter 12: Resolution....
At 00:01:04 we see a 1Ds image with dimensions of 16.933 in x 11.267 in @ 240 ppi....
At 00:03:41 Jeff opens up an uprezzed image with dimensions of 33 in x 21.957 in @ 246.303 ppi...
While the first image is at native resolution and the second is at interpolated resolution, both fall within Resolution's Sweet Spots of 180-480.
So what happens, say, if you wanted to print that first image as an 11 x 17? Using the same 1Ds file as an example, do I change the width to 17 (making sure resample image is unchecked), resulting in a height of 11.311 @ 239.059 ppi, thus maintaining native output resolution, or do I uprez to 17 @ 240ppi, opting instead for interpolated resolution?
I am printing to an Epson 7800 and in some cases a 9800. I thought the Epsons preferred a file that was at one of the "magic" numbers of 180, 240, 288, 360, or 480? If so, wouldn't that make the point of native resolution moot, since you'd end up having to up/down rez to get files to one of 5 magic numbers?
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These Epson printers rasterize image data at 360 PPI, but if you sharpen and print for whatever native resolution between 240 and 480 results from the image dimensions you chose, the printer driver resamples the data and print quality should be fine. I've tried alternatively resampling to 360 in Photoshop, or just letting the native resolution vary according to image width in the range of 240~480 and frankly you have to look close-up very, very hard to see any real difference between these options. When I do the latter, I Output Sharpen at the closest value PK Outputr Sharpener lists relative to the image PPI, going lower for a marginally less sharp result and higher for a marginally sharper result.
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So what happens, say, if you wanted to print that first image as an 11 x 17? Using the same 1Ds file as an example, do I change the width to 17 (making sure resample image is unchecked), resulting in a height of 11.311 @ 239.059 ppi, thus maintaining native output resolution, or do I uprez to 17 @ 240ppi, opting instead for interpolated resolution?
resize without interpolation. if the result resolution is within the acceptable range, leave it be and print as is.