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Author Topic: V. basic Q re: resolution & printing.  (Read 2440 times)

KirbyKrieger

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V. basic Q re: resolution & printing.
« on: November 22, 2010, 09:01:20 pm »

Hi.  My shots are 4,000 x 6,000 pixels (Sony FF).  My printer recommends (iirc) 300 ppi for best quality prints (Epson 3880).  As I understand it, I can print any non-cropped images up to (4,000/300) 13.3" x (6,000/300) 20" and expect to get the best resolution my equipment can produce.

Is that correct?

I would like to eventually make some 30" x 40" prints.  How is that done?  I would like these to show well down to 12" viewing distance.  (At 12" my 13" x 19" prints look good.)  In order to maintain the same ppi, I would need a camera which records (30x300) 9,000 x (40x300) 12,000 pixels (108 MP).

That doesn't seem right (as well being parsecs beyond my reach).

Links are welcome -- I understand this is a well-trod ladder.  Thanks  :).

Graystar

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Re: V. basic Q re: resolution & printing.
« Reply #1 on: November 22, 2010, 10:59:54 pm »

The easiest answer...if you want great looking prints with the most detail then buy Qimage.

Slightly less easy answer...are you using Windows 7?  If so, then use the resizing function of your favorite software to crop and resize your image to 300 PPI.  Then use the Windows Photo Viewer to print.  WPV performs print sharpening, and will handle color space conversions.  The results are great.

The hard answer...you are stepping into an area that is poorly understood by many.  Getting the best resolution out of a printer is not straight-forward.   In order to get the most detail on paper, you need to apply print sharpening to your image.  Qimage does this, along with the correct resizing.  WPV applies print sharpening, but doesn’t resize.  There’s other software available that provides print sharpening functions, such as Nik Sharpener Pro, PhotoKit, LightRoom, and others.  But applying print sharpening by hand is tricky.  You can search Bing or Google for “output sharpening” and you’ll get lots of hits.  There are lots of techniques out there. 

Here’s an example of the same image printed first without and then with print sharpening...



The reason that images must be sharpened for printing is that printers don’t reproduce images the way a monitor does.  With a monitor each pixel is completely separated from one another, and each has a thin black outline.  When you print, one pixel is comprised of a matrix of dots.  The dots overlap each other both within the matrix and on the boundaries between matrices.  Because of this, images will lose detail and sharpness.  So output sharpening is used to restore what was lost.  It does so by tuning the image to the characteristics of the output device.

Output sharpening depends on the output device.  If I were to print an image on an Epson I'd resize to 720 PPI and make the image look excessively sharpened.  But if I were sending the image out to be printed, and I know the print shop uses a wet printer, then I would resize to the resolution of the wet printer and apply just a tiny amount of sharpening.  This is a very device-dependent process.
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NikoJorj

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Re: V. basic Q re: resolution & printing.
« Reply #2 on: November 23, 2010, 03:37:18 am »

I would like to eventually make some 30" x 40" prints.  How is that done?  I would like these to show well down to 12" viewing distance. 
With one of your captures, resolution will go down to ca 150-180ppi, which is not horrible at all with a good interpolation/sharpening processing.
QImage does it, Lightroom does it also, or you can do it yourself in PS : http://www.digitalphotopro.com/technique/software-technique/the-art-of-the-up-res.html

If you really want plenty of fine detail, you may also stitch 4 or 6 frames taken with a longer lens...
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Nicolas from Grenoble
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KirbyKrieger

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Re: V. basic Q re: resolution & printing.
« Reply #3 on: November 23, 2010, 07:08:16 pm »

Graystar and NikoJorj -- thanks for the informative responses.

Graystar -- I'm on a Mac.  I use Aperture and the Nik plug-ins, including Sharpener Pro (current versions of each).  I am in the process of learning how to use the Nik plug-ins.

NikoJorj -- That's very helpful, inc. the suggestion to stitch as needed, which of course I always forget as a possibility.  If 150 ppi can be made to work, that will give me 27" x 40" from my 4000 px x 6000 px images.  I suspect that will be large enough for my needs.  It's quite reassuring to know that with care I can go down to 180 or 150 ppi and still get excellent prints.

Thank you both.
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