[RioRico]

Before digital cinematography, standard cine was shot on film of less than a half-frame, close to APS-C size. [History: What's now FF, 36x24mm, used to be called double-frame.] The lenses used had nowhere near the resolution of our DAs. The filmstock was often cheap and low-res except for fancy Technicolor blockbusters. And these frames were projected onto screens about 10x15m / 30x45ft, say at 80x+ enlargement.

How was that possible? 1) Motion obscures optical defects. 2) Nobody looked too close. (Kids up in the front row weren't watching the screen anyway.) The lesson? Anything looks good if you're far-enough away from it. I've printed 810x1215 pixel shots at 30x45cm / 12x18in and larger. Glassed, framed, and hung high, they look artistic if not purely photographic.

If you want 5m-long prints that withstand pixel-peeping, use a 645D. For more modest results, just remember that presentation trumps everything.

[slip]

My wife made some 12x12's for scrapbooking with her k100 and kit lens without any resolution problems. also printed a couple of 16x20 on both the k100 and my k10 with sigma 17-70 with great results

cheers

[patrickrea]

Quite often I have printed 16x20 images from my 6mp *istDL and all have worked out fantastic. I have one of the images hanging in my restaurant and when people tell me they 'have' to get a new camera to make bigger images I point to the photo on the wall. That's how I sold my *istDL in less than an hour to one of my staff. I don't have a printer that big so I have been using the UPS Store in Etobicoke on the Queensway. They have a guy by the name of Jared doing the printing who actually cares about what he does.

I printed one of my wedding photos (shot on a Nikon but who cares as we are talking about image size). The image was a 10MB tiff that I resized and cropped in Elements 8 to creat a faux panoramic image at 30" x 58" and 100dpi. After the resize using Digikam, the image was a whopping 90MB in size. I had my signage company print it on their monster Epson Stylus 7900 using "Digital Suede". The final image looks fantastic and even my VERY picky wife is happy. You can even see the glimmer of our wedding bands.

[dominikkolendo]

just thought i'd add:
i printed a 4x3 foot print from a kx 12mp image.
i opened the RAW and exported it as a 4x3ft@300dpi file, then opened in gimp and edited some levels and sharpened a bit.
(this was about a 300 GIGABYTE file btw, so every filter took about 20 seconds to apply)
from anymore than 2 feet away it looks like it was taken with a giant sensor, if you get close you can see the degraded image quality, but, if you print at 4x3 you dont exactly need the image to look good with someones face pressed up to it.

[Alizarine]

I was about to quote RioRico from somewhere when I saw his post above.

Well, yeah... though I haven't tried yet (printing beyond max suggested size), the bigger you print, the farther you should be to view it "nicely".

[demp10]

just thought i'd add:
i printed a 4x3 foot print from a kx 12mp image.
i opened the RAW and exported it as a 4x3ft@300dpi file, then opened in gimp and edited some levels and sharpened a bit.
(this was about a 300 GIGABYTE file btw, so every filter took about 20 seconds to apply)
from anymore than 2 feet away it looks like it was taken with a giant sensor, if you get close you can see the degraded image quality, but, if you print at 4x3 you dont exactly need the image to look good with someones face pressed up to it.

I am sure you meant Megabytes. A 4x3 ft image at 300dpi is 14,400 x 10,800 pixels for a total of 156 MPixels times whatever bit depth you were using.

A 12 Mpixel image, if well focused, will give great 4x3 ft prints but the choice of the re-sampling algorithm will dramatically affect the final quality. Most image processing software usually offer bi-cubic convolution as the highest level of re-sampling quality which is fine maybe for a 2X enlargement. You can get far superior results using a RIP (Raster Image Processor) engine to do the re-sampling on the fly before printing; just provide the original image and specify the output print size. A RIP engine can be expensive but if you print at large sizes often, it is a very good option.Alternatively you can use a print shop with such a setup.

BTW it is not necessary to re sample the image at that high (300) dpi. Anything in the 150-200 range is more that enough, and for large prints that typically will be viewed from a greater distance you can go much lower with good results. It is best to use an integer multiplier of the printer's actual resolution. For Epson printers this will be 90 dpi or180dpi so the printer firmware does not have to deal with fractional values during dithering. A RIP engine will do that for you on the fly so there in no need to make a special sized file for the print.

[dominikkolendo]

yes, you are right i meant megabytes, i just typed that without realizing it, good catch.
lossless TIFF file 8-bit CMYK.
upscaled sinc NOT bicubic.
the print shop said they'd prefer 300dpi, and i always print at a resolution native to the printer.
you are right that 300dpi is only necessary for text/fine detail, if the printer actually prints at that reslution, but for this particular print, i used 300 dpi and it was superb.

[rawr]

Imaging Resource say the K-x prints great up to 20x30 inch prints:

The Pentax K-x's printed output is really impressive, able to output usable 20 x 30-inch prints at ISO 100, straight from the camera with standard noise suppression on. They're slightly soft in some places, tack sharp in others; a little sharpening in a program like Photoshop could make them even better. 16 x 20 images are about the same, with a little more sharpness than the 20 x 30-inch prints. The amazing part is that print quality remains this good up to ISO 800! Even our troublesome red swatch still looks better than most cameras do at ISO 800, even when printed at 16 x 20.

[demp10]

Imaging Resource say the K-x prints great up to 20x30 inch prints:

Such a statement is meaningless without specifying a viewing distance for the print.

From their description "examining them closely" I would assume that they print them and then look at them from reading distances (if not closer). This may be fine for 4x6 snapshots, but in the real world one prints photos big to frame them and hang them on the wall. A certain distance (depending on the size) is needed to truly appreciate the entire image (and not the printed dots).

Examining closely a large print has only academic value and for the most part it will reveal the quality of the printer/inks/paper/driver/RIP engine used and not the source image. If the same image is printed on different printers/inks/paper/RIP engine, it will look dramatically different.

Billboards are routinely printed at resolutions as low as 10 dpi and they look great from 100+ feet on the street.