Pixelation with 16x20s

[Bob Hall]

I have a 20D with 24-105L lens. A 16x20 print was noticably pixelated. I used minimal photoshop work, no sharpening minimal cropping. A friend shot a similar photo with his MII and it was much better. The question is: how much improvement would I expect with a 5D? The MII is just too expensive right now, and I don't really need all of its great features (but I have never used one). I print on an Epson pro 4000, premium luster.

[Walter_Kimmel]

It sounds to me as if you are not interpolating your image to get to the 16x20 size, and just changing the dimensions without "resampling." That would leave you with not enough pixels per inch to avoid the jaggies.

I use the 1D MkII, which gives me 8 megapixels of beautiful quality. However, even when I print at 13x19, I upsize my file using Resample with Bicubic Smoother, and depending on the printer, I keep the resolution at 300 or 360 pixels per inch. The lowest resolution I would ever use would be 240 ppi when printing with an Epson printer.

With appropriate output sharpening, I get stunning 13x19 prints, and on the Epson 4800, the 16x24's are impressive.

If you were to interpolate your image either with Photoshop's Image Size (as above) or an interpolation program such as Genuine Fractals, or print from QImage or a RIP that would upsize your file before printing, and compensate for both the digital capture process as well as doing proper output sharpening, you would get very satisfactory prints from the 20D.

That is, of course, that you used proper technique in the capture process. At 16x20, you are already cropping (throwing away) a good number of pixels! Why not print at 16x24? You will get the best results by:
1) Not cropping.
2) Using a tripod, mirror lockup and remote release or self timer to do away with camera movement, and high enough shutterspeed to neutralize inadvertent subject movement.
3) Depth of field preview to ensure that your DOF is as deep or shallow as you are hoping for.
4) Using the lowest ISO that you can at the chosen aperture and shutterspeed, to avoid loss of real detail from noise.

If these are all things that you are already doing, I apologize for implying that you're unaware of these issues. I make no assumptions about your level of expertise.

[ChrisPerry]

I got nice 16x20s with my 6mp 300D and my 20D and 30D do just as nice.

I don't use inkjet as output though, but a lab that does a continous tone print and they say to keep the DPI at 200 or better for best results (i've gone as low as 150 on 11x14 without a problem).

I just do a one-step resize with the bicubic smoother in PS. I've tried the bit of stepping it and up and don't like the results at all.

[DougAxford]

I regularly get great 20x24 portraits with my 10D. As posted, check your work flow

Doug

[David_Buzzard]

Just resize the images up to the size you want to print at. You can also decrease your resolution as you get larger. While an 8x10 looks great at 300dpi, you aren't looking as closely at a 16x20, so you can decrease the resolution down to 240dpi without too much trouble. Also remember to lay off any sharpening until you're at your output size.

David Buzzard

[NillToulme]

Or get Qimage and get spectacular results at any print size (or even combinations of different print sizes) without ever having to worry again about resizing, resampling or output sharpening.

Nill

[Bob Hall]

I use Qimage. I think I should have been more clear about what I saw. The skin tones look grainy, not pixelated (pixels looks like little rectangles). The appearance up close looks more "mottled" but with an 8X loupe it looks like film grain. (cropping was minimal).