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Tuesday, November 29, 2011

The Right Resolution

The conventional wisdom says set 300 dpi and forget it, but it turns out that there’s more to optimizing image resolution for fine-art printing

This Article Features Photo Zoom

Figure 17 Output sharpening using PhotoKit Sharpener 2 by PixelGenius.

So, does this hold true for the consumer, professional and commercial versions of inkjet printers? Yes, for the recommendation to upsample to 360/300 dpi. I'm not sure the same argument can be made for upsampling to the higher 720/600 ppi case. I've not printed on any Canon consumer photo printers, although I have printed to an Epson R3000 printer and I've been able to detect some benefit to upsampling to 720 ppi. But since that printer doesn't have the same Finest Detail option, the differences are more akin to the differences seen in upsampling to 600 ppi on the Canon prints.

How does the paper you print on impact the results? Well, I specifically chose glossy paper for the purpose of scanning. My normal paper is Epson Exhibition Fiber Paper or Luster. Both papers can hold the Finest Detail settings when printing to Epson, and I presume (although I didn't test this) that similar papers would show some benefit when printing on Canon. How about matte or watercolor papers? Not so much. I'd still suggest upsampling to the base-level resolution of 360/300 dpi, but the paper's ability to hold detail at the higher resolutions of 720/600 dpi is doubtful. Personally, I've not seen the higher resolution provide much, if any, benefit.

Does print size have any impact on the output resolution? Yes, as indicated before, you need more resolution when printing small and less when printing big. Aside from the whole "photographer's nose" issue, for even the largest prints, I'd still suggest upsampling to the base-level 360/300 ppi resolutions.

Not Printing From Lightroom?
What if you don't print from Lightroom? Well, first off, I suggest you think about doing so for the reasons mentioned in the article—as well as for the improved printing workflow. Rather than have to spawn off multiple file iterations for printing various image sizes and resolutions, you can print directly from your raw file or a rendered and retouched TIFF file from within Lightroom.

If you print from Photoshop, you'll need to do some additional steps to take advantage of upsampled printing. You'll need to use the Image Size command to upsample your image to the desired output resolution.

Of course, you'll need to do your own flavor of output sharpening after the upsampling. Photoshop hasn't seen fit to add output sharpening to the Photoshop Print command. My biased suggestion would be to use PhotoKit Sharpener 2 to do your final output sharpening for print (Fig. 17).

If you're using a third-party print application, then you won't really be able to take advantage of the benefits of the upsampling beyond the base-level output resolutions. For example, the ImagePrint RIP from ColorByte Software is locked into the base-level resolution of 360 ppi for Epson printers (I'm not sure about Canon printer support). There's a third-party printing software called Qimage that can take advantage of the higher reported resolutions of Epson and Canon printers.