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PHOTOSHOP
TIP: Enlarging Digital Camera Files
My Canon 10D, a 6.3 megapixel camera, produces images that are 3072 x 2048 pixels, which means that I can make a 10 x 15 inch print at 200 dpi. 200 dpi is the minimum resolution I use for continuous-tone printers like the Lightjet or the Chromira. For most inkjet printers, like the Epson 9600 that I use, you can set any resolution you want, but below a certain point the image starts to look fuzzy and show individual pixels, especially along diagonal lines. Where is that point? That's a subjective matter, but for me it falls somewhere between 150 and 200 dpi. At 200 dpi, the image looks clean and sharp. At 150 dpi, it starts to fall apart. So, for the purposes of this tip, I'll use 200 dpi as the minimum resolution necessary for printing. For me to make prints larger than 10 x 15 from my 10D, yet still keep the resolution at 200 dpi, I have to create more pixels. Rather, I have to let Photoshop or some other program create more pixels. There are a lot of ways to do this. Some work better than others, but no program can invent detail that the camera didn't capture. The best you can hope for is to preserve as much information as possible. I'll examine four different methods of enlarging digital camera files, and then show you samples of each so you can make up your own mind about which works best. But first I want to put in a good word (a plug?) for Adobe's RAW plug-in. Adobe
RAW Plug-in If you work with RAW files, this plug-in alone is worth the price of the upgrade to Photoshop CS. It makes working with RAW files much easier, and has a host of great features. For example, it has some excellent noise reduction tools, and tools for reducing chromatic aberration (color fringing). It has a color temperature slider that makes warming filters obsolete. But best of all, and most relevant to this discussion, it improves image quality. I'm not sure how, but it does. Here's a comparison from the image above. The files have not been enlarged or resampled, but one was processed using the Canon software that came with my camera, the other with Adobe's RAW plug-in (neither has been sharpened):
No, I don't
get paid by Adobe! But they do get it right sometimes. Note that I haven't
compared the RAW plug-in with Nikon's software, or Fuji's, or anyone else's
-- just Canon's. Perhaps the other manufacturer's software is better.
Let's hope so! Enlarging
a Digital File Photoshop's
Bicubic Interpolation The Stairstep
Method Using
the RAW Plug-In Genuine
Fractals Comparing
these methods
Results: While Geniune Fractals produces sharper edges than the other methods, and makes prints that appear sharper overall, sometimes that comes at the expense of other, subtler details. What should be smooth transitions can become abrupt edges, resulting in a strange, "digital" look. I've created two other samples below. Note how in the first sample you can actually see less detail in the veins of the aspen leaf in the Genuine Fractals version, while in the second sample the RAW plug-in creates a smoother transition from the light to the shaded side of the branch.
There is no perfect solution. With the best enlargement methods, I think my Canon 10D images are comparable to images captured with fine-grained 35mm film, but they don't hold up to medium format film. The biggest difference I found in these tests was not in the various enlarging methods, but between processing RAW files with the Adobe RAW plug-in versus Canon's software. The RAW plug-in is a big improvement and a pleasant surprise. Michael
Frye is a professional photographer based in Yosemite National Park. His
articles and images have appeared in Outdoor Photographer, American Photo,
and in many books, calendars and posters. Click
to visit his website. Leaf Text and photos ©2004 Michael Frye, All Rights Reserved. This page may not be reproduced without the permission of the copyright holder. |
The
problem with most digital cameras is that they simply don't capture enough
information to make large prints. Smaller prints, up to 8 x 10 inches,
are no problem for most newer models -- at least those that capture 4
megapixels or more. But larger prints, 16 x 20 and up, are still problematic.
