RAW enlargement question

[imhotep]

Hello all,

I've been taking digital photos for a few years, but I'm relatively new to shooting in RAW. As I try to research this format and learn its pro's and con's, I find a lot of conflicting info. So, I'd like to ask a very specific question about RAW image processing.

I've heard that a RAW image can be enlarged (while still maintaining acceptable quality) to larger sizes than a compressed image can. This has sparked most of my interest in RAW, as I would like to be able to enlarge my landscapes to 30x40 or so.

My question is, in what order is this process accomplished? For example, does the user need to convert the RAW file to TIFF first, and then make the enlargement, or can a RAW file be enlarged and then converted?

My thanks for any knowledge you are willing to share.

[jfrancho]

You can change the image size in ACR (Adobe Camera Raw) before conversion. You can also do it later in the workflow, after converting to a 16 bit/channel format (.tif or .psd). There are several methods for upsizing. There Photoshop plugins, like Genuine Fractals. GF is expensive. There are other alternatives along with other methods, like Edit > Image Size..., listed here: http://photography-on-the.net/forum/showthread.php?t=178175.

[Curtis N]

Raw Shooter Premium and DPP also give you the option to resize on conversion (not sure if Raw Shooter Essentials does), though I haven't tried upsizing with it, and don't know what sort of algorithm is used.

I have doubts that resizing with a RAW converter would do a better job than resizing a TIFF file after conversion. You only have so many pixels.

[jfrancho]

Forgot to add this: Generally speaking, I try a bunch of different methods, and compare the results, after final output sharpening at 50% zoom, and pick the best looking version. It seems that the best upsample method is best determined on a per image basis.

[imhotep]

Many thanks, that helps.