4 Replies Latest reply on Jun 27, 2008 5:47 AM by 01af

    Resolution In RAW

    Hudechrome-sd9sPI Level 2
      It was pointed out in the Photography Forum that using "Custom" with the crop tool allows one to pick the final size and resolution before going on to PS for final editing. Since the size/resolution chosen may require upsampling of the RAW image, this seems to indicate that it is better to do this in RAW than PS.

      Is there any validity to this?
        • 1. Re: Resolution In RAW
          michael shaffer Level 1
          In another thread, Jeff Schewe claimed there was very little difference gained from resampling in ACR. It was some time ago, but you can probably search for it within this forum -- keywords: Schewe, resolution (or variations on)

          edit: Sorry, but I couldn't find it ... perhaps Jeff will comment(?)
          • 2. Re: Resolution In RAW
            Mathias Vejerslev Level 2
            It is certainly a more convenient way of setting your final output size - you can still control everything in RAW, benefit from ACR sharpening and controls. I have read a few comparisons between ACR and Bicubic Smoother upressing, and Bicubic Smoother won by a hair, due to a bit harsher rendering of contrasty details in ACR (the interpolation mechanism in ACR is not exactly equal to any in Photoshop, AFAIK). But that was about the only difference. I do both, depending on the circumstance.
            • 3. Re: Resolution In RAW
              Hudechrome-sd9sPI Level 2
              I basically have no final output size. I set the image to my liking then depend on sizing whenever the need arises. However, when that arises, I have the option to sharpen in either space, so that's why the question.

              Thanks, Michael, Mathias.
              • 4. Re: Resolution In RAW
                01af Level 1
                Do not use Camera Raw's resizing feature! Or at least not for upsizing (maybe it's fine for downsizing; I don't know).

                When upsizing, Camera Raw (including the latest version which currently is 4.5 RC) will introduce ringing artifacts which are not there when doing the upsizing in Photoshop. Photoshop's resampling method Bicubic Smoother will give the same result basically as Camera Raw's resampling algorithm, just without the artifacts. So in Camera Raw, convert to the file's native size, apply some very gentle source or capture sharpening, and then do the upsizing in Photoshop using Bicubic Smoother.

                However those artifacts are very small; to notice them you'll have to look very carefully at very-high-contrast edges at high magnification (200 % or 400 %). At low-contrast or medium-contrast edges there won't be any visible artifacts. For practical intents and purposes they may be too small/too insignificant to pose any relevant problem---but why taking a risk? Subsequent sharpening tends to emphasize the artifacts.

                -- Olaf