4 Replies Latest reply on Mar 15, 2011 7:00 AM by Lucca man

    Upscaling and noise reduction in ACR

    Mollysnoot Level 3

      I've been thinking about upscaling images and the best time to do so (if I need to of course) in my workflow. As I understand it, it's always best to carry out any noise reduction prior to upsampling an image, as this helps avoid increasing the size of any noise that may be apparent in the image.


      However, I'm thinking that in ACR, this in theory would not be neccessary as ACR would carry out any noise reduction and upsampling in a pre-defined processing order. So put simply, I could increase the image size and then carry out any NR as required after upscaling. This would allow me to tailor the NR to fit the increased image dimensions (and of course I could then carry out capture sharpening for the larger image as well).


      Is my thinking correct here - does it not really matter in terms of image quality if I don't do any NR before changing the image dimensions in ACR?



        • 1. Re: Upscaling and noise reduction in ACR
          Yammer Level 4

          I would have thought so.


          As ACR is doing the demosaicing itself, upsampling should actually be a modification to this process. My logic is that, as it has to interpolate anyway, it just has to interpolate some more!

          • 2. Re: Upscaling and noise reduction in ACR
            Noel Carboni Level 8

            I did a lot of experimentation with upsampling during conversion.


            I found that - in my opinion - upsampling during Camera Raw operation yields superior results to doing it later.  I also believe that dialing in some noise reduction during Camera Raw is needed, as even low ISO images get pretty grainy otherwise.


            Every camera is different, but what I ended up saving for defaults is this, keeping in mind that I do my conversions to the largest possible image size, then downsample later for specific uses.




            Only you know what your goals are and what you like in your images, so I encourage you to experiment as I did with different combinations of settings to try to find the right balance.



            • 3. Re: Upscaling and noise reduction in ACR
              Mollysnoot Level 3

              Thanks to you both for your answers.


              That confirms that my thinking on this is correct then. And I agree Noel that even a low ISO image would probably need some NR applied if it's going to be upscaled to any significant amount.



              • 4. Re: Upscaling and noise reduction in ACR
                Lucca man

                I did also a lot of testi

                ng about upscaling in ACR of after conversion in Tiff and I came at the

                same conclusion: in my opinion it is better upscaling with ACR.


                Related to sharpening and noise reduction, I did NOT find any standard set of values, but different values according to the different types of images, but always, in my opinion, a bit of noise reduction is needed.


                Best regards

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