3 Replies Latest reply on Nov 10, 2012 7:33 PM by NY2LA

    8x8 Blocking Artifact After Compressing Gaussian Blurred Images

    NY2LA Level 1

      I've been experimenting with using Gaussian Blur on uncompressed TIFF images. The TIFF images consist of scans of printed images with a screen ruling.

       

      I've been noticing an 8x8 blocking artifact when compressing the blurred images to JPEG's. (The reason for not using the scanner's Descreen feature is so that I can selectively blur.)

       

      Here, a JPEG without prior blurring appears on top, and a JPEG with prior blurring appears on the bottom:

       

      Screen shot 2012-10-31 at 3.28.14 PM.png

       

      Screen shot 2012-10-31 at 3.29.03 PM.png

       

      Has anyone encountered this artifact, and found a way to avoid it? Would blurring the JPEG, instead of blurring the TIFF beforehand, be preferable?