1 Reply Latest reply on Dec 13, 2012 11:21 AM by web-weaver

    Reducing File Size in Photoshop




      I had a question on reducing the image size after editing in Photoshop. 


      After doing my changes in Lightroom, I typically make edits in Photoshop and then do some final touchups back in Lightroom.  The RAW file from my camera is approximately 24 MB.  After making my edits in PS, the TIFF file it produces (with all layers flattened) is in the 60 MB range.


      My question is, if before sending in back to LR, I change the image size in PS say to 12 MB or so, am I basically creating a lossy jpg file?  Meaning -- by reducing that TIFF file size down to 12 MB am I throwing out important information such that when I go back to LR I am losing information and won't have as much control as the 60MB TIFF file?


      I am trying to avoid having to keep upwards of 80MB per image (due to the RAW + edited file).  I don't want to lose imporant information so I will if I have to, but would prefer not.




        • 1. Re: Reducing File Size in Photoshop
          web-weaver Level 5

          If you reduce the file size in Photoshop you reduce the pixel dimension of the photo which means that you throw information away - independantly if you save as JPG or as TIFF or PSD.

          That means that the reduction in file size is a reduction in image quality.


          If you want to print the image you need a certain resolution (dpi) for the print - typically 300 dpi.

          If you want to make a print of let's say 8" x 10" at 300 dpi you need a pixel dimension of 2400 x 3000 pixels which results in a file size of roughly 22 MB (flattened file).

          If you have reduced your file to 12 MB you cannot make a print of 8 x 10 at 300 dpi without upsampling first, i.e. Photoshop (or Lr) have to "invent" the missing pixels.


          So reducing the file size is simply not an option - unless you use your images exclusively for the web where you don't need large file sizes.


          If you edit your Raw files in Photoshop you have to live with large file sizes.

          The only way to avoid that is: Do edit in Photoshop only if you absolutely cannot do it in Lr.