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.acdc large file size?

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  • .acdc large file size?

    From my camera, RAW files download at about 20mb. If I use Develop in ACDSee to improve them, the file size stays much the same. But if I need to use Edit for some reason then they save as .acdc file format, and the size increases hugely, up to several hundred mb. This becomes a problem because I have synched to Google Drive and am running out of space.

    Although I know the solution is to keep my acdc format files elsewhere so they do not sync, what i am wondering is if there is a way to prevent ACDSee from inflating the size like this?

  • #2
    Developing raw files doesn't change their file size at all - they remain untouched. All edits are save as 'receipt' in a separate .XMP side car file. ACDC files are 'spiced' .TIFF files. You might save some space with switching to 'adobe deflate' in the options.

    ACDC files always(?) are 16 Bit TIFFs and with converting into 8 Bit TIFFs and using ZIP as compression method you could save 2/3 of the disk the space and also keep the spices (layers). E.G "convert.exe myinfile.acdc -depth 8 -compress ZIP myoutfile.acdc". Convert is part of imagemagick. This method is just an idea and not fully proofed!

    However you should always use 16 Bit TIFF for your intermediate image files. Everything else is lossy.
    Last edited by Emil; 11-20-2018, 05:00 AM.


    • #3
      Hi Lin_G,

      As Emil has pointed out, the ACDC file format is essentially a TIF with support for layers. One thing you can do to save space is to flatten the image. Flattening will allow you to save the image as the file format of your choice, potentially saving a lot of space. Keep in mind that once flattened, layers can't be modified or removed.

      For example, I took a 28MB CR2 and added an Exposure adjustment layer. The resulting ACDC file was 120MB uncompressed and 95MB with Adobe Deflate compression. By flattening, I achieved the following file sizes:
      TIF (uncompressed): 80MB
      TIF (Adobe Deflate): 47MB
      PNG: 31MB
      JPG: 6MB

      Every format naturally has its advantages and disadvantages, with the lossy JPG in particular being a poor choice for high-quality images, especially intermediate files.

      You can flatten the image from Layer > Flatten Image. The image will be flattened automatically if you save as a non-ACDC file format. Again, flattening will prevent further editing of the layers, so you may want to export an ACDC file to a folder outside of Google Drive's synced folders as a backup.

      Tristan H.
      ACD Systems


      • #4
        My goal was to save significant amount of file size, but keep the layers. Imho layers give the only right to exist for .ACDC files. With an option to save .ACDC files with layers as 8 bit files. lossless compression techniques like zip and deflate also work way better.

        But again, with converting 12 or 14 bit raw files into 8 bit files you always will lose data.
        Last edited by Emil; 11-21-2018, 05:26 AM.