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johns9744233
johns9744233
Participating Frequently
August 9, 2021
Question

Why are my TIFF files so large?

  • August 9, 2021
  • 2 replies
  • 7208 views

My raw images after conversion to DNG in Lightroom Classic (LRC) are approx 100mb. After editing in Photoshop (PS) and saving the TIFF file grows to 2gb, even after flattening the images. 

I have always used LRC but now ventured into PS but won't be able to continue this if the files are this size.

I suppose I have two questions for the forum. Firstly is this normal? Secondly is there another format I can try? I did try PSD but this is still 550mb?

Thanks

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2 replies

davescm
Community Expert
davescmCommunity Expert
Community Expert
August 9, 2021

Yes it is normal

The DNG format contains the raw image, which from a camera is normally 3 greyscale files one for red data, one for blue data and one for green data. The red channel carries data for one quarter of the pixels in the image, the blue one quarter and the green a half. Each pixel is normally 14 bits and the file is then compressed using lossless compression.

 

The TIFF file at 16 bit has two bytes for each colour channel at each pixel site. So 6 bytes for every pixel.  Unlike the raw (dng) file, Each channel red , green, blue has every pixel in the image. If you have more than one layer, then that increases the file size further. The file when saved may be compressed or not depending on your TIFF settings, but the files are always going to be larger than the raw files.

 

My advice would be don't worry about file sizes, increase your storage if necessary. That way you can focus on the best image quality. The one exception is when sending a file onward, in which case you may need to export a copy and use a lossless lossy compression format (such as jpeg) but that should never be used for master files.

 

Dave

 

 

    c.pfaffenbichler
    Community Expert
    c.pfaffenbichlerCommunity Expert
    Community Expert
    August 9, 2021
    That way you can focus on the best image quality. The one exception is when sending a file onward, in which case you may need to export a copy and use a lossless compression format (such as jpeg) but that should never be used for master files.

    Please forgive the nitpicking but you may have mistyped (»lossless« instead of »lossy«). 

     

    I also seem to dimly remember an issue where some compression would work less well (possibly to the point of increasing file-size) in 16bit – was it LZW maybe? 

    D Fosse
    Community Expert
    D FosseCommunity Expert
    Community Expert
    August 9, 2021

    That's right. LZW is for 8 bit data, and it can actually increase the size of 16 bit TIFFs.

     

    There's one more thing with compression: it can be computationally intensive and drastically increase open and save times. In many situations that's much more important than the resulting file sizes. As Dave says - don't worry about it, get more disks. Image files will be big and take up a lot of space, and sooner or later you will run out. Better to have a long term strategy for it, than trying to postpone the inevitable by compression.

      c.pfaffenbichler
      Community Expert
      c.pfaffenbichlerCommunity Expert
      Community Expert
      August 9, 2021

      What are the pixel dimensions of the tif? 

      8bit or 16bit? 

      Is there excessive Ancestors Metadata? 

      https://community.adobe.com/t5/photoshop-ecosystem/inflated-jpg-file-size-photoshop-document-ancestors-metadata/td-p/8055434

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