/////Working with Lightroom and Photoshop file size difference
Working with Lightroom and Photoshop file size difference2013-05-17T08:32:29+02:00

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Working with Lightroom and Photoshop file size difference

  • Author
  • Deneys
    Post count: 739

    Has anyone else noticed the huge difference in file size when working in Lightroom & Photoshop compared to Photoshop only.

    Photoshop only

    I open the Raw file (NEF D800) which opens first in Camera Raw 7.4. I do my basic changes, then click “open image”. It then opens in photoshop and asks to do a Colour space conversion. I convert it from Adobe RGB to working space Prophoto RGB. Once open I do a content-aware fill on a small aria (Bit of the soft box showing in photo) once done, I save the projects as a photoshop PSD file or Tiff.

    File size of PSD file is 99MB
    File size of TIFF file is 108MB

    Lightroom and Photoshop

    In lightroom I do my basic changes. I then right click on the photo and click on “edit in/Photoshop” it then opens in photoshop with out asking to do a colour space conversion (as LR is Prophoto RGB)
    I do the content-aware fill on the small aria and save the projects as a photoshop PSD file or Tiff.

    File size of PSD file is 216MB
    File size of TIFF file is 216MB

    Why the +- 100MB difference ?

  • Leo Theron
    Post count: 1582


    Adobe punishes you false singing and not doing that small change/change in LR… 😉

    OK…. I suspect that you have another layer that contains the change – the image is exactly double the size. This is an educated guess only.

  • Deneys
    Post count: 739

    one layer (done on main background layer ) and exact same process using LR & PS and PS alone :confused:

    except for the basic adjustments one done in LR and the other done in camera raw

  • Deneys
    Post count: 739

    Ok I tried to see what would happen if I did it on a separate layer and saved it like that…… now I know they say its only zero’s and one’s but the file size once saved is 723MB.

    Madness…. lets round that off to 1GB for a project that’s 128 projects and my terabyte is full.

    anyone………please help

  • Dave_
    Post count: 472

    I have noticed a similar thing. Tiff files are bigger than PSD, not 100% sure why though. But when going from LR to Photoshop, I have learn’t to always “flatten” the image before saving back to LR. Otherwise the file size is huge.

    The problem is worse when you edit in a plugin like Nik software, you just get a big tiff and no real way to reduce the size. Unless you edit in PS, use the plugin in PS, flatten the image and save back. However, the files are still huge (usually over 100MB).

    I am not sure there is a fix, as I have searched before. The usual “solution” is that “HDD’s are so cheap today, just buy more!”. Not really what we are looking for.

  • HeinrichR
    Post count: 630

    Suggestion, What is the file size when you set ACR to pro photo ( on the bottom of the window is a blue link in ACR if I remember correctly dont have PS with me) and export it from ACR as prophoto and not as Adobe, could it loose data because you use adobe from the raw file and then convert to prophoto is CS?, where LRoom uses prophoto from the beginning (I dont know the difference between a ADOBE and PRO photo ‘s file size )

  • Deneys
    Post count: 739

    Thanks guys. Wish I was at my PC right now.Will give it a bash tomorrow morning when I get home.

  • SteveG
    Post count: 616

    Putting out Adobe rather than ProPhoto from ACR will make no difference.

    What’s happening is that from ACR you opened an 8-bit image and from LR you exported a 16-bit image.

    8-bit gives you a file that’s 3x your MP count. 36×3= 108mb
    16-bit it’s 6x your MP count.

    The difference between the PSD and TIFF file sizes is down to lossless compression. The PSD probably has LZW or more likely ZIP compression in it while for the TIFF you have set no compression.

    Also: if your working space is ProPhoto then just tell ACR to go directly to ProPhoto and save yourself the conversion step. You’ll also reduce the chance that you’ll clip colours that are in your capture, but don’t fall within AdobeRGB. Not many real world colours that do this, but there are some.

  • Deneys
    Post count: 739

    Thanks Leo, Dave and Heinrich for your help.

    Steve you are correct LR exports it as a 16bit ProPhoto and PS converts it to a 8bit ProPhoto. If I do what Heinrich suggested and change the settings in ACR to 16bit ProPhoto both files are the same size.

    Just going to have to get some more HDD’s

    Thanks again to all

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