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MissM2
Known Participant
January 24, 2021
Question

Modify File Size, Keep Set Dimensions, Photoshop 22.1.1

  • January 24, 2021
  • 2 replies
  • 713 views

First, I apologize. I know there are numerous questions about file size in the support community for Photoshop, but I didn't read anything about locking file size and image/canvas size. I'm not super-technical, but I'm hoping I can learn how to do this as I'm starting a new art project where I'll need to be doing this regularly.

I just started using Photoshop again after a long break, and I'm using 22.1.1, the lastest update.  

Q: I need to supply a photo that is 13500px x13500px and the file size can't exceed 128mb. I looked all over the interface and tried modifications where there were options, but couldn't find a way to modify the file size and lock the px dimensions, so anything I tried to lower the file size (currently 521.4m) affected those dimensions. I flattened the image, and don't see anything else in the interface that I could change. What am I doing wrong? What's the right way to set dimensions but cap the file size? 

Computer: iMac, Big Sur

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2 replies

Conrad_C
Community Expert
Conrad_CCommunity Expert
Community Expert
January 25, 2021

It sounds like you’re checking file size by looking at the Image Size value in the Image > Image Size dialog box. That tells you the size it will be if left completely uncompressed, but it doesn’t take into account how different file formats and compression methods save space.

 

I’d recommend separating this problem into two parts: File size as you edit, and file size for delivery.

 

File size as you edit: Don’t worry about this, let the file be as big as it wants to be during editing. This will retain quality, and this is not the version you will deliver, so the delivery file size doesn’t matter yet.

 

File size for delivery: No matter how large it is while editing, you’ll deliver a copy that’s crunched down to fit the file delivery requirements. I created a 13500 x 13500 pixel image (90 inches at 150 ppi) at 8 bits per channel, filled it with random content using Filter > Render > Clouds, and these are the file sizes I got:

 

Photoshop (PSD) format — 498 MB (it differs from Image Size because of the content and built-in compression)

TIFF format uncompressed — 547 MB

TIFF format compressed with the LZW option — 76 MB

TIFF format compressed with the ZIP option — 60 MB

 

All of the formats above can store layers with no quality loss. Those are the file sizes for a flattened document (background layer only). Note that TIFF ZIP takes a lot longer to save than the others, so that’s something to take into account. The actual file sizes will vary depending on the content in the document.

 

If they’ll let you use the JPEG format for the final delivery version, then this is what I got with my example:

JPEG format compressed to level 10 — 5.4 MB

 

That should give you an idea of what might be possible with your own file.

    JJMack
    Community Expert
    JJMackCommunity Expert
    Community Expert
    January 25, 2021

    Many Image File formats support data compression. The bulk of an image file data is Pixel data. You Image 13,500px by 13,500px has 182,250,000 pixels Printed at a 300ppi resolution the is a print size 45" by 45" 14sq ft.  Where are you getting all those Pixels.  Why do you need a image that has so may pixels?

    An 8 bit color image with 182,250,000 pixels uncompressed pixel data is 546.75MB. A 16Bit Color depth image that size is over 1GB of Pixel data.

    JJMack
      M
      MissM2Author
      Known Participant
      January 25, 2021

      Thank you for your response, JJ. I created a new file with the same canvas size, 8 bit, and it was 500m+ blank. The artwork I'm trying to 'fix' the problem with, must print at around 90" x 90", but be between 100-128mb. Is this possible? 

      JJMack
      Community Expert
      JJMackCommunity Expert
      Community Expert
      January 25, 2021

      90" x 90" is large so it will not be view up close and personal where the human  can resolve down toe 300ppi and see fine details.   So your 7.5' x 7.5' image does not need fine detail.  I would think you image would look great printed with a 100ppi resolution  90x100x90x100=81,000,000 81MP  9000px by 9000px That  image is less than half the size image you currently use.  What format are you saving in. It looked to like you were  saving a Tif  with no data compressing. You file size 521MB this seem like an uncompressed TIFF file the number I quoted  was 546.75MB but that would decimal where 1K is 1000  your 521MB is where 1K= 1024.  First save you current image as a flat Tiff with zip compression to see how well its pixels data will compress it may taks long time to save data compression can take some time.   Try LZW compression first ite does not take too long to save.

       

       

      Where did you get all those pixels in the first place. Are the high quality pixels I do not know of a camera the has and 182MP sensor it would need a huge 1:1 aspect ration sensor and a huge heavy lens.

       

      JJMack
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