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garys53312489
garys53312489
Participating Frequently
June 18, 2021
Answered

Changing PDF to bitmapped tiff without changing resolution or size.

  • June 18, 2021
  • 2 replies
  • 4627 views

  Background: We have lost our RIP server, we don't print a lot of long run envelopes anymore... but do.

Our imagesetter requires 2400 dpi one bit tiffs to burn a plate.

  After a lot of messing around I have finally figured out how to do the above, and make a 1 bit tif the platesetter will accept. However... I can't get the images to stop reducing slightly.

 

 Example. 

Original file is a PDF of a black only PDF. Page size is 13.33 x 18.86 in. (It MUST stay that size.)

And the PDF is 2400 dpi. (Must be 2400 or platesetter will reject)

  I open the PDF in photoshop, no matter what I do it changes the canvas size to 13.33 x 13.33. Even though in the PDF I changed every page box to 13.33 x 18.86. No matter what I do it make sit square.

Fine. So after opening, I change the canvas size to 13.33 x 18.86. 

  I then change the image mode to bit mapped. And save as tiff.

  The result is a 2400 dpi tiff, the size is correct as 13.33 x 18.86... however the image itself is approx. 30% or so reduced in size.

  I'm thinking this is happening when opening the PDF and it changes to 13.33 x 13.33.

 

  Kind of stressing. A person will lose their job if I can't figure this out. We are not going to spend the money on a new RIP, we will outsource the long runs...and a guy loses his job.

 

Thanks for any assistance.

    Correct answer TheDigitalDog

    Try ensuring the TIFF is is exactly the correct pixel dimensions. Exactly. For example, 13.33 x 2400 is 31,992 pixels (we're talking a big file here)! You need exactly 43,992 pixels on the other dimension. The resolution tag can and should be 2400 but the important attribute is the pixels. You may need a blank document exactly this size first, save as the TIFF you need, then attempt to 'rip' the PDF in Photoshop and place it into that document. 

    2 replies

    TheDigitalDog
    TheDigitalDogCorrect answer
    Inspiring
    June 18, 2021

    Try ensuring the TIFF is is exactly the correct pixel dimensions. Exactly. For example, 13.33 x 2400 is 31,992 pixels (we're talking a big file here)! You need exactly 43,992 pixels on the other dimension. The resolution tag can and should be 2400 but the important attribute is the pixels. You may need a blank document exactly this size first, save as the TIFF you need, then attempt to 'rip' the PDF in Photoshop and place it into that document. 

    Author “Color Management for Photographers" & "Photoshop CC Color Management/pluralsight"
      garys53312489
      garys53312489Author
      Participating Frequently
      June 18, 2021

      Yeah they are pretty big until you export with LZ compression, which makes it about 300kb... but the raw file in Photoshop is 1.6 GB before compression... luckily I have a good Mac so it isn't too slow between steps. 

        You might have an idea here, and I see what you are saying. By creating the blank tif with the correct size, and then placing the art in afterwards, and then re-exporting again might work.

        Thanks!

      D Fosse
      Community Expert
      D FosseCommunity Expert
      Community Expert
      June 18, 2021
      quote

      Yeah they are pretty big until you export with LZ compression, which makes it about 300kb...


      By @garys53312489

       

      Something's completely off here. You don't seem to realize just how big 13.33 x 18.86 at 2400 ppi is! It's not big, it's a gigantic file, much bigger than most people will ever need, for any purpose.

       

      There's no way you can export that and end up with 300 kB. That's compressing an airplane to fit in a matchbox! In that case it has to be massively downsampled and probably 99% of the original pixels discarded.

       

      You need to get your dimensions straight first. This can't be right. Find out how many pixels you need. Size and ppi are indirect measures to Photoshop. It works only with pixels.

       

      Pixels per inch (ppi) is not a standalone measure. It's an equation: total number of pixels/size in inches = ppi.

      jane-e
      Community Expert
      jane-eCommunity Expert
      Community Expert
      June 18, 2021

      If you have Adobe Acrobat Pro, try one of these two methods:

      • Single image
        Selection tool > right click > Save image as... > save as tiff or jpeg

      • All images
        File > Export To > Image > jpeg, tiff, or png

         

       

      "Even though in the PDF I changed every page box to 13.33 x 18.86. No matter what I do it make sit square."
      How did you make this change in the PDF?

       

      ~ Jane

       

      garys53312489
      garys53312489Author
      Participating Frequently
      June 18, 2021

      You can't export a 2400 dpi resolution PDF with that page size in Acrobat Pro.

      One of the many things i have tried.

      Thank you though.

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