Previous 1 6 7 8 9 10 Next 227 Replies Latest reply: Jul 13, 2014 1:54 PM by Jawadelanis Go to original post
  • lapaki4 Level 1 (0 points)

    Well, if I have it right you are getting a > 90% file size compression, I'd say that is quite a compression!

  • hotwheels 22 Level 1 (0 points)

    There is something badly wrong with these filters.


    I just opened a 10 MB pdf file from SIGgraph in 2008 and applied this filter and it has caused all the images to become unreadable and a green color. Does anyone know what is up with this?


    I am using WhatSize to scan my hard drive for all my pdf's larger than 10 MB and it is going to be a disaster if this set of filters is compressing them in some way that makes them unreadable.


    Can anyone explain what these filters are doing and why it is happening?


    People are going to be *trashing* very important data with these and they won't know it...


    - Jon

  • hotwheels 22 Level 1 (0 points)

    No. I have pdfs that /range/ from 10 MB to 900 MB. I also have pdf's that are smaller. I am trying to DOWNSIZE the larger ones. I did not downsize the 900 MB file down to anything.


    In this case I have a 33 page pdf from image scans and it is 66 MB. This is too large to email. It is too large for anything. Forget the fact that I have one that is almost a GB.


    The point is two-fold.


    1. how do i get this down to a manageable size and MORE IMPORTANTLY

    2. Why does using this filter on a 10 MB sized pdf TOTALLY TRASH the images?


    I'm slowly walking through my hard drive downsizing pdf's only to find out that I am trashing - like destroying - my data.


    Is there a paid solution to this because this is a big problem. Do I have to buy Acrobat X for 600 US to get out of the mud on this??

  • Christina Rodriguez Level 4 (1,360 points)

    Are the images CMYK? Or Grayscale? I don't think it is an issue with the filters, rather preview itself.


    I know because I have tried to downsize pdfs that contain cmyk images, and the resulting saved image looks a bit as it has been inverted. Also happens with grayscale images.


    I have also exported PDFs from Indesign, and when opened in Preview, grayscale images are inverted... however when I open in Acrobat, all is well....


    So I think it is a glitch.

  • hotwheels 22 Level 1 (0 points)

    Hi Christina.


    Bingo. I think I saw one other post on this thread that was mentioning something similar? I think I also saw it on grayscale images as well but I am not technically savvy enough to figure out what is going on. So you are saying that this is just a glitch that is /restricted/ to Preview /showing/ me the pdf or are you saying that it is also some kind of glitch with the filter in some way?


    Also, can you please give me some good technical or experience-based advice on what filters to use on pdf's that I want to be professional quality? Is this dependent upon what /kind/ of images I have in my document somehow?



    It lists "low" then "average" then "low" then "average" from 600 dpi to 75 dpi with 150 dpi average as "standard compression" and I have to assume that "low" has something set lower than "average"? Is this with respect to the images or I guess somehow something other than dpi is reduced in the whole document?


    What about a recommendation for full color pdf's that you want to present professionally...?


    Thank you!

  • hotwheels 22 Level 1 (0 points)

    Hi Cristina.


    I am not so happy to report that Acrobate reader 9.4.5 cannot see these images and that they are inverted (I think that is the correct term and it appears to be what has happened). They no longer read correctly and I have to go back to Time Capsule and manually find each pdf that I just ran through the "150 dpi AVERAGE COMPRESSION" filter. Thank god I didn't get to the point where I Automated this with automator because I'd really be in a ditch. It's trashing my data.


    Can someone from Mac get on here and tell us what is going on with this issue and how to fix it?


    I have pdf's that are almost 1 GB and I have a cumulative pdf's that must be in the 50 - 100 GB range and I need to fix this in a way that doesn't trash my data.


    Is there some bug in the 150 dpi filter that doesn't exist in the others? Is there a higher setting that won't do this? Is there a place for me to post this 10 MB pdf (which I received btw so I didn't actually make this one myself) so that others can test it?



  • royfromwest allis Level 1 (0 points)

    Hi Jerome. I tried to access the filters but got an error message:


    Account error: mising locator, therefore cannot get at them.






  • hotwheels 22 Level 1 (0 points)

    Anyone know for a fact if this script leaves the originals in the Trash?


    I need to recover my data apparently and it will be much easier finding the ones that were changed in Trash instead of going to my Time Machine and finding them manually.



  • Christina Rodriguez Level 4 (1,360 points)

    No, it does not leave them in the trash. It saves over them... Which is why you should SAVE AS when ever saving a lo-res version of a PDF... I do not know if perhaps the originals are left in a hidden folder.


    In terms of the Acrobat Reader, if you saved the PDFs in Preview, then yes they will look just as bad in Acrobat. What I had mentioned was the fact that if I save a PDF out of a program, such as Indesign with grayscale images, when viewed in Preview, they look bad, but opened in Acrobat they look perfect.


    In regards to resolution...


    600 dpi is too much, unless you were printing the images @ double their size...


    I would say that for archival purposes, 150 dpi is fine if printed lets say on an inkjet or laser printer... It would not work for printing on a press, which requires 300 dpi...


    It all depends what your PDFs are for.



  • hotwheels 22 Level 1 (0 points)

    Hi Christina.


    Thanks. I can go with 150 dpi. I'm not sure where the 600 dpi came from unless I was talking about the colorsync profiles that were available.


    Anyway, I am seeing that my TIFF scans from my HP scanner are 10 MB each (?!) while my screenshots at the same 8 1/2 x 11 at 72 dpi are only 150 KB each? Is it possible there is some kind of conflict in mac or with my HP with respect to TIFFs?


    Also, the lowdown here is that I /can/ downsample EVERY SINGLE ONE of my pdfs to 150 AVERAGE COMPRESSION using these filters and that the only thing I need to watch out for is viewing them in Preview because it will show me a corrupted version of the images and if I /do/ view them in Preview I have to be careful not to save them because if I do this I have permanently corrupted them?


    I mean, I am opening them in Preview to save them out with these filters but I have to check them in Acrobat to see if the images look and read correct is that it? Yes?


    It's a very dangerous bug to have Preview corrupting pdf's...Is there anything else to watch out for?


    Thanks a ton for the help here.


    - Jon


    BTW. I have Time Machine so I think I will just open everything I downsampled in Acrobat, see if they look good and if they don't I will recover that file from Time Capsule. I mean, the point for me is that I can't keep 100 GB of pdf's around on my had drive which is why I need to downsize all of these.

  • hotwheels 22 Level 1 (0 points)

    make that "I will just open everything downsampled in Preview..."

  • BDAqua Level 10 (122,202 points)
    I am seeing that my TIFF scans from my HP scanner are 10 MB each (?!) while my screenshots at the same 8 1/2 x 11 at 72 dpi are only 150 KB each?

    Screens are typically 72, 90, or 100 DPI, Scanners can typically scan at 200, 300, 600, 1200, 2400, or 4800 DPI, so scans will be far larger, but more closely matches Printer resolutions.

  • Christina Rodriguez Level 4 (1,360 points)

    Depending on the resolution (dpi) you scanned your image at (what BDAqua mentioned) and with what compression you saved your tiff: LZW, Zip or Jpeg, will determine it's size.

    Jpeg compression typically results in the smallest file size... however, if you continually open your tiff and re-save, it will gradually lead to quality loss.


    72 dpi has a lot less information than 150 dpi or 300 dpi... so it weighs less.


    but I would not use 72 dpi for anything that will require reading/printing in the future. keep it at least at 150 dpi, 100% size.


    You can save as a pdf with jpeg compression which will decrease it's file size dramatically compared to zip compression.


    To further illustrate, I found this image at:


    The original image is 7.206" x 5.46"... Here's is what happens when I reduce it's resolution (technically it is still the same size (7.206" x 5.46) (click on it to view larger)


    HIGH-LOW res 2.jpg


    Now, what really happens when I reduce the resolution:


    HIGH-LOW res.jpg

  • hotwheels 22 Level 1 (0 points)

    Hi. Thank you.


    Sort of a new world being able to organize my images in Aperture so I will have to take a closer look at this. But I guess what I was driving at was that the 8 1/2 x 11 images that I see on my screen at 72 dpi are readable and certainly they seem readable enough to put ten of them together into a ten page pdf and to then mail to someone. Apparently if I do the same on a mac with my scans that are 10 MB each, I end up with a pdf that is 100 MB large and I can't email this.


    10 MB to me is a very large file size for something I am using for reference and I guess it means that I need to dumb down the resolution on my scans to 150 dpi to lower this. Because right now I have about 100 GB of space on my hard drive taken up with pdf prints of scans that I have taken - and this apparently means that I also have 100 GB of space taken up simply with the IMAGES that were then put into these pdf's which probably still reside in my Scanner Output folder.


    Does that make sense? I mean, I am trying to do a final sort of my images from windows in Aperture (and deciding how to handle screenshots and scans - in or outside of Aperture?) but I am realizing that I have created a huge hard drive suck with the scans that I have which has been /doubled/ by the fact that I printed them to pdf.


    My recollection in windows was that I never had pdf's print so large even if the images /were/ large but this - I am coming to realize - was probably a function of my using an Acrobat product to print these? And on mac I actually have to go back after prining them in Preview to run a filter on them to downsize them?



  • Christina Rodriguez Level 4 (1,360 points)

    Do you have Photoshop?

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