How to edit and scale a locked PDF-file

Discussion in 'Tips, Tutorials & Tools' started by Leif Oh, Jul 18, 2004.

  1. Leif Oh

    Leif Oh Member

    Most probably I've just reinvented the wheel, but yesterday I stumbled onto a rather elegant (if I may say so myself) way to convert a locked pdf-file to something which you can edit, scale, and rearrange in any ordinary graphics program, with the same kind of quality control as in scanning, and just using the ordinary freeware Acrobat viewer that comes with any web browser.

    A good graphics programme will open and convert an unlocked pdf-file, but not a locked one. The basic idea to overcome this obstacle is to "print" the locked pdf-file to a post-script (PS) file, and then open that in your ordinary graphics programme. You will not get a file that can be edited in a vector-based application like Adobe Illustrator, but rather the same kind of file you would have got from scanning a printed paper original.

    For this to work, however, you have to identify some special buttons in your print menu. Here's how to do it in two simple steps (with an even better alternative for those who have a full version of Adobe Acrobat).

    1. Open the pdf-file in your Acrobat viewer. Choose a laser writer printer (even if you don't have one). You need that print driver in order to create a postscript (PS) file.

    In the print dialogue window, choose "Print to file". If you just left it at that, however, you would get a PS-file which Photoshop or similar graphic programs would not be able to open. Therefore, you will have to find the special menu, in the print dialogue window or elsewhere, that says "Adobe Acrobat".

    In that new dialogue window, find the "Print as" option, and choose "print as an image" (instead of "print as a PS file"). This is the crucial step, I found.

    Now "print" the first page of your pdf-file. The result will be a PS-file on your computer. The process will take time, since the file will be some ten thousand times larger than the simple PS-file you would have got otherwise. It seems to be just as large as a full Photoshop file would have been.

    Repeat for all pages of your locked pdf-file.

    What you've got now, is a set of PS-files that Photoshop (or similar graphics programmes) can use in much the same way as if you had a printed paper original and wished to scan it, with the advantage that you don't actually need a scanner - it's all done on the computer!

    2. In your graphics programme, open the first of the PS-files. In Photoshop at least, you now get a dialogue window which asks you to specify a number of size and resolution parameters. This is good, and you should not bypass this window hastily, because this is were you decide on scale and resolution, just as if you were about to scan a printed original.

    (If you do not get this prompter, you'll have to make similar adjustments in the file that soon will open in your programme.)

    If you are satisfied with the scale, leave everything concerning size of the image alone. As for resolution (dpi), choose what you would have used in scanning. I use 300 dpi to ensure that there's no loss of quality.

    Others, I understand, regularly go to the extreme of 600 dpi. Others still, may be satisfied with the standard 72 dpi, which is probably OK as long as you go with the original scale (in which case your files will be much smaller).

    If you want to enlarge (scale) the original, however, I strongly recommend stepping up to at least 150 dpi.

    Scaling is done by changing one of the size parameters (width or height of image) to "percent", while checking the box "keep proportions". I build models in 1/25, so if the original scale is 1/32, I insert the value 128 percent. (See the article on "Scaling" on this site.)

    Finally press "OK" and wait while the graphic programme "scans" the PS-file. In a moment's time you will get a glorious copy of the locked pdf-file at your own chosen scale and resolution.

    Save in your prefered format (psd for Photoshop, as an example, or jpg). Repeat for all of your PS-files.

    What you've got now is a set of new originals which can be cropped, rearranged, or even recoloured, just as if you had scanned a printed original, and with no loss of quality!

    Proceed as if you had just scanned a printed original. If you have enlarged the original, you will be sure to need rearranging parts to fit into your standard paper size. (Again, see the article on "Scaling".)

    3. A final word for those of you who have a full version of Adobe Acrobat: You are in the happy position of having the option to speed up the process somewhat. In the full version, you are able to use the option "Export as PS or EPS", which turns out to be rather handy.

    I do not profess to have the slightest idea what the difference in format is, or even what EPS means. But some trial-and-error experiments reveals that you should use the EPS format. Also, be sure to choose "Level 3 postscript" (I think that has to do with colour printing, since level 1 will result in a black-and-white image).

    Export the whole document to EPS with these setting. You will automatically get all the pages in separate EPS files. This eliminates "printing" each page separately to a PS-file. A major advantage is that these files will be very, VERY small (think 400 Kb instead of 40 Mb!), which means that you can well afford to save them in order to be able to make a second "scan" at a different resolution, should you find that desirable at a later date.

    Proceed as per above and open these EPS files from within your graphic programme. From that stage on, the process is the same as above.

    Leif Oh.

    PS. I would like to reiterate the word of caution I've seen on this site. The files you get this way are clearly derived from a copyrighted original and should be used strictly by yourself, just as if you had scanned a purchased paper original.

    The subject came up again in a discussion on a similar technique for dealing with locked pdf-files. In comparison to that technique I believe that the method outlined above provides greater control over, and increased quality of the output, while not being more tedious.

    A comparison of quality

    Here's a screenshot which enables you to compare the quality of the original locked pdf-file (left) and the "scanned" and scaled Photoshop file. I have used a section of the Avia B-534 recently announced on this site as an example.

    At left, the original pdf-file is shown at 400 percent magnification to reveal the quality of the original.

    At right, you can see my "scanned" copy at 300 dpi and 128 percent scaling (to 1/25), shown at what I believe is close enough to a similar magnification (it might even be slightly larger). As you can see there is no discernible loss of quality.
  2. DeWayne

    DeWayne Member

    Thank you. I don't like pass worded files and though I respect the desires of others that use them, to me, they are a nusiance.

    My system differs a little in that I can't find any reference to dpi or print to Adobe. It does, however, print to EPS in a .prn file that is read by Illustrator. Neat trick and again, thank you.

    PS: Now; how can you do this and get vector out of it? DGB
  3. Leif Oh

    Leif Oh Member

    Well, I'm not so familiar with vector, and the file I tried the method on clearly wasn't vector. But how about making an experiment?

    Since you were able to open the print files from a pdf in Illustrator (something I didn't manage to do; probably lack some plug-in or something), why not try the method on a pdf-file you know contains a vector image, and see what happens?

    If you want to go the whole hog, lock the file beforehand...

    Interesting to see what happens, right?

  4. ButchPrice

    ButchPrice Member


    EPS stands for Encapsulated Post Script.
    (What exactly constitutes "encapsulation" is
    beyond me however)
    I assume some kind of post-script container
    that adds some additional or special features
    to a .ps file (post-script file).
    I don't have Illustrator, so I don't use it
    much, yet.
    I am preparing to install freeware GostScript
    and the GS viewer to see if this will permit me
    to view / print .ps files
  5. charliec

    charliec Active Member

    EPS was an extension to the Postscript specification to permit Postscript to be transported between systems without the target system needing to have a Postscript interpreter. The encapsulation part is wrapping the postscript so a system without the capability to interpret PS won't attempt to. Part of the EPS spec allows for a bitmap preview image of the PS part of the EPS. EPS has been pretty much superceded by PDF - I can remember using EPS export from a scientific graphing package to insert into a Unix word processor about 10 years ago. Raw PS couldn't be imported into the word processor but EPS worked fine. The postscript part of imported EPSs didn't get interpreted until
    the document was printed.

  6. Maurice

    Maurice Member

    Continuing my efforts to ease the toughness of life in Indiana. :D

    An alternative to the first part of Lief's method is to print the "printable but otherwise locked" .pdf file through a printer emulator which will then produce an "unlocked" .pdf file.
    If the content of the original is in vector format, the output .pdf should be also, and using Win2PDF it will often be smaller.
    Bitmap content in the original can cause the output size to blow out especially when the dpi of the output is adjusted to a level that preserves the definition of the original. This certainly happens with the B534 files but the output is still as good as the original and editable in the usual ways.

  7. Old Ranger

    Old Ranger New Member

    Getting .pdf files into editable format in PSE

    You folks have probably discovered this long ago, so I apologize if I'm restating the obvious.

    At work we were going crazy trying to get a picture in a .pdf document into a Power Point slide. We only have the free Adobe Acrobat Reader.

    One of my coworkers told us to try this: First go to the Control Panel -->Display-->Settings and increase the screen resolution as high as it will go. It will look a bit strange and almost minaturized.

    Open the .pdf file and maximize the window size, putting your "target picture in the center and zoom in as big as possible.

    Now hit "Alt-Print Screen". This essentially takes a snapshot of the open window only (not the whole desktop as a "Print Screen" would) and puts it into some kind of buffer as an image - probably as one of the file formats mentioned above.

    Open Photo Shop Elements and select File-->New-->OK. After the new .psd files opens, hit Cntl-V or "Paste". The Window captured by the "Alt-Print Screen" appears and it can be saved to anoter format, edited, scaled, colored, etc. - like any other graphics file. I generally save it as a .psd, then return the screen to it's normal resolution so I can see what's going on!

    With this method, as long as you can open the file, it can be saved to another format and edited. It has been successful with P Model and Trotskiy files.

    Hope this helps.


    The Old Ranger
  8. jleslie48

    jleslie48 Member

    I use ghostview and ghostscript.

    you make a .eps file by installing a fake PS printer on your computer with the port being a file.

    print the pdf using the above printer, generating a print image.

    use ghostview to read the .eps or .ps file, and use it's convert routine to convert page by page to jpg, or bmp, or whatever, at up to 600 dpi.

    Ghostview can even take .ps files that aren't protected and make pdf's out of them!!!

    All for free. google for ghostview.

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