Cloaked characters in a PDF file

[Jeff7]

I say cloaked, because it seems that the letters are in fact present, but they're just invisible. Only the clipboard can reveal them.
What I've got here are two separate files, one a series of schematics for a monitor, the other a service manual with schematics in it. In both of them, on the schematics, most of the capital letters, and some numbers are not appearing. However, when I highlight the area (which still does not reveal them), copy it to the clipboard, and paste the contents into another application, right there are the missing letters.
Example:
If Acrobat (or Ghostscript for that matter) display "24", but it should say "R248", I highlight the area - the blocks before and after the 24 - and copy it to the clipboard. Now, in Word, Notepad, whatever, I paste. Instead of getting " 24 " or "24", I get "R248" like it's supposed to be.

So, now I just need to figure a way of revealing these invisible numbers. Suggestions? I'm using the latest version of Acrobat (and Ghostscript); all the fonts in the page appear to be embedded within it too.


Edit: GIF image of an example of the error. The text highlighted should read "R248" - but instead, only the "24" is visible.

Edit #2 - Found two "solutions". One is thanks to dakels, who has offered to redo (rerender?) the schematics. The other is thanks to a reply, that took awhile to get to me, from the organization where I purchased the service manual. It seems that they combine the original files from the monitor manufacturers, so that they are all just one big PDF. Something must have been done wrong in the full 68-page file I was given. So, they linked me to the original ZIP file, which contained several unedited PDF files, each only a few pages long. But they all render the pages without errors. R248 shows up as R248, etc.

 

[Aso]

Is it possible to see this PDF file? How are you creating this PDF file or was it just sent to you that way?

 

[dakels]

this is usually a display problem with fonts used. The type data is there but possibly the display graphics are corrupted in some way or there is a conflict. It can also be certain settings with the way the PDF was made and settings on your local machine. The antialiased PDF text can sometimes have display problems like this. Most of the times changes need to be made on the creation process, usually a better or more compatible font or saving compatability or the app which created the PDF. Sometimes changing the magnification will help, otherwise not alot you can do on your end unless you use a program that can edit PDF's. Good programs would be Illustrator or Indesign. You can also try using MS Word to open the file. Using these programs, especially the Adobe apps would at least allow you to preserve the photo+type layouts, although you may not have a matching font if it asks for it.

 

[Jeff7]

Originally posted by: Aso
Is it possible to see this PDF file? How are you creating this PDF file or was it just sent to you that way?

Schematic file, 6.1MB

Download it in its entirety, then search for R248. It will highlight a section of text (at least on my PC), that just says "24" in about the middle of a schematic diagram on page 4.

I'm not creating the file - this is how I downloaded it. There's two files that this occurs in actually - the schematic file above, and the full service manual.

Sometimes changing the magnification will help, otherwise not alot you can do on your end unless you use a program that can edit PDF's.

Magnification has no effect.
And I'm guessing that editing PDF's requires really expensive stuff from Adobe, right?


Also, this problem occurs on more than one PC - my laptop also fails to show the numbers.

I did use Ghostscript to export the PDF to a Postscipt file, which didn't do a whole lot, as I don't have anything that can open a postscript file in a usable format. However, I did open it with Notepad, and I found the texts, all intact, within the file.
Using Ghostscript to view the PDF though showed the same errors - certain letters and numbers would not appear. Another example is a tag in the schematic that says "DEFLECTION" - only the "N" is visible out of all of that.

 

[dakels]

Its a problem with some of the embedded fonts. Whoever made the schematics used some crap type 1 and TT fonts which didnt distill properly causing the display error you see. It was a problem with the PDF creation thats to my knowledge is not going to be easily worked around or repaired without rebuilding it and replacing the fonts. If you have Illustrator you can open it up page by page and substitute the fonts, then resave as a PDF. Replace with non serif fonts like a helvetica or arial. Once you are done with each page you can then join them as a multipage PDF in Acrobat Pro. With the right software and a fairly quick machine it can be done in about 15 minutes or less.

 

[Jeff7]

Here's what's used in the schematics file:

Swiss721BT-Roman (Embedded Subset)
Swiss721BT-BoldItalic (Embedded Subset)
Arial (Embedded)
Swis721BT (Embedded)
Arial-Bold (Embedded)
Swis721BT-Bold (Embedded)


Interstingly enough, the first two are Truetype, and the others are Type 1.

Best bet then - post a request, and hope someone with Illustrator will see it, and re-do the files?