Preview: PNG vs. PDF

Question

Level 2

256 points

Preview: PNG vs. PDF

I ask because I want to make sure I have this right. It seems that Preview won't allow me to do my editing in PDF but requires a PNG file.

I scanned a typed document onto my hard drive. Image Capture saved the the image as PDF. I opened the document in Preview Version 5.0.3 (504.1). I wanted to delete some text. I used the "Select" tool to select the text. But nothing happened when I pushed the Delete key. The only way I could excise the text was to save the scanned image as a PNG file. Then Preview deleted what I wanted.

Is that correct? Does the Delete key not work on a PDF file?

Mac Mini, Mac OS X (10.6.8)

Posted on Jul 29, 2013 2:03 PM

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Answer 1

baltwo

Level 9

62,362 points

Jul 29, 2013 5:56 PM in response to R_55a

IIRC, you have to scan the doc as text. Then, you can edit it and finally save it as PDF. You can't edit the text in images.

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Answer 2

R_55a Author

Level 2

256 points

Jul 29, 2013 6:19 PM in response to baltwo

Well, actually, I treating the text as image not as text. IOW, I scan the document into an image format. PDF is my default scanning format. What I get is a PDF file of an image. Hypothetically the image could be of a famous painting or a zoo animal or any graphic. What I am working with here, though, is an image of a printed page. It is a PDF of a printed document. It is not a word-processing document. I have not used an OCR to scan the document; I have simply reproduced it as an image.

What I want to do is to excise certain parts of the image. Again, if I had scanned a photograph of a fish, I could use Preview to remove a fin or two. Similarly in my image of a printed page, I can select a certain portion of the image and delete it. Because the document is the picture of a printed page, what I delete is a word or set of words. It is still an image--an image of words.

As I say, I could not delete a portion of the PDF file, but the deletion worked nominally when I converted the document to PNG.

Is that how Preview is supposed to work?

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Answer 3

Kurt Lang

Level 9

57,984 points

Jul 29, 2013 7:19 PM in response to R_55a

A PDF is a container file that can hold various types of data. When you try to edit an embedded image, you cannot do anything to it since it's a component of the PDF.

There's no advantage at all to scanning to a PDF since you're just stuffing one file type inside another on the fly. Even if you had Acrobat Pro, you couldn't do it.

Since a scanner always produces a pixel based raster image, save your scans as that file type so they are fully editable. TIFF is best since it's lossless, but takes up more space. JPEG saves disk space for the same total number of image pixels, but is a lossy format. Which only compounds the loss each time you open and resave the file.

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Answer 4

baltwo

Level 9

62,362 points

Jul 29, 2013 7:28 PM in response to R_55a

Sorry, I thought you wanted to edit text within the pdf file. I think Kurt's given you the answer you're looking for.

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