Quickly sign any document with Preview

PreviewIconXIf you need to sign a form or other document in OS X, look no further than Apple’s Preview application. Letters, contracts, and other documents are progressively migrating to digital media as PDFs; however, you may still be required to stamp them with a personal signature. One approach for this is to print out the forms, sign them, and then scan them back in to your system; however, another approach is to paste an image of your signature on the document.

To do this, you can scan your signature and then crop it, followed by pasting it or otherwise combining it with your PDF, but this can be cumbersome, especially since the scanned image might not have transparencies around the signature, resulting in obscuring part of the PDF. To overcome this, you can use the signature feature in OS X’s Preview application, to save your signature and then neatly embed it into any PDF.

Preview signature tool

Click this signature tool to create a signature (click image for larger view).

First, sign your name on any sheet of white paper, and then do the following:

  1. Open a PDF in Preview
  2. Press Shift-Command-A to display the annotation tools
  3. Click the signature tool, and choose the option to create a new signature using your Mac’s FaceTime camera
  4. Hold your signed paper up to the camera and align the signature with the blue line on the display
Preview signature capture in OS X

Holding a signed paper to the line will have the system capture it for use in PDF documents (click image for larger view).

When you do this, you should see a captured image of your signature appear in the preview window, and you can then click the button to accept the signature and save it for use after Preview quits.

With the signature saved, you can then select it from the signatures annotation tool and click anywhere in your PDF to place it. You can then move and resize it accordingly, and it can then be saved or printed with your PDF.

Preview will not only save your signature in this manner, but will also allow you to make multiple signatures and keep track of when each was created and last used. This can be convenient for allowing some variety in your signatures, and update it as it changes over the years.

5 thoughts on “Quickly sign any document with Preview

  1. JRobert

    How photographic signing not wide open to abuse, specifically, by cut and paste? Forging with ink is at least difficult; any idiot with a scanner can forge photographically. At least if you’ve never made & confirmed/accepted a photo of your signature you’d have _some_ defense in the event someone else copied your inked signature. Secure digital signing technology already exists. Why should we adopt any less?

    1. Aram Fingal

      I was going to mention digital signatures as well. However, this won’t happen without some real effort. The cryptographic basis of digital signatures is not an issue. That’s plenty strong. The problem is that digital signatures depend on the ability to reliably match a person’s identity with their public key. There are two ways to do that. One is the certificate authority model where a central service takes care of an identity database and the other is the web of trust model where people verify each other without a central authority. The certificate authority model requires money but less effort on the part of ordinary users. A web of trust is the other way around. It doesn’t require money but it does require that end users do their part to make the whole system work. So far neither model has even come close to reaching critical mass.

      I reason I think that the situation could change is a combination of the fact that the need for digital signatures is greater than ever and the fact that the ordinary person is a lot more sophisticated using computers and other devices than they were years ago, when digital signature technology was first introduced. The conventional wisdom is that doing public key infrastructure (PKI) correctly is difficult and any mistake can compromise security. I don’t disagree with that. I do think that wide adoption of PKI is likely to go badly at first but, most likely, people with stick with it and get it right eventually.

      Two situations, in particular, where we really need to adopt PKI are email encryption and social networking. Email is the only major form of personal communication on the internet which isn’t already encrypted end-to-end. Social networking, in my opinion, should not be controlled by a central web site like Facebook. It should be a peer-to-peer network where the underlying model is a web of trust. In other words, when you friend someone, the under-the-hood implementation is that you sign each others public key. This not only supports the social network but also provides the infrastructure needed for verifiable signatures of documents and messages.

  2. tere

    Any way to import Preview signatures from one computer to the next or store them in iCloud so they are accessible from multiple computers?

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