Dual display

If you're a photographer who spends a lot of time on the road, the lack of screen real estate on your laptop can make anything more involved than checking emails needlessly frustrating. What you may not realize, however, is that the iPad can be used as a second monitor. And better yet, you can do it over Wi-Fi.

What you'll need:

  • Air Display app $9.99
  • iPad and Mac or Windows computer
  • Unprotected Wi-Fi network
  • iPad stand
Using the Air Display app, I can wirelessly connect my iPad to my laptop and use it as a second monitor for use in apps like Photoshop. The BookArc iPad stand shown here holds the iPad at a comfortable viewing height.

While the capability to use your iPad as an external monitor has been around since the original iPad, the Retina display of the latest version offers a more compelling reason to do so, with higher resolution than your laptop and likely a wider color gamut to boot. In the image above, I'm using the screen of my MacBook Air to house Photoshop panels while the iPad is dedicated to a full screen image view. This is a small, lightweight combo that I can travel with easily and setup anyplace that has Wi-Fi access.

Air Display

What makes this all possible is a clever little app called Air Display. After purchasing the app you download a separate piece of (free) software to install on your Mac or Windows host computer. With both the iPad and computer on the same network, simply enable Air Display and select your iPad from the pulldown menu. You can move applications, windows and documents to either screen. Air Display supports iPad touch capability by converting basic gestures into mouse clicks. You even have access to the iPad's virtual keyboard for text entry.

HiDPI mode

This setup lends itself especially well to Photoshop tasks that require a high degree of visible image detail, like sharpening and noise reduction. With the iPad's huge 2048 x 1536 pixel dimensions constrained to such a small screen area, however, text and dialog boxes are very small and hard to read.

You activate monitor sharing and configure preferences using software installed on the host computer. Choices include the option to enable HiDPI resolution mode (highlighted in red) for larger and easier to read text and graphics on the iPad.

Fortunately, for Mac users running OS 10.7 and higher, Apple provides a hidden 'HiDPI' mode which lowers screen resolution (thus making text and graphics larger) but without the pixelated results normally associated with scaling digital output to a non-native resolution. Air Display offers easy access to this HiDPI option (shown above), letting you use a 1024 x 768 screen setting to produce larger screen elements and much greater readability, with only a negligible loss in image detail.

Here you can see a size comparison between a Photoshop CS dialog box displayed at the iPad's native 2048 x 1536 resolution (left) and the same dialog displayed using Apple's HiDPI 1024 x 768 resolution (right). The scaled version maintains impressive detail without blurred or jagged pixel edges.

Earlier I mentioned that iOS devices do not recognize ICC color profiles. Well, since you're now using your iPad as a secondary display that is controlled by the OS of the host computer, you will see accurate colors on your iPad for any non-sRGB image as long as it is embedded with the appropriate color profile.

ICC compatibility

And for those who demand the utmost in color accuracy, running your iPad as a secondary monitor also means you can create a custom ICC monitor profile for your iPad, just as you would for any other connected display. Keep in mind though that this ICC profile is stored on and accessed by the host computer only, so you lose its benefits as soon as you disconnect the iPad.

With your iPad connected to your Mac or Windows computer as a secondary display, you can create an ICC monitor profile for it for maximum color fidelity. Here I'm using Datacolor's Spyder 4ELITE colorimeter and software.

While Air Display is very simple to setup, be aware that many corporate Wi-Fi networks have security features that specifically prevent the device sharing that the app needs to make all this work. But in a typical home, studio or hotel environment, you should have little problem making the connection.

Wrap up

The iPad has many fun and creative uses, as the long list of offerings in the App Store will attest. Don't be fooled, however, into thinking that it has no place in the production-oriented tasks that fill the days of both enthusiasts and professional photographers. By showing you three specific ways in which it allows you to work smarter and more efficiently, I hope you'll be inspired to use it for creating, rather than just showing off, your images.