Lightroom: Create Wallpaper in Lightroom

Many smart photographers offer free backgrounds, aka wallpaper, to people and potential clients. What's a wallpaper? It's an image used as a background for a computer, a tablet, or a cell phone. The problem with the wallpapers is that you need to offer a wallpaper at the resolution of the computer/device or it will look bad. Ask the owners of the iPad 3, aka the new iPad. Many apps and wallpapers do not support the new resolution and look terrible on the iPad 3.

Sit down, strap your seat belt, there will be some math involved.

  • Select the photo or the photos
  • Print and output to JPEG. Sounds simple but remember the math…

For “regular” computers, this means desktops and good laptops, you should set the resolution to 96 ppi. For the iPad 1 and the iPad 2, the resolution is 1024 by 768 pixels at 132 ppi, For the iPad 3, aka the new iPad, the resolution is 2048 by 1536 pixels at 264 ppi. Many Netbooks have a screen resolution of 1024 by 768 at 72 ppi. The iPhone 4 has a resolution of 960 by 640 pixels at 326 ppi.

You will need these numbers. What does this all mean? It means that you will have to make a few wallpapers of the same image for the different sizes and resolutions.

The math is for the print size, and it's done once you have decided on the resolution:

This is a simple example. Nobody uses the resolution of 100 ppi but it's great for a demo. For 1980 by 1080, the Custom File Dimensions will be in inch:

  • The width will be 1980 divided by 100 = 19.8 inch
  • The height will be 1080 divided by 100 = 10.8 inch

If the resolution is 96 ppi, with 1980 pixels by 1080 pixels, the Custom File Dimensions will be in inch:

  • The width will be 1980 divided by 96 = 20.6 inch
  • The height will be 1080 divided by 96 = 11.2 inch

For the iPad 1 and 2, the resolution is 132 ppi, with 1024 pixels by 768 pixels, the Custom File Dimensions will be in inch:

  • The width will be 1024 divided by 132 = 7.8 inch
  • The height will be 768 divided by 132 = 5.8 inch

For the iPad 3, the resolution is 264 ppi, with 2048 pixels by 1536 pixels, the Custom File Dimensions will be in inch:

  • The width will be 2048 divided by 264 = 7.8 inch
  • The height will be 1536 divided by 264 = 5.8 inch

Notice that also the Custom File Dimensions are the same for iPad 1, 2 and 3, but the wallpapers are different because they are different screen ppi.

  1. Select the Print to JPEG
  2. Set the File Resolution to the desidered resolution 72, 96, 132, 264, or 326
  3. Set the Color Management to sRGB
  4. Set the Custom File Dimensions to what you have just calculated

I usually select the Layout Style to Custom Package and I use the preset, Maximize Size, before setting the Custom File Dimensions.