Scale carefully

How do people see your images? Do you ever wonder?

So maybe you shoot at a gazillion megapixels. Or at 12 megapixels. Or even at a lower number: say 6. (That would be 3,000 pixels wide x 2,000 pixels high).

Great when you want to print. But when you want to use your image at a lower resolution, like when emailing, or posting on the Web, then what do you do?

After you create it (whcih you always do at the highest pixel setting), you then need to “scale down” the image to the right size, that is what. And you can do it, or you can let your email program or web site do it, which is even easier.

Easier – but not better. When you scale down an image, you can do it in many way.

Just now I uploaded a image to Facebook. A large-ish image. And it looked like this, after Facebook scaled it down to its required size of 720×480 pixels:

Bird bathing, by Michael Willems

Bird bathing (Aug 29 2010)

(You can see it’s not great, but to really see this, you need to see it full size by clicking on it, since WordPress also reduces the size that you see there!)

So then I did it myself in Lightroom before uploading, to exactly 720×480. Lightroom, when scaling, first applies a proper scaling algorithm, and then sharpens the image – which you need to do, since reducing the size blurs it slightly.

The Lightroom-scaled version looks like this:

Bird bathing, by Michael Willems (scaled well)

Bird bathing (scaled well)

(Again, you need to click and see at full size. In fact, better that you save both to your desktop an then flip between them there.)

And you will see that the version I scaled is much better than the version Facebook roughly scaled down.

So remember: pixels are everything. When producing output, find out how many pixels wide and high it should be, and produce it in that size in Lightroom (or Aperture, or Photoshop: whatever you edit in). And sharpen as the very last step.

Some suggested pixel sizes:

  • Facebook: 720 x 480
  • Email: largest dimension 1200 pixels
  • iPad: 2304 x 1536
  • Small email-sized: 800 pixels widest dimension

And remember, DPI does not matter if you specify the pixels. I set it to 300, but you will see that the file is identical whatever you set it to, as long as you can specify the actual pixels (which you do, in, say, Lightroom).

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