Why JPEG?

The result of years of debate and contests in forums is:

No one has been able to tell the difference between images stored at Photoshop JPEG 12 and JPEG 10 settings, but JPEG 10 images are less than a third the size.

We tell our customers to save at JPEG 10 for psychological comfort, but for our own photographs, critical prints of million-dollar cars shot at Pebble Beach Concours d'Elegance that hang in expensive mansions, we're perfectly comfortable with JPEG 8.

In 1,000,000 photographs shipped, only a handful of people noticed a JPEG artifact. We've seen many prints returned, almost always for color, contrast, exposure, or lack of unsharp mask — hardly ever for compression.

There are three compression scales that matter:

1. Photoshop Save As... Good for saving files for print. Bad for saving for display. Scale: 1-12. In general, we recommend JPEG 10, which is lab quality.

2. Photoshop Save for Web... Good for saving for display. Bad for saving for print. Scale: 1-100.

Gotcha: Your photo will have no exif information attached if you use the save for web option.

3. IJG (Independent JPEG Group, RIP, which developed free JPEG utilities). Programmers like IJG and use it in photo sharing sites and Internet browser software. Scale: 1-100.

The bigger the number the higher the perceived quality. Mostly.

It's like calories in food. More calories = better taste. Mostly. Not always.

How could a bigger number mean lower quality? If the image had already been saved at a lower quality (say, JPEG 8) then saving it at higher (say, JPEG 10) will make it both bigger and lower quality. This would happen if your camera was set for the medium compression setting, for example, when the photo was shot.