Re-saving an image over and over and over again in a lossy format (a format like JPEG that tosses some data each time you save/compress the file) slowly but surely degrades the image. This is called generation loss, and it's demonstrated beautifully in these almost painful-to-watch YouTube videos.
You’ve spent the last few hours working on the perfect photo shoot and everything went better than you could have possibly imagined. After importing the RAW files to your PC and making a few edits in Photoshop, it is time to save your masterpiece. But, what file type do you select? With over twenty different file types to choose from, we are here to break down some of the most popular and tell you a bit about their strengths and weaknesses.
At the turn of the century, the Joint Photographic Experts Group created what they considered to be the next generation of JPEG image compression. Suitably named JPEG 2000, the standard promised better compression performance with improved image quality. However, despite the standard being released fifteen years ago, why do most photographers only glance over the option when saving in Photoshop? Today, we explore the advantages and disadvantages of a file format that already seems to have become a footnote in history.
It's common knowledge that JPEG compression leads to a loss of data, but it's difficult to really visualize the extent of that loss in a photo. A keen eye will be able to tell a difference, but it's still hard to quantify it.
Tom Scott wanted to bring the reality home to those who don't already understand it. So he took the pitfalls of JPEG compression and transferred them from the world of photos, to the world of Shakespeare.
Adobe has officially added lossy compression into the latest specification (1.4) for its Digital Negative (DNG) RAW file format. The new Lossy DNG, which first appeared as a feature in Lightroom 4 earlier this year, gives photographers a middle-ground between the quality of lossless DNG photos and the small file size of JPEG photos.
Recognize the warning message above? It's what Windows XP would show whenever you tried to rotate a JPEG image 90° using the Windows Picture and Fax Viewer. If you're like me, you probably didn't think twice about it (and checked the checkbox), since you had done it many times already and hadn't noticed any difference in quality. After all, how hard can it be to turn a digital photo sideways? You just move the pixels around right?
Well, not really. The fact of the matter is, JPEG is a "lossy" compression algorithm that's geared towards storing and sharing photos without taking up too much disk space. Rotating these compressed images is usually done by decompressing, rotating, and then re-compressing. Since the re-compression is lossy (i.e. data is thrown away), this process results in slightly degraded photos (hence that warning).