JPEG is the photo file format used online. It is also known as “JPG” and “RGB JPG.”
“Images must be RGB JPG format only.”
“We require JPG or JPEG files for images…”
“Camera RAW files … [are] less desirable file formats…”
— U.S. Library of Congress
Also known by the file extension “.JPG”
JPEG is an acronym for Joint Photographic Experts Group, an international standards body that created the format in 1992. Designed to be universally adopted, it is the one and only file format for photographs that microstock agencies, printers and Web pages will all accept.
JPEG files are compressed, so they are relatively small in size. This allows for quick display on computers, phones and websites. But there is a significant cost: loss of data. The image is slightly degraded which can be visible on larger prints as “compression artifacts.”
The “lossy compression” of JPEG can be varied, to trade off between image quality and file size. For professional work, we should use the highest image quality setting, which is “12.” That’s right, we’re even better than Spinal Tap.
Put it up to Eleven, from Spinal Tap
Nigel Tufnel: The numbers all go to eleven. Look, right across the board, eleven, eleven, eleven and…
Marty DiBergi: Oh, I see. And most amps go up to ten?
Nigel Tufnel: Exactly.
Marty DiBergi: Does that mean It’s louder? Is it any louder?
Nigel Tufnel: Well, It’s one louder, isn’t it? It’s not ten. You see, most blokes, you know, will be playing at ten. You’re on ten here, all the way up, all the way up, all the way up, you’re on ten on your guitar. Where can you go from there? Where?
Marty DiBergi: I don’t know.
Nigel Tufnel: Nowhere. Exactly. What we do is, if we need that extra push over the cliff, you know what we do?
Marty DiBergi: Put it up to eleven.
Nigel Tufnel: Eleven. Exactly. One louder.
Marty DiBergi: Why don’t you just make ten louder and make ten be the top number and make that a little louder?
Nigel Tufnel: [pause] These go to eleven.
— Christopher Guest and Rob Reiner in This Is Spinal Tap, 1984.
Is Lossy Compression A Problem?
In most of our applications, no. If it’s good enough for stock agencies, it’s good enough for us. The compression algorhithms are designed to be barely perceptible to the eye. And for larger prints, companies can use special “up-sampling” software to intelligently guestimate the lost data.
JPEGs for Websites and Books
The only photo format that websites use is JPEG. The HTML standard has other image formats, such as GIF and PNG, but those are for graphics and are not suitable for photos. Raw files and TIFFs are not supported. The ePub standard for books uses the HTML standard, so the same applies there.
All the photos in this book are JPEGs.
Cameras can allow you to control the compression. A setting such as JPEG SMALL would make a small file so that you can save many images on one data card. For selling photos, you want the highest quality, which is often called JPEG FINE.
One thing you want to avoid is resaving a JPEG as a JPEG. Each save loses data, making the image look progressively worse. If you’re making adjustments in Photoshop, then do so once only. If you later want to make more changes, start with the original file if possible.
Printing professionals can avoid this problem by using a lossless format called TIFF.
TIFFs are generally lossless files, usually used for high-quality printing. Graphic designers working in print, and printing professionals use TIFFs, and all the photos in my coffee-table books are TIFFs. The artifacts introduced by JPEG compression are not present in a TIFF, unless the image was previously saved as a JPEG.
An abbreviation for Tagged Image File Format, TIFF is an industry-wide format now controlled by Adobe Systems. It is the oldest and least current format described here, being last updated in 1992.
TIFFs can use “lossless” compression so that there’s effectively no image degradation. Besides the image (which can optionally be stored as a JPEG), the format can also hold Photoshop files such as clipping paths and layers.
“…you are also welcome to upload TIFF’s. TIFF files are ultimately converted into a JPG file by our system.”
JPEG to TIFF
There’s no direct improvement in saving a JPEG as a TIFF. Whatever image quality and problems there were before will continue over. The quality won’t increase, just the file size.
For my coffee-table books, I send the printer the original untouched JPEGs. They convert the files to TIFFs and do all the Photoshop work, as they know what their printing machines require.
Printers convert JPEGs to TIFFs so they can tweak things in Photoshop without losing image quality, but that’s necessary for printers not photographers. If you want to do many changes in Photoshop, you should start with the best image quality possible, namely, raw files.
JPEG or RAW?
Raw and JPEG are file formats for photos. JPEG is a universal, industry-wide format accepted by all microstock agencies, printers, Web browsers, and anywhere else you’re likely to go. Raw, in contrast, is not accepted by those places.
Raw files are a group of formats that are proprietary to individual camera manufacturers. You’ll need special software to read raw files and you’ll have to convert them into JPEG files for microstock agencies and printers. So why would you need raw? For high-end Photoshop work. Raw files contain all the data from the camera, whereas JPEG files have lost some of that data by being compressed and standardized.
Raw files can be interesting, fun, and technical to work with. That’s fine as separate interest. But raw files are not necessary for — and will take time and focus away from — what this book is about: selling photos. So, unless you’re strong with Photoshop, stick with JPEG.
But perhaps you are strong with Photoshop. Then let’s learn more about RAW.