Understanding File Formats

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I tend to change the file format of my photos frequently--usually from JPEG to TIFF or JPEG to Adobe Photoshop's PSD format. Why would I do that? Usually, to preserve image quality.

Every time you edit and then resave an image in JPEG format, for example, it loses a little quality (depending upon how much compression is used in the resaving). A few file formats, though, like TIFF and PSD, don't inflict that kind of punishment. So if I need to edit a photo that was originally shot in JPEG format, I typically save it in the TIFF format before I start editing to lock in the image quality, as they say in the sandwich bag industry.

That's not the only reason I change file formats. These days, I take most of my photos in my camera's RAW format. But RAW files are huge and most people can't view them on their computer. So in order to share photos with friends, family, editors, or anyone else who needs a copy, I need to save the final, edited versions as JPEGs.

As you can see, there are some good reasons to occasionally change formats. This week let's talk about what everyone should know about how, when, and when to change a photo's file format.

File Format Myth

Before we go too far, let me dispel a popular misconception. A lot of folks have heard about how saving JPEG photos can affect the image quality. Some people take that idea too far and worry that viewing a JPEG can be hazardous as well.

Not true.

Just looking at a JPEG file doesn't affect its image quality. You can open the file in a photo editor, view it, and close it again without affecting quality--just don't make any changes and click the Save button. If you don't plan to edit an image, you can safely leave it in JPEG format forever and the image quality will never degrade.

Five Reasons to Change File Formats

There are many reasons to occasionally need to fiddle with file formats. Here are five of the most common:

You want to edit a photo. If you just adjust the contrast and crop the image, any image quality loss will be almost imperceptible when you resave the photo in JPEG. But if you plan to make a number of changes to the photo and expect to save your changes several times, then you might want to convert the file to TIFF or PSD format first. Make all your changes in that lossless format, and then convert the final image back to JPEG at the end.

You want to save space. If you have your camera configured to record your photos in RAW format, for example, you might want to save the final, edited versions of those images in JPEG to save hard disk space.

You need to share photos or post them on the Web. I love my camera's RAW format, but it's not easy to share. Edit your RAW photos, and then save them as JPEGs so others can enjoy them.

You need to convert an image from an unusual format. Every once in a while someone will send me a photo in an exotic file format like PCX, bitmap, or TGA. Thank goodness Photoshop lets me save that file as a JPEG.

You want to can keep your edits intact between editing sessions. If you use Adobe Photoshop Elements, for example, you can save your photos in the PSD format to maintain individual layers. That way you can fine-tune your photo without starting over from scratch in every editing session.

Changing File Formats

Saving a photo in a different file format is simple. As usual, I'll demonstrate with Adobe Photoshop Elements, but the procedure is almost exactly the same no matter what program you use.

Open the photo in the image editor and then choose File, Save As from the main menu. In the Format drop-down menu, choose the file format you need. You'll see options for all the common formats, including TIFF and JPEG. Click OK to save the file.

You will find that some formats have extra options you need to configure before the save is completed. For a JPEG file, for example, you need to specify how much compression to use. The more compression, the smaller the file will be, but the lower the visual quality. My advice is to always use the maximum quality (12 in Photoshop Elements).

After saving the file, you'll have two copies: the original file, such as myfile.jpg, for instance, and one called myfile.tif. You can keep both copies or delete the older one, depending upon your needs.

Of course, it can be difficult to tell the two files apart on the Windows desktop if your system is set to hide file extensions. When in doubt, right-click the file and choose Properties from the menu. Be sure to verify the extension before deleting a file.

To more easily distinguish between files with the same name but different file formats, you can make file extensions visible in Windows. To do that in Windows Vista, open a folder and choose Organize, Search and Folder Options; in Windows XP, choose Tools, Folder Options. Click the View tab and then uncheck "Hide extensions for known file types."

Hot Pic of the Week

Get published, get famous! Each week, we select our favorite reader-submitted photo based on creativity, originality, and technique. Every month, the best of the weekly winners gets a prize valued at between $15 and $50.

Here's how to enter: Send us your photograph in JPEG format, at a resolution no higher than 640 by 480 pixels. Entries at higher resolutions will be immediately disqualified. If necessary, use an image editing program to reduce the file size of your image before e-mailing it to us. Include the title of your photo along with a short description and how you photographed it. Don't forget to send your name, e-mail address, and postal address. Before entering, please read the full description of the contest rules and regulations.

This week's Hot Pic: "The Strawberry," by Diana Orlando, Edison, New Jersey

Diana writes: "I watched as my granddaughter consumed one strawberry after another, and I saw a great opportunity for a neat picture. ... The strawberry was huge and so red that I decided to focus on it, so I tweaked the colors in Adobe Photoshop."

This Week's Runner-Up: "Lazy Afternoon," by Wayne Boardman, York, Maine

Wayne writes: "This herring gull seemed content to spend the afternoon perched on a dory moored in a York, Maine tidal inlet. I took the photo with my new Canon S5 IS and then just cropped and sharpened it and applied a black-and-white filter."

See all the Hot Pic of the Week photos online.

Have a digital photo question? Send me your comments, questions, and suggestions about the newsletter itself. And be sure to sign up to have the Digital Focus Newsletter e-mailed to you each week.

This story, "Understanding File Formats" was originally published by PCWorld.

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