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As usage of the Internet has grown, I've also seen an increased usage of JPEG files in areas where they don't belong. In this article I'll explain how JPEG files get small file sizes and the quality loss that this causes. I'll also go over the correct file formats to use in most circumstances and even the areas where JPEG is the correct format.
I've ask many users over the years why they are using JPEG files and I've always gotten one of two answers. First, JPEG files are small and the users like small. Second, everyone can view JPEG files. Read those answers again and you won't see any mention of quality. So if you are creating a file for a customer, you don't mind if the quality is ruined by the file format you've chosen?
When working with bitmap files, the sizes can become very large. This is because of the huge number of pixels involved to create a lifelike image. Each of those pixels must be described as one of 16.7 million colors. When you consider than an image suitable of printing can have over a million separate pixels, it is easy to see why the files grow so large.
To combat the large file sizes, various compression schemes have been developed to store all that data in less space. The majority of compression schemes are lossless. This means that even though they make the files smaller, no data is lost. Opening a file you had saved previously will give you the exact same data.
JPEG is a lossy format. This means that as files are saved, data is discarded so that the file can be compressed to even smaller sizes. Most software allows you to choose a level of compression. The smaller the file, the more data will be permanently lost. If you later open a JPEG file, make changes and save again, even more data is lost. So the file will only get worse over time.
Recently I was doing artwork for a charity motorcycle ride. On the advertising, each of the sponsors logos was featured. So I had to do something that I'm sure many of you have done hundreds of times. I had to contact each sponsor and get their logo. Many of them sent JPEG files because they felt it would be the easiest format for me to use. And I'm sure some of them didn't quite realize what a horrible format JPEG is for printing artwork.
The title sponsor of the event was the Phoenix Coyotes hockey team. Their logo is shown at right. Note that this logo was received in a vector format and therefore the quality is the highest possible at any given size.
While I did eventually get the correct logo that is shown at right, the original file I was sent is shown below left.
I'm sure many of you are now looking carefully at these two logos and trying to see what is so awful about the second one. First, it is a bitmap and will only look good at certain sizes. But that isn't the worst problem. For the most part, there are six colors in this logo and they are very well defined areas. If we zoom in on the JPEG, we can see the artifacts of the lossy compression. An example of this is shown below right.
Look carefully at the image at right and you will see splotchiness in areas that should be solid color. And when you realize that this particular file was saved as a very high quality JPEG with minimal compression then you'll see that things can only get worse when you use a higher level of compression.
The correct file format is highly dependent on the artwork being used. In this case the logo was later supplied as an EPS file which is a vector based format. This means the file can easily be scaled to any size while retaining perfect quality. Other formats that would have worked just as well would include CorelDRAW (CDR) or Adobe Illustrator (AI).
For photographic images, TIF is the most widely used format and no quality is lost in compressed files. No, the files won't be as small as JPEG files. But our goal is to get the best quality on output and not the smallest files. While GIF is almost as bad as JPEG for printing files, it would have been superior for the logo we've discussed.
Some users will think that opening a JPEG file and resaving a file as TIF will solve the problem. It won't. The quality will not get any worse by doing this, but it won't suddenly bring back the data that had already been lost by saving to JPEG.
If there weren't places where JPEG was appropriate, it wouldn't have been created. So now that I've slapped your wrists, let's talk about the places where it should be used.
The most obvious place for JPEG files is on the Web. If you have a photographic image that needs to be displayed on a Web page then JPEG is the correct format. Similarly, if you need to send a sample piece of artwork via e-mail then JPEG is a good choice. But you should make it very clear to the recipient that the sample is for viewing only. Should the recipient need to print the image, supply them with a more appropriate file even if it takes much longer to e-mail.
And finally, JPEGs are acceptable for digital cameras. Most cameras can save files in an uncompressed format, but this typically limits the numbers of photos on a memory card to one or two. Until cameras come with a better storage medium, use the highest quality JPEG format. Yes, the pictures will suffer a bit. Just make sure to resave them as TIF before you perform any edits.
If I've saved only one of you from ruining artwork, I'll have done my job. Hopefully many more of you will turn your back on the evil JPEG file format and begin to use something more appropriate. And if you can educate your clients to supply you with better files, we'll all end up with better quality artwork. Working with photographs produces big files. Get used to it. And if you are worried about filling up your hard drive, buy a bigger one. 100+ gigabyte drives are under $200 and they will hold millions of photos. That is a small price to pay for higher quality!
Do you now understand why JPEG isn't the best format to use in many circumstances? Will this article help you to increase the quality of graphics you produce? If so, we would appreciate a little thank you in the form of a donation. Just click the button below and enter the amount appropriate to the value you've gained from improving your graphic's quality.
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CorelDRAW X6 Font List · CorelDRAW X5 Font List · CorelDRAW X4 Font List · The Terms of Adobe Photoshop and Corel PHOTO-PAINT · CorelDRAW X3 Font List · Cropping and Rotating Files in Corel PHOTO-PAINT · The Magic of Color Styles · CorelDRAW's Find and Replace Wizard · Shorten Your Design Time with Templates · CorelDRAW's Multi-Faceted Eyedropper Tool · CorelDRAW and Special Characters · The Easy Way to Create Calendars in CorelDRAW · The Wide World of Labels in CorelDRAW · Including Variable Data with Print Merge · Resaving, Resizing & Resampling Files in Corel PHOTO-PAINT · Creating Your Own Fonts in CorelDRAW · The Evils of Using JPEG Files · Speeding Up CorelDRAW 11 and Windows XP · Symbols and Imposition · The Easiest Way to Recreate Logos · A Few Guidelines to Follow · Square Corners Can Be Sticky -- Rounding Corners in CorelDRAW · Creating Complex Shapes Easily with CorelDRAW · Identifying the Mystery Font · Two Ways to Create a Split Front Design · Last Word in Font Management · Calibrating Your Printed Colors with a Color Chart · Graphics Computing in 2001 · Hottest R.A.V.E. In Town · Get the Red Out of Eyes · Secrets of Color Management · Dressing Up Your PDF Files · How Adobe Acrobat Can Make Life Simpler · Why You Want PDF in Your Workflow · Converting a Scanned Logo to Vector in CorelDRAW · Designing 360 Degrees · Customizing Your Interface in CorelDRAW 8.0 · Fitting Text to a Path · Creating Cool Graphs Without a Spreadsheet · From CorelDRAW to Macromedia Flash, A Simple Example · Getting Rid of That Darned White Box · Converting a Bitmap Logo to Vector in CorelDRAW · Finding Clipart with ROMCAT
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