Art 003 | Assignment 3

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Art 003 - Assignment 3

Image 2: JPG File

Have you ever seen so many people mesmorized by a large flame? This picture was taken right after Andrew (foreground) threw an entire shopping bag of leaves and small twigs (bag included) into the fire. The picture is from my friend Sean's surprise birthday party in January. It was originally a 3.3 megapixel image taken with a Sony CD Mavica digital camera. By default, the digital camera saved the image as a .jpg, or JPEG, file. The image was too large for a web download, so I placed it in Adobe Photoshop and reduced the image size to only 700 x 525 pixels. I also reduced the JPEG quality when saving the file. I compared different JPEG image qualities -- 25%, 50%, 60%. 75%, and 100% -- to see which would produce the best image for the smallest total file size. In all the quality levels I tried, image quality lower than 75% showed a noticable pixelation in the image -- obviously, the lower the image quality, the more evident the pixelation was. However, when compared side-by-side in the 4 UP view, the 75% and 100% images looked identical to my naked eye. As the 75% quality version was nearly half the file size as the 100% JPEG quality image, I opted for the lower file size, confident that I was not trading off too much quality in the process. Despite the camera's initial desire to save the image as a .jpg file, once in Photoshop I could have rendered the image to a different file type, like .gif. However, I chose to stay with .jpg because that format usually provides optimal file quality for photographs at the smallest size. True, a .gif version of this photo would produce a small file size, but the tradeoff would be noticable pixelation and a degredation in quality. JPEG files can display a wide array of colors and at even lower quality levels than the 75% quality I used above, such as 20 or 30%, the JPEG format's ability to provide over 256 colors still produces a fine looking image, even when enlarged to sizes like 700 x 525 pixels -- something nearly impossible for a .gif version of a photograph to achieve. This is because of the format's compression algorithm, the Discrete Cosine Transform, which takes brightness and color into consideration when compressing the image. This is not useful for abrupt color changes, such as the color of the flame in the photo, but overall the JPEG format provides the best optimization for the image. Note that the image on the index page for this project was also saved as a JPEG. It includes text and a blurring technique, both added in Photoshop, which create an added effect that would look poor in another lesser format, like a .gif.
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