HP Super Jpeg

[Pages:2]HP Photosmart Digital Cameras

Technical Backgrounder

Super Jpeg

What is Super JPEG?

HP Super JPEG is HP's implementation of the JPEG specification that produces the highest quality image possible. It allows the advanced digital photographer to capture images suitable for large prints that contain no visible compression artifacts.

How does Super JPEG work?

Most digital cameras use the JPEG 4:2:0 or 4:2:2 compression setting when storing images. Both of these settings store the chrominance (color) information at a lower resolution than the luminance information, resulting in less color detail. HP's SuperJPEG uses the JPEG 4:4:4 setting, which stores color information and luminance information at the full resolution of the original image. This results in much better color accuracy. Second, Super JPEG uses minimal quantization. JPEG functions by calculating the discrete cosine transform of 8x8 blocks of data and then quantizing the coefficients. By minimizing quantization of the coefficients a Super JPEG will produce an image with no visible compression artifacts.

Do other cameras do anything like this?

No, some cameras output TIFFs which are larger, but give no visible quality improvement over Super-JPEG. They also do not contain all the digital picture information in EXIF tags which are contained in a JPEG file.

How do I access Super Jpeg on my HP Photosmart Camera

Not all HP Photosmart Cameras support Super Jpeg. If your camera does, it is accessed by selecting "custom" resolution and setting compression to 4-star "****" compression. Note, the camera remembers this setting when you turn it on and off,

Reviewers need to know that...

Given state of the art digital camera capture technology TIFF images will contain no more information than a Super JPEG. Image quality is usually limited not by

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compression, but by photon shot noise determined by characteristics of state of the art CCD sensors such as well depth and read noise. Super Jpeg images will be larger than typical "best" quality Jpeg images, but much smaller than TIFF images. Besides lower file size, another advantage of Super-JPEG is that the images can be viewed and edited by any application that accepts JPEG, unlike TIFF, which, while commonly supported, is not as ubiquitous as JPEG.

? Copyright 2005 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice and is provided "as is" without warranty of any kind. The warranties for HP products and services are set forth in the express warranty statements accompanying such products and services. Nothing herein should be construed as constituting an additional warranty. HP shall not be liable for technical or editorial errors or omissions contained herein.

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