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Real World Example

PHASE IV-B: Save As... File Formats


JPEG:

Super compressed file format. Joint Photographic Experts Group wrote the compression standard for the JPEG file format.

In the previous section, even the Improved image still has a mushy look.

The image was compressed at Quality: 3 Medium. The resulting image has the characteristic JPEG compression artifact. JPG Quality 3
A Photoshop JPEG Quality: 10 High would eliminate the mushy look at the cost of increased file size.

Though the settings are numeric, they are not absolute. The image size and characteristics interact with the JPEG compression process. Testing is a must with JPEG.


Photoshop JPEG Settings: A Great Guide.

JPEG is universal but the settings are not. Photoshop descriptions for the settings are excellent guides.

  • 0 to 2 are LOW, avoid if possible.
  • 3 to 5 are MEDIUM, lot of web images requires this.
  • 6 to 7 are HIGH, better settings for better quality.
  • 8 to 10 are MAXIMUM, best settings to use.

Paint Shop Pro™ is a small graphics application that I use often. Its JPG setting method is gruesome by comparison. Paint Shop Pro's JPEG settings range from 1 to 99 with no clue as to image quality levels.

I use Progressive set to Scan 3 for web images. This allows the image to build in focus from soft, medium, to sharp. The Scan 5 setting looks more like a down-loading error. Test it for yourself.


CompuServe GIF:

Graphic Interchange Format is great for saving graphic files. GIF files are a lot easier to handle in Paint Shop Pro. Especially the GIF transparent background color option.

The sample Photoshop menu above has a torn edge look. This would not be possible without the GIF transparent background color option.

A major draw back to the GIF format is its seriously limited color range. It only allows for 256 colors. Ordinarily, photographic images do not survive such a radical color palette reduction.

I have seen some pictures reduced to a GIF and they were quite passable. The process can require manual color palette manipulation. Try it, you will learn a lot about working with palettes.

GIF animations using photo realistic images will demand photo images to be reduced to 256 colors.


JPEG: Staggering Power

12KB: JPEG set to Medium 5. Stevie saved as JPG 13KB: GIF file size bigger. Stevie saved as GIF
  • Full color JPG file size is 12 KB.
  • The 256 color GIF file size is 13 KB.
  • The LZW compressed TIFF file size is 115 KB.
  • The uncompressed TIFF file size is 232 KB.
This is only one example. An image with differing characteristics will yield different file size relationships.


TIFF With LZW Compression

The TIFF file format is excellent for archiving or transferring photographic images. PC's and Mac's share TIFF files easily. LZW is a no-loss alga rhythm so nothing is sacrificed for file size reduction.

Do not use JPEG for archive purposes. Regardless of the setting, JPG images suffer loss in quality. Some of the image data is lost and compression artifact adds garbage to the image. Photoshop Filters work best on high quality images.


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