Study Three: Conversion of JPEGs and PICTs to GIF format

This study was made to test the difference between JPEG compressed images and PICT files made into GIFs for a black and white document (original size: 81/2 by 11 inches). It also compares the difference between the JPEG and GIF thumbnails. All thumbnail images are 147 x 150 pixels and all of the images were scanned at 72 ppi.

Can you see the difference between GIFs made from PICT files and GIFs made from JPEG files?

Can you see the difference between the GIF and JPEG thumbnails?


Bitmap Pict,
Saved as GIF
22 K


Pict converted to
Grayscale JPEG,
Maximum Quality
22 K

Seven files were made for this study:

Kind of File Resolution Mode Size Dimensions Legibility
Pict72 ppiBitmapped38 K7.625 x 7.806 inchesMostly legible
Pict72 ppiGrayscale302 K8.447 x 10.569 inchesMostly legible
JPEG72 ppi,
maximum quality
Grayscale302 K7.625 x 7.806 inchesMostly legible
GIF72 ppiBitmapped302 K8.447 x 10.569 inchesMostly legible
GIF
Thumbnail
Pict file, bitmapped72 ppi22 K
150 x 147 pixelsIllegible
GIF
Thumbnail
JPEG file,
grayscale
72 ppi22 K150 x 147 pixelsIllegible
JPEG
Thumbnail
JPEG file,
grayscale
72 ppi, max. quality22 K150 x 147 pixels Slightly legible

Findings


Back to the Beginning

Conclusion

Maia Jin, mjin@umich.edu, October 1995