Monochrome group 4 TIFFs exported from ArcMap 9.x are displayed as a reversed or negative image or are 'chunky' or 'blocky'.
Some TIFF viewers do not read this format correctly, and reverse black and white values, rendering a negative image. Microsoft (MS) Paint is one example of a viewer that renders CCITT Group 4 TIFFs incorrectly. Both Adobe Photoshop and ArcMap display the values correctly.
There has also been a significant change in the way ArcMap converts map images from color to 1-bit on export.
At 8.x, the color map image was automatically dithered, giving a false gray effect by selectively filling pixels according to the brightness of the original color and surrounding pixels.
At 9.x, dithering only occurs in 8-bit exports; 1-bit exports will not dither. The 9.x exporters create a pure 1-bit representation based on a user-defined mask color or threshold.
ImageMagick has not been tested by ESRI nor does ESRI support the application.
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