Legacy ImageMagick Discussions Archive

I have a single page color tif that I need to convert to Group4 fit. When doing so, the image is compressed but using RLE instead of Group4. Same with Group3. It seems that the conversion routine defaults to RLE in both cases. Any thoughts?

Try adding this to the convert command just before the output image name:
-compress Group4

Pete

I tried

convert -compress group4 colortif1.tif colortif2.tif

and

convert colortif1.tif -compress group4 colortif2.tif

in both cases colortif2.tif shows RLE compression.

I think he meant +compress

From the documents on compress:

"Specify +compress to store the binary image in an uncompressed format. The default is the compression type of the specified image file."

Try this:

• convert colortif1.tif -monochrome -compress group4 colortif2.tif

If that fails, its possible your TIFF delegate library does not have CCITT support built-in.

the -monochrome worked, but it converted to black and white. My main goal here is to convert the color tif to a Group4 or Group3 tif and retain the colors. Doing:

convert tif1.tif -compress group4 tif2.tif

converts the tif to RLE compression but it does retain the colors.

Doing:

convert tif1.tif -monochrome -compress group4 tif2.tif

converts the tif to Group4 compression but it does not retain the colors.

Is it possible to convert a color tif to Group4 or Group3 and retain the colors?

Sorry to beat this horse, but we have a customer that says that they must have these images in color and they must be converted to Group4. Thanks for any help.

Group3 and Group4 are bitonal:

A tag-based file format for storing and interchanging raster images; in this subtype, TIFF wraps a bitmap compressed using ITU_G4 (ITU-T T.6. Facsimile Coding Schemes and Coding Control Functions for Group 4 Facsimile Apparatus), and is thus limited to bitonal imaging, suitable for the reproduction of typographic or line-art originals.

and

Group 4 compression is a method for compressing monochrome bitmaps that is used by fax machines, and is also available as on of the compression options in TIFF file format.