Someone recently asked me whether our software supports TIFF Group 6 compression. TIFF Group 6? WTF? I'm having a hard time finding information about TIFF Group 6 on the internet, let alone in the DotImage documentation. Can someone in these forums speak knowledgeably on TIFF Group 6? Can someone point me to an authoritative source?

Thanks.
 

Are you sure its tiff group 6?

You can use this dotimage function to get the compression used for an image.

We use tiff but only group 4.

[Visual Basic]
Dim comp As Integer = Convert.ToInt32(TiffDecoder.GetTiffTag(259, FileName, 0).Data)
Select Case comp
     Case 1          ' None
     Case 2          ' CCITT modified Huffman RLE
     Case 3          ' CCITT Group 3 fax encoding
     Case 4          ' CCITT Group 4 fax encoding
     Case 5          ' Lempel-Ziv & Welch (LZW)
     Case 6          ' 6.0 Old Style JPEG
     Case 7          ' JPEG DCT compression
     Case 32773  ' Macintosh RLE
     Case 32946  ' Deflate
End Select

Reagrds,
Graham.

That is what is at the heart of my question: is there such a thing as TIFF Group 6 compression? I've never heard of TIFF Group 6, but a customer recently asked one of our salesmen whether our software supports TIFF Group 6. I'm asking whether anyone has ever heard of TIFF Group 6, what they know about it, and whether they can point me to more info on it. Also, what is Group 5?

There are two major forms of CCITT compression, CCITT T.4 which is called Group 3 and CCITT T.6 which is called Group 4.

 

Maybe you're got some confusion around the terminology of CCITT T.6 with "group 6".  As far as I know, there is no group 6 compression.

---

Steve Hawley
Architect & Exception Handler
Atalasoft, Inc.

"CCITT T.4 which is called Group 3 and CCITT T.6 which is called Group 4 ... "

No wonder there is confusion. Thanks for your answer, Steve.