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TIFF and LibTiff Mail List Archive

Thread

2000.12.15 09:50 "Stripes in thumbnail", by Christian Bednarek
2000.12.17 22:12 "Re: Stripes in thumbnail", by peters
2000.12.18 05:57 "Re: Stripes in thumbnail", by Christian Bednarek
2000.12.17 23:41 "Re: Stripes in thumbnail", by Joris Van Damme
2000.12.18 00:02 "Re: Stripes in thumbnail", by Joris Van Damme
2000.12.18 14:30 "Re: Stripes in thumbnail", by Bob Friesenhahn
[...]

2000.12.17 22:12 "Re: Stripes in thumbnail", by peters

Hello :-)

I'm trying to create a (rgb-)thumbnail out of up to four single separated G4-TIFFs. But creating a thumbnail from these G4s ends up in a grayscale with vertical stripes. An example is here:

http://home.rhein-zeitung.de/cbednare/TIFF/

Can I do smth. about that?

Maybe you can even provide me with a snippet of code for composing four singe grayscale into a cmyk-tiff? (well... sitting in front of TIFF6.0 at the moment :)

Well,

what you need to do is some sort of descreening to avoid the moires you are getting,

and then convert the contone CMYKs to RGB and then create your profile.

This is quite a complicated area and you would have to investigate it yourself. There is lots of stuff in the literature and the internet about descreening.

just go to http://www.google.com and do a search for descreening

--
Peter Skarpetis
Serendipity Software Pty Ltd
67 Fitzroy Street
Surry Hills NSW 2010
Sydney Australia

Phone: +612 93321788     
Fax:   +612 93321766
email: peters@serendipity-software.com.au
WWW:   http://www.riponce.com