[comp.sys.next] Problem with NeXT tiff's on PC's

jim@ljkiraly.lerc.nasa.gov (L J "Jim" Kiraly) (05/28/91)

I need to transfer some graphics as tiff files for use on a PC (unfortunately
the unenlightened are still using PC's).  All I get on the PC is a black
rectangle or a series of bars when I try to display the transferred tiff
files.  I have checked that the tiff files were properly sent by sending
them back to my NeXT and comparing the originals.  None of the tiffs used
any of the tiffutil compression schemes.  I presume that the NeXT uses some
different aspects of the tiff standards than is customary for PC-Windows
based tiff readers (specifically I want to get them into PageMaker).  Has
anyone else experienced this problem?  I'm not ambitious enough to dig 
through the tiff specifications and was hoping someone else has already
solved this problem.

Thanks-

--
___________________________________________________________________________
  Jim Kiraly  - jim@ljkiraly.lerc.nasa.gov  -  NASA Lewis Research Center
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aozer@next.com (Ali Ozer) (05/28/91)

In article <1991May27.172417.17273@eagle.lerc.nasa.gov> L J "Jim" Kiraly writes:
>I need to transfer some graphics as tiff files for use on a PC ...
>All I get on the PC is a black rectangle or a series of bars when I try
>to display the transferred tiff files. ...

One likely problem is transparency; TIFF images created by NeXTstep can
include transparency, which TIFF readers on other machines might not
understand or interpret correctly.  To remove transparency, you can use Icon
and save the images with the "No Alpha" option.

Other possible problems include:

- Images are 2 or 4 bits (per sample) deep. (If you created the TIFFs on
  a monochrome NeXT the former is likely.) Some simple minded TIFF readers
  might not understand these formats; try saving the images at 8 bits
  per sample (Using the "8 bit" option in Icon for monochrome images or
  "24 bit" option for color ones.)

- Images don't have color lookup tables. NeXTstep creates TIFFs without
  color lookup tables; again, some TIFF readers might not be able to deal with
  this.  You might have to find some other TIFF reader which can read 
  the images and write them out with color lookup tables (after determining
  what the best palette is, of course).

Good luck...

Ali, Ali_Ozer@NeXT.com