Chagall Reference  TIFF-Formats           12.5.93
==================================================

   If one chooses TIF as the extension of a file  
   name then a dialog box appears in which one can
   set important characteristics of the TIFF format.
   These determine in which order certain picture 
   information will be stored. This order varies
   depending on the computer, or more accurately, 
   on the type of microprocessor. If one works with  
   TIFF pictures only on Atari- or Apple-Macintosh 
   computers then one should stay with the pre-set
   'Motorola' format. If one exchanges TIFF-pictures 
   with MS-DOS-compatible PCs with Intel processors 
   it may be necessary to select the 'Intel' format. 

   However you should first experiment to see if the 
   corresponding PC application can perhaps understand
   the Motorola format. 'Invert' ensures that all
   colours are saved in an inverted form (low nibble 
   first), which is necessary for a few programs so that 
   they can read TIFF pictures correctly.

   'Other' determines which TIFF variation is to be 
   generated: As a rule the format that is shown is 
   the one that seems most sensible for the picture 
   that is to be saved.

   - 'CMYK (TIFF 6.0)' is applicable to colour pictures 
     and saves the image in a colour-separated form.
     For separation one uses separation curves in a 
     standardised format, which may be loaded directly
     from this dialog   (in preparation).

   - 'RGB TrueColor' is the standard format for colour 
     pictures using 24 bit colour depth.

   - '256 colours' leads to the creation of a picture 
     with a palette of 256 colours. This is a memory-
     saving process that suits some applications, but 
     is accompanied by some loss of picture quality as 
     a rule. If you only want to use the pictures for 
     presentations on the computer itself, then 256 
     colours are actually always enough. Also pictures 
     containing only a few colours, or perhaps many 
     colours with large colour jumps, will not lose 
     much quality so that the use of this memory-saving 
     format offers advantages.

   - 'Greytone' saves a halftone picture with 256 steps
     of grey.

   - 'REPRO ST' is a special format that is used to save 
     halftone images in the TIFF format in such a way
     that they can also be loaded by the Repro Studio
     program.

   - 'Save LUT' permits one to save the values in the 
     LUT-graph..\MENU\TOOLBOX\SPECIAL\LUT together with the picture. 
     Since some programs do not interpret this properly, 
     one should first test whether the program into which 
     the file is later to be imported can interpret the 
     curves correctly.
     
   Finally, 'Compression' determines whether the picture is 
   to be stored in an uncompressed form or with RLE- or LZW-
   compression.  Uncompressed pictures can be read by almost
   any TIFF-processing application, but in practice always 
   occupy more memory. LZW-compressed TIFF images are 
   noticeably more compact, and can also be read by most
   applications.
   The RLE compression is meant more for special cases in
   which this compression process can produce better results 
   than LZW.
