[Coco] Master List

[Theodore Evans (Alex)]

On Mar 6, 2004, at 6:37 PM, KnudsenMJ at aol.com wrote:

> TIFF is a very inefficient, HUGE format, with no compression.  GIF is 
> best
> for black-and-white images, or 16 shades of gray.  On strictly 2-color 
> (black &
> white) text and line drawings, GIF is 10x better than anything else.

I agree about TIFF being an awful file format (for these purposes) , 
but PNG is at least as good as GIF in these cases.  Technically there 
are a couple options for compression with TIFF, but you rarely see 
these used and some programs which support TIFF do not support them.

> But scanned text, if in strict B&W, will be terribly broken up and 
> moth-eaten
> or acid-etched looking, and lines will fade in and out of drawings.  
> So to
> permit "aliasing" which preserves the shapes, it's best to scan in 16 
> shades of
> gray, and GIF that.  Under some conditions, JPEG may do better than 
> GIF,
> certainly for 256 shades of gray as would be used for photos.

If you set your thresholds properly B&W will work just fine for scanned 
text.  Of course if you use B&W rather than 16 levels of gray you are 
going to want to use a slightly higher resolution (though the 300 DPI 
previously mentioned should be more than adequate even for this).  I 
have never seen a case where an image with fewer than 64 levels of gray 
compressed better with JPEG without significant loss of quality.

-- 
Theodore (Alex) Evans | 2B v ~2B = ?