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From John Hewson <j...@jahewson.com>
Subject Re: How can I write JPEG2000 encoded images in PDF?
Date Fri, 01 Apr 2016 13:57:43 GMT
On 31 Mar 2016, at 14:34, Olaf Drümmer <olaflist@callassoftware.com> wrote:

>> On 31.03.2016, at 13:40, John Hewson <john@jahewson.com> wrote:
>> 
>>> 
>>> 2. What would be your suggestion for non-lossy compression for color images
>>> in PDF files? I know LZW is an answer, but the compression is much worst
>>> than JPEG2000.
>> 
>> First of all I'd check if a maximum-quality JPEG isn't good enough. It usually is.
If you really need lossless (and as you're archiving you might well do) then PNG is simple
and reliable. There are ways to losslessly optimise the colour palette to reduce file size
a bit. Also make sure you use the right colour space - a b&w raster is 1/3 the size of
an RGB one.
> 
> JPEG2000 also lets you do lossless compression.
> 
> PNG does not have anything to do with PDF.

I'm using PNG as a shorthand for Flate + Predictor which is the same compression that PNG
uses - though you're quite right that it's not actually a PNG file.

-- John

> Olaf
> 
> 
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