QTR-Quadtone RIP

Hi Ernst,

I've been out of town and touch for a while so I'm just getting to things.

Like Greg said, the linearization numbers are always assumed evenly spaced
for however number there are.  The tricky part comes when you make the
targets.
With 8 bits (256 values) files and K in percents (100 values) roundoff
errors and
uneven steps are likely.  16 bit files are the best solution but even
that is tricky
because you can't enter 16 values.  A posterized 16 bit gradient will
give correct
values, or starting with 33 even 8 bits values (0-160) and then
stretching it out
in 16 bit mode.  Once you have a good evenly spaced 16 bit file its OK
to convert
to 8 bit - the spacing will still be good.

Finally there's the reading of the target.  I think you get a lot of
benefit from averaging
multiple patches (more important than more steps).  MeasureTool with a reference
file works great for this because the ref file tells all the gray
values.  (Note: use
decimal values for gray if needed -- e.g. 0 3.33 6.67 10 13.33 ...).
Without a ref file
QTR makes a best guess based on how many patches total there are -- works
well for most cases but you may be able to stump it.

Roy

On Thu, Jun 7, 2012 at 11:21 AM, Ernst Dinkla
<e.dinkla@...> wrote:
> On 06/07/2012 07:47 PM, John Labovitz wrote:
>
>> Given that the QTR tools don't seem to need any configuration to
>> indicate the particular patches (they're just read from the CGATS file,
>> as you know), I'd reckon that there's no assumption being made as to the
>> specific intervals between patches. Hence, having arbitrary patches as
>> you're describing will probably work.
>>
>> --John
>
> John,
>
> Thank you, gives me confidence enough to go that much easier route.
>
>
> --
> Met vriendelijke groet, Ernst
>
> Dinkla Grafische Techniek
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-- 
Roy Harrington
roy@...
www.harrington.com