QTR-Quadtone RIP

Thanks Roy.  I didn't know what the syntax was for the curves  
functions.  I have K7 inks loaded in my 2400 so I'll give this  
approach a try.

Carl

On Jan 16, 2007, at 7:07 PM, Roy Harrington wrote:

> Hi Carl,
>
> It's easy to do on the Mac, too.     Just use:
> CURVE_K=k7_black.acv
> CURVE_LM=k7_ltmagenta.acv
> etc...
>
> Howard's idea is an interesting possibility.   You could design the
> basic curve
> shapes this way and then linearize the result.   The potential
> difficulty would be
> that you get some flat spots or extra wiggles in the density curve.
> Just because
> the look smooth doesn't mean the sum on the curves with different inks
> would
> also look that smooth.  The linearize can fix only so much.   In the
> specific example
> it probably would work well since they are designed from existing
> "good" profiles.
>
> Since the K7 inks are so close in density you can have the very large
> overlaps
> -- ie. 5 inks instead of just 3.   There is also some benefit in the 
> 2880dpi because its
> only one dotsize.   At 1440 there will be 2 or 3 dotsizes used which
> results in more
> transitions.
>
> For anyone wanting to customize their own K7 ink profiles a very nice
> approach is
> to take advantage of the piezo k7 profiles and then build ICC profiles
> on top of
> them.  This way you get full color management from screen to print  
> with
> softproofing
> as well.
>
> Roy
>
> On Tuesday, January 16, 2007, at 03:14  PM, Carl Schofield wrote:
>
>> I assume this is only for the PC version or is there a way to use
>> the .acv curves with the Mac version of QTR?
>>
>> Carl
>>
>> On Jan 16, 2007, at 5:44 PM, Howard Shaw wrote:
>>
>>> Joost
>>>
>>> If you have a look at the Cone-made k7 curves (the 2880dpi ones)  
>>> they
>>> are differently constructed to the type of curves that qtr makes.
>>>
>>> I've made a web page showing the difference and also how the Load
>>> curves
>>> facility in qtr can be used to emulate the type of curves  
>>> produced by
>>> Cone's proprietary method.
>>>
>>> http://www.howardshaw.org/docs/k7-qtr/k7curves.htm
>>>
>>> The main difference is that the normal qtr curve creation method  
>>> using
>>> density boundaries usually only allows 3 inks to overlap at a time
>>> whereas the Cone curves have upto 5 overlapping inks. On the basis
>>> that
>>> the more jets firing the better this should lead to a smoother  
>>> print.
>>>
>>> Note that I do not have the K7 inks so this is a technical exercise
>>> only.
>>>
>>> Howard
>>>
>>> Joost Horsten wrote:
>>>> --- In QuadtoneRIP@yahoogroups.com, "Scott Schroeder"  
>>>> <schrochem@...>
>>>> wrote:
>>>>
>>>>> I didn't mean you couldn't make curves. I was just saying you  
>>>>> can't
>>>>> make curves that have the nice transitions and crossovers that are
>>>> in
>>>>> the supplied curves.
>>>>> This message will explain it better:
>>>>> http://tech.groups.yahoo.com/group/QuadtoneRIP/message/1165
>>>>
>>>> Thanks Scott, that explains your remarks indeed. But for my
>>>> information: does it make in practice REALLY any difference whether
>>>> you use these original PiezoBW curves in stead of making your own
>>>> curves with QTR? Since I'm printing on 2880 dpi with QTR/2100/UT3D
>>>> I've a hard time to find any grain in my prints. So, imho on that
>>>> aspect I expect there is little left to improve by going to 7 inks.
>>>> But even if so, do the details of the curve then still make a
>>>> difference on top of that? Or does the claimed smoothness of the  
>>>> NK7
>>>> inks ONLY appear with the custom PiezoBW curves?
>>>>
>>>>  Joost
>>>>