QTR-Quadtone RIP

I have tried to print a colour chart with QTR. Of course the colour 
were far from matching.
Pity ! QTR could be a really great RIP if we could print colours as we 
could adjust each colour channel, even switch one or two off if we 
wanted to.

Is there a procedure to make it work ?
Thanks

Hi,

I'm not the expert around here, but I don't think so. QTR is a 
dedicated monochrome RIP. As an attempt for a workaround one could 
try to fiddle around with toners, but for QTR allows only two (of 
which apparently no-one ever uses the 2nd toner) and for full colour 
one would need at least three. 

Joost


--- In QuadtoneRIP@yahoogroups.com, "lours51" <sinwen@...> wrote:
>
> I have tried to print a colour chart with QTR. Of course the 
colour 
> were far from matching.
> Pity ! QTR could be a really great RIP if we could print colours 
as we 

> could adjust each colour channel, even switch one or two off if we 
> wanted to.
> 
> Is there a procedure to make it work ?
> Thanks
>

And, after rereading my reply: QTR has no clue what to do with RGB 
files 


--- In QuadtoneRIP@yahoogroups.com, "horstenj" <j.h.j.h@...> wrote:
>
> Hi,
> 
> I'm not the expert around here, but I don't think so. QTR is a 
> dedicated monochrome RIP. As an attempt for a workaround one could 
> try to fiddle around with toners, but for QTR allows only two (of 
> which apparently no-one ever uses the 2nd toner) and for full 
colour 
> one would need at least three. 
> 
> Joost
> 
> 
> --- In QuadtoneRIP@yahoogroups.com, "lours51" <sinwen@> wrote:
> >
> > I have tried to print a colour chart with QTR. Of course the 
> colour 
> > were far from matching.
> > Pity ! QTR could be a really great RIP if we could print colours 
> as we 
> > could adjust each colour channel, even switch one or two off if 
we 

> > wanted to.
> > 
> > Is there a procedure to make it work ?
> > Thanks
> >
>

horstenj wrote:
> And, after rereading my reply: QTR has no clue what to do with RGB 
> files 

Well it makes greyscale of it :-)

Your request for the 3 curves more or less implies a small 
color engine in QTR anyway. QTR could still be restricted to 
greyscale input only though. A kind of color engine would 
allow a more flexible softproof/preview on QTR too. Something 
that has been discussed before.


Met vriendelijke groeten,Ernst


|  Dinkla Grafische Techniek  |
|     www.pigment-print.com    |
|             ( unvollendet )            |

--- In QuadtoneRIP@yahoogroups.com, Ernst Dinkla <E.Dinkla@...> 
wrote:
>
> horstenj wrote:
> > And, after rereading my reply: QTR has no clue what to do with 
RGB 
> > files 
> 
> Well it makes greyscale of it :-)
> 
> Your request for the 3 curves more or less implies a small 
> color engine in QTR anyway. 

I assume you refer to my post in the other thread. Not sure if 
a "color engine" is right word here. I would regard it simply as an 
interpolation (for each gray tone) between three possible values iso 
two. Is that a "color engine"?


>QTR could still be restricted to 
> greyscale input only though. A kind of color engine would 
> allow a more flexible softproof/preview on QTR too. Something 
> that has been discussed before.
> 
> 
> Met vriendelijke groeten,Ernst
> 

I'll keep it in Englisch, but by the way, we're practically 
neighbours. I live in Eindhoven as well. I you like we could meet 
one another somewhere sometime.

Joost

> |  Dinkla Grafische Techniek  |
> |     www.pigment-print.com    |
> |             ( unvollendet )            |
>

Joost, je schrijft:


> I assume you refer to my post in the other thread. Not sure if 
> a "color engine" is right word here. I would regard it simply as an 
> interpolation (for each gray tone) between three possible values iso 
> two. Is that a "color engine"?


When you make gradual steps between two ink mixes like it is
already done with the slider of QTR there isn't much needed. A
third one added will increase the complexity as it is no
longer a one dimensional path and I expect that you can't
control that without a kind of color engine. In that case it
might be easier to go for something like LittleCMS as it also
could cooperate better with the (semi) ICC profile creation
of QTR. This would allow interaction between sliders and a
preview window too. Of course this comes close to the Advanced 
B&W menus of the latest inkjet printers. The last lack the 
transparent calibration of QTR though.


Met vriendelijke groeten,  Ernst


|  Dinkla Grafische Techniek  |
|     www.pigment-print.com    |
|             ( unvollendet )            |

--- In QuadtoneRIP@yahoogroups.com, Ernst Dinkla <E.Dinkla@...> wrote:
Ernst,

Perhaps I do not really get it, but:

> When you make gradual steps between two ink mixes like it is
> already done with the slider of QTR there isn't much needed. A
> third one added will increase the complexity as it is no
> longer a one dimensional path.

That's obvious

> and I expect that you can't
> control that without a kind of color engine. 

But why not simply have three sliders, one for each curve, giving the 
relative weight of each curve, just like the channel mixer in 
Photoshop? (would be nice though if the weights automically be 
balanced to 100%, a feature I miss in PS). The result would be just 
the weighted average of the three curves. Just like the current 
slider is the weighted average between two curves. The mathematics of 
this 3 curve averaging is trivial. What should this 
color engine do more than that? Do I miss something? 

Joost

--- In QuadtoneRIP@yahoogroups.com, "Joost Horsten" <j.h.j.h@...> wrote:

> But why not simply have three sliders, one for each curve, giving the 
> relative weight of each curve, just like the channel mixer in 
> Photoshop? (would be nice though if the weights automically be 
> balanced to 100%, a feature I miss in PS). The result would be just 
> the weighted average of the three curves. Just like the current 
> slider is the weighted average between two curves. The mathematics of 
> this 3 curve averaging is trivial. What should this 
> color engine do more than that? Do I miss something? 

Now I have given this some more thought I think I understand what you 
mean. I think we have two different objectives, yours being more 
advanced than mine.

My approach is that of a painter, having a choice of pigments (curves), 
putting some together in certain quantities and looks to end result. If 
that is not right yet, you change the quantities and try again. 

My interpretation of your approach is that you want to define a colour 
point in advance and have the relative contributions of the primes be 
determined by the system.

In my approach, the simple slider approach would suffice (although now 
I think it over, the number of sliders is not fundamentally limited to 
three as I stated earlier). In your approach (as interprete it), which 
is much more sophisticated, one needs a color engine indeed.

I'd love use to your color-engine approach, but for my now my desires 
are more modest ;-). Just a set of sliders and experimenting with the 
result would already be great.

To give some idea how I think to bring some system in this experimental 
approach. First mix two of the "primaries" to get the hue you desire, 
than add as a third curve a neutral curve to control the saturation of 
the mix. This is more or less how I mix my paints & inks in one of my 
other lifes as painter/printmaker.  

Do we converge in our thinking? Or do I still miss the point?

Joost