QTR-Quadtone RIP

Joost Horsten wrote:
> --- In QuadtoneRIP@yahoogroups.com, Ernst Dinkla <E.Dinkla@...> wrote:
> 
>> I wonder whether it is possible to make just one general 
>> greyscale profile per paper with your application based on 
>> averaging 3 or 4 target measurements, each target made with a 
>> hue at the boundaries of the gamut one uses in B&W printing. 
>> Choices made with the ABW driver but when your QTR gets the 
>> same flexibility (sliders etc) it would work there too. I'm 
>> actually thinking of the HP Z3100 ABW driver. That 
>> averaged-general profile represents the average luminance 
>> scale of that small gamut used. It will not work for soft 
>> proofing color but I think the preview/softproof of the ABW 
>> drivers will be sufficient for hue selection. The P2P 
>> conversion can be done before the image is brought to the ABW 
>> driver/preview if the  ABW viewer isn't ICC profile 
>> compatible. My goal is to reduce the quantity of profiles as 
>> just one per paper and keep the flexibility of the ABW drivers 
>> in hue choice.
>>
>> Do you foresee visible shifts in the luminance range with the 
>> different hue choices even when that gamut is limited ?  Of 
>> course much depends on right averaging within that small gamut 
>> space.
> 
> Ernst,
> 
> I've too little insight yet to agree or disagree. But I have trouble 
> understanding how just one profile could cope with differences in the 
> inks for the different tones. A profile is not unique to a paper but 
> different for each paper-ink set combination. And in the sitation at 
> hand one needs three different ink sets (warm, cool, selenium). My 
> feeling is that your proposal would only work if e.g. the cool inks 
> would behave exactly identical to the warm and selenium inks. And for 
> the UT3D inkset there even is no LK selenium ink.
> 
> Do I miss something?
> 
> Joost

In color profiling we expect one printer profile to handle all 
kinds of images (even B&W) in a far bigger gamut. In this case 
it is a smaller gamut and it doesn't have to handle color just 
luminance. The only difference is that we exchange one hue for 
another to some degree and never extreme. Before the profile 
creation of QTR was made we used generic matte and gloss 
profiles, what I propose is a least customised to the 
individual paper, ink and printer etc used.

Met vriendelijke groeten,Ernst


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