QTR-Quadtone RIP

Roy Harrington wrote:
> Hi Ernst,
> 
> I don't remember being vague about QTR.  QTR resamples all input files
> to 720x720 pixels.
> Then dithering is done to whatever dpi you've selected -- mostly
> 2880x1440 or 1440x720.
> A couple printers also have 1440x1440.
> 
> The resampling to 720x720 is done by the OS on the Mac so I'm not sure
> of the algorithm.
> On the PC it's a bi-linear algorithm -- basically two linear
> interpolations -- horizontal then
> vertical.  As far as I know all the Epson drivers do either 360x360 or
> 720x720 resampling.
> In general the smaller printers tend to do 720x720 and the larger ones
> do 360x360.  If the
> driver has a Finest Detail switch that gives the user a choice between
> these resamplings.

Roy, with all respect, I have asked questions about its 
native resolution before and never got an answer as detailed 
as you describe it here. That may have been some years ago 
but I tend to have a good memory for subjects like the one 
discussed here. Never too late though :-) Thank you.

Not so long ago a similar discussion happened on one of the 
other list where the observation was made that smaller 
prints of the same image data tend to have more density than 
larger ones. I actually think it is a shift in contrast and 
the result of aliasing. It is content related.


-- 
Met vriendelijke groeten,  Ernst


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