Digital BW, The Print

In a message dated 5/5/02 3:15:36 PM, dd-b@... writes:

>> >If I wanted to just lay down the cyan ink. How could I do it
>>  
>> RGB file with a large rectangle filled with the RGB value: 0, 255, 255.
>
>This is not a practical question; just a bit of niggling detail
>curiousity.  Do you know through either driver analysis or microscopic
>evaluation of the printed results that this puts down *only* cyan ink
>in an absolute sense?  Or do you simply believe, as I do, that in
>printing a large area of pure cyan, the driver has *gotta* use mostly
>cyan ink?  
>
>In terms of purging, in particular, there's no meaningful difference
>between the two alternatives I mention.  But if you're using it to
>measure a maximum density for a quadtone ink, for example, it may
>matter, perhaps. 

There are no direct controls with an RGB driver... often the only way to know 
what is really being printed for a given color is to have all the other heads 
be clogged. I was once at an Epson convention booth when the black in a p
articular model of Epson stopped printing entirely. What caught the attention 
of the Epson employee I was talking with was not the clog (ink is free and 
replacement printers easily available... kind of a printers ShangraLa) but 
the fact that there was a ghost of undercolor in the black text. He was as 
suprised as I was. We both thought that full black to any of the Epson 
drivers at any setting always printed K only. Its those kinds of details that 
make RGB quadtones such a mystery. Richard Wolfson is busy converting his 
quad system to a good RIP at the moment, and I don't expect to see him moving 
back!

C. David Tobie
Design Cooperative
CDTobie@...