Digital BW, The Print

I printed a yellow patch and then ran the paper through a second time
and overprinted with a cyan patch.  The reverse was also done, first
cyan then yellow.  A third paper had one patch with 100% yellow and
100% cyan printed in one pass.  All three looked different.  

It seems to get the correct blend of two colors, or grays for that
matter, each dot must be printed adjacent to another but not on top of
one another.

CMYK printing employs subtractive color theory whereas RGB is  
additive color theory. This requires that the inks be transparent  
since the light passes through the inks, which act like a filter,  
hits the paper and reflects back up to your eye.  Theoretically, cyan  
is white light minus the red, yellow is white light minus the blue,  
and magenta is white light minus the green.  That said the  
transparency of inks is not always 100% pure. I think the yellow is  
the worst offender. I'm not surprised that your test green looked  
different. My guess would be that the one with the cyan on top would  
be a bluer green whereas the one with yellow on top would be less  
blue-green.

Clark
On Nov 22, 2006, at 1:24 AM, elauq wrote:

> I printed a yellow patch and then ran the paper through a second time
> and overprinted with a cyan patch. The reverse was also done, first
> cyan then yellow. A third paper had one patch with 100% yellow and
> 100% cyan printed in one pass. All three looked different.
>
> It seems to get the correct blend of two colors, or grays for that
> matter, each dot must be printed adjacent to another but not on top of
> one another.
>
>
> 



[Non-text portions of this message have been removed]