QTR-Quadtone RIP

silviapestalozzicolor wrote:
> Immediately after printing i get a 1.38, six hours later the same print measures at 1.52 with a Techcon RT-112 on PhotoRag Bright White. About the same on Innova Smooth Cotton. For comparison i have here a K7 promo sample printed on Smooth Cotton by IJM/Cone that measures at 1.64 has great dynamics and looks like it's a completely different inkset. Lately i have heard some people complaining on the lists about flat K7 print results. Have there been any manufacturing issues with the Neutral K7?
It's not the inks. It's just inexperience. The Cone inks are well known 
for this. It's even picked up a name -- I've heard it called "digital 
dry down." What happen is, as the glycols and glycerins in the ink 
carrier evaporate (much slower than the water) the inks get darker. All 
of the inks. Clearly the effect is most dramatic in the black ink which 
can increase in Dmax by a stop. Some see more. But the effect seems to 
be non-linear over the range from white to black.

The way I deal with this is to dry work prints with a hand held hair 
dryer. High fan, low heat. If you put a hand on the underside you can 
feel the stages - first the water goes, then the glycols. You can smell 
them coming off too. You can dry a print like this days later and still 
smell the glycols coming off.

I strongly recommend that any linearization targets be dried with a hair 
dryer before measurements are taken.

Interestingly, if you'll dry the prints with a hair dryer, you are also 
defeating the out-gassing problem that all pigment inksets made to date 
seem to share. I've made a print, dried it and framed it, print to 
framed and on the wall in an hour. No outgassing. A print that I framed 
six weeks after printing (but without drying with a hair dryer) 
outgassed all over the glazing the next day. Hmmm.....
--
Bruce Watson