The Humidity Factor

I've got a show to hang in a couple of weeks. Between now and then I'll be camping in Glacier National Park for a few days. I have the rest of this week to make any additional prints I'll want for the show. I'll finish the framing when I get back from the park. Most of the printing is done, except for a few I want to print on mat papers. Yesterday I switched from PK to MK, and just like the last time I did this, the printer did not run a cleaning cycle after the ink swap. When the switch completed I ran a nozzle check print and found no problems.

A panorama of an image from Freezeout Lake, along the

Rocky Mountain Front. This is printing on Moab Entrada

Natural. The finished print is 39 inches (1m) long. You can

see the photo here (it's the first image on the page).

There's been much debate in the usual forums about the affect of humidity on these machines. Some say they see more nozzle clogs (I prefer to think of these as "ink delivery problems", in which I'd include clogs, but also other reasons for missing nozzles in the check prints) when humidity is high, while seeing their problems diminish in lower humidities. Others report exactly the opposite; for them high humidity means fewer clogs. "High" and "low" aren't clearly defined in these discussions. The debate continues, but without more than anecdotal evidence one can only conclude that humidity may play a role. It seems there are more reports of issues with higher, rather than lower humidity.

Here in western Montana, we get most of our rain in May and June. That's been true for this year; in fact we've had record rain amounts all around us, and I've been seeing decent levels in my rain gauge lately. As you'd expect, this means humidity levels, which are typically quite low and drop lower during summer, have been higher that usual. When I printed my nozzle check yesterday, my low-cost digital hygrometer showed 63%RH, a full 20 points higher than I've seen in the room nearly the entire time I've owned the 7900. The nozzle check print was fine, and the dozen prints I ran afterward (MK ink on mat papers) were also fine.

Our rainy season will pass as it always has, it'll get hot, and very dry (our rainy season gives way to wildfire season). I record the room temperature and humidity on each nozzle check print, so I'll continue to watch this, and perhaps determine, at least in my own printing setup, the impact of humidity.

  --Jay