Minimum Print Size

I'm in the middle of a painting repro job. The client has provided two "full sheet" size watercolors, each slightly larger than 30 inches high x 22 inches wide (76.2 x 55.9 cm). The watercolor paper has "deckled" edges, so I'll crop to 30 x 22 and my prints will have clean edges. I've completed the photography, and the color matching and other Photoshop work. I've printed some test strips, which is where this story gets interesting.

First, of course, I had to prepare the printer. Due to travel and some local photography work I'd not used the 7900 for 32 days, a long (for my machine) idle period. Seven channels showed problems on a nozzle check print. I'm fairly sure that's the worst I've ever seen. Two of those channels had only small nits missing, but the remaining five were at least 50% blank. I spent about two hours doing pair cleanings (all of them "powerful") and swapping low-quantity ink cartridges for fuller ones, but finally I had the danged thing cleaned up and ready for use. Just the usual hassle, magnified.

I planned to make a full-width test strip, but I needed only a few inches of the image's height, so I made a custom paper size of 4.5 inches (11.4 cm) high on the 24-inch roll. I set up in the usual way to make that print. Here's a screen shot of the Photoshop print dialog box (double-click to enlarge):

This clearly shows the dimensions, the image to be printed, and its location on the paper. I clicked the Print button, and then the printer produced and cut a perfectly blank 5 inch high piece of paper. This sort of thing has happened before, and it's always a WTF? moment. If you dig around in past postings here you'll find at least a couple of similar occurrences. I've never been satisfied I've found the cause, but in each case I did eventually complete the print job.

This time I decided to dig in to see if I could find any reports of similar problems and perhaps a solution. These kinds of Web searches often turn up plenty of interesting, but tangential pages. That was true of this one, too, but I got no answers to the original question.

"If all else fails, read the instructions" is never bad advice; I did that, and found nothing of use in the U.S. manual (PDFs of the manuals are available via the Web). In the European version of that manual I found this:

"Depending on the paper type, the minimum length of paper you can cut is set from 60 to 127 mm. You can not change it."

That's also less than helpful, but it set me to thinking differently about the problem. I remade my test strip so the print area would be slightly over 8 (20.3 cm) inches high. In setting up the print I made a custom paper size of 9.5 inches (24 cm) on the 24-inch roll, with the rest of the set-up identical to the first (failed) print. This printed perfectly.

That may indicate there is a minimum print size, or at least, a minimum paper size, below which the 7900 will pretend to, but not really print, generating only a blank piece of paper. There's nothing conclusive here because nothing ever is with these machines, and because I changed too many variables (both print and paper size) when doing the experiment. I don't have time to pursue this now, but perhaps next time I need to make similar test strips I'll play with only one variable at a time. If I do, and if I learn anything useful, I'll post it here. Right now I need to get on with making 12 prints for the client.

  --Jay