…I am running Leopard on a new iMac…
No way. !!!
The minimum system requirement for CC is Lion, OS X 10.7.x. No "new" iMac can run Leopard.
I see the error of my ways, I meany Yosemite, not Leopard,\... my bad.
You are very, very confused.
Your screen shot clearly shows you are running OS X 10.10, a.k.a. Yosemite, not "Leopard".
Yosemite is Apple's latest version of Mac OS X. "Leopard" was an old, by now obsolete version, namely Mac OS X 10.5.x, or five (5) MAJOR versions ago and a monumental piece of cr@p. It does not run on a modern Mac, and Photoshop CC would not support it anyway.
Okay I'll start fresh.
I have a new iMac that is running Yosemite v10.10. I have an Epson 4900 Printer with updated drivers. I am using Photoshop CC(Creative Cloud).
When I attempt to make a 25X17 inch print on Exhibition Fiber from a 100 foot x 17 inch roll, all that prints is a 7x11 portion of the image set off-center on a 17X18 1/2 paper.
I have a MacBook Pro running Photoshop CS6 and it prints fine. So I assume it is an Adobe CC or Apple issue.
If anyone else has this problem or knows of a fix, please let me know.
Thank you in advance.
Screen shots of the pertinent dialog boxes would be very helpful, especially your Print dialog box, as well as your whole canvas.
If you do come back, please give the exact versions of your OS X 10.10.whatever and of your Photoshop CC 14.x.y, so that others who are running them (not yours truly) can tell you whether you are fully updated or not.