encroachment
Click on the image once, then you can use CTRL and SHIFT to zoom in and out, and the arrow keys to move around.
If you are on an Apple device, drag your finger on the image to pan around. Pinch/unpinch on the image to zoom in and out.
Ok. I think I'm reaching the limit of what my computer can handle. This one is 96"x144" at 240ppi. That's 23,040 pixels wide by 34,560 pixels tall. I managed to crash Photoshop once (thank goodness for frequent saving) and it took me about 6 hours to get this far, before I decided I'd had enough. As much as I would like to go even larger, I think that until I can upgrade my computer, I'll hold off and focus more on composition. It's just not fun making brush strokes that take half an hour to complete.