"Many comments I have read state that it's the scanning process that causes this shift, such as the green cast is due to underexposure, and the scanner (i.e. the scanner software) is trying to bring up the shadows causing the color shift"
That could be. I exposed these at box speed, but as you know conventional wisdom would suggest overexposing negative film a bit. Portra 400 would have certainly been a better choice for this light, but I wanted to test the 160, darn it.
My next casual test will be exposing it in mid day light with bracketed overexposure. Not today though, 101°F in the shade.
"Also if you look at the wall next to the door there is a dark gray rock just below the level of the iron hinge... you can see the color shift in that rock from image 2 -> 3 -> 4 (it's kind of like a gray card that shifts). "
That frustrates me. When you have a series of photos you want the color to be consistent. I'm trying to avoid the requirement of becoming a Photoshop pro to get the results I want but perhaps some color correction practice is in order.
Then again there's still plenty of Tri-X in the fridge
I'm glad to hear you're going to run some Portra through your camera! Looking forward to seeing the results.
Thanks for the comments Casey,