So, I encountered something in my pictures yesterday and I thought it might be a light leak. I think it still is. Mamiya Universal with a Graflex RH8 back. Seals look OK, but it looks like it might be leaking of the far left and right--almost about 6x9 size---
After scanning the negatives I'm beginning to think the leak might be in the hinge. I can maybe tape that area--I'll have to look it over again. I did take my Mamiya 70mm back and shot with it--I'll develop and scan those negs tomorrow.
Interestingly, the ProSD back won't mount on the Universal. There is a tiny ridge that prevents its from mounting. There are a few other things I learned about the Universal and the 70mm back--I'll leave that for later.
Your RH8 needs a CLA. A CLA should correct the spacing issues. Check the insert to shell fitting in the closed position noting any play. Check the shell closed without the insert installed for mating at the hinge and latch. Put an 1/8 inch wide strip of velvet or thin yarn in the camera side of the shell at the hinge gap to seal a leak there, or the same on the latch side for leakage there. https://graflex.org/helpboard/viewtopic.php?t=6391
A RH8 is a Graphic 23 with the rapid advance lever in place of the knob.
Interestingly, the ProSD back won't mount on the Universal. There is a tiny ridge that prevents its from mounting. There are a few other things I learned about the Universal and the 70mm back--I'll leave that for later.
Charles, you neglected to mention that RH shells have a pin roller at each end of the gate. Earlier Graflex shells as delivered with knob wind inserts usually don't have the pin rollers, although late ones do. Inserts interchange freely between the two types of shells. I've bought RH shells with knob wind inserts.
Good news. No light leaks in the camera from it's back through the G adapter. It's got to be the hinge of the RH8. I ran a Mamiya 70mm back yesterday with expired Portra 400BW and no signs of light leaks anywhere. The 70mm back is supposed to roll perforated film through it but I've done some unperforated through it, though I probably won't too often. I have another back for that.
The seller told me he would refund me enough money to buy another RH8 back so that's good news.