The International standard for film/plate holders is post WWII 194/7 I think, and some new cameras still took non standard book form holders well into the late 1950's. Watson and Gandofi were two companies still making book form holders

Quote Originally Posted by paul_c5x4 View Post
I have a couple of these MPP holders - They are fractionally thicker than a regular plastic film holder and fit a modern 5x4 camera just fine. If a spring back on a modern camera can accommodate a QuickLoad/ReadyLoad holder (which my Wista does), it will cope with the old wooden MPP plate holders.

You will find Ilford also do holographic glass plates (for a price) and if you opt for coating your own, get the glass from a glazing supplier cut to size.
I must have at least 15 or 16 MPP holders now, 6 are plate holders 2 with the same film inserts, others are identical except MPP riveted the inserts in place from new. Some MPP holders have a different register as did some very early MPP cameras. I have checked mine and they are all standard. MPP holders do have slightly wider edges holding the film so the film area is a touch smaller. They are very well made and despite high prices on Ebay from certain sellers can be picked up quite cheaply. (2/$3.15 is about the average I've paid for them).