I have not even started with my 1800's Bausch & Lomb. Except to get the pneumatic shutter workinng.
I have been doing some research on the Korona and found an online copy of the original 1900 catalog. It was designed for glass dry plates. Judging by the wear on the paint on the back apparently someone had been using a more modern holder at some time. I believe that the chances of finding the correct holder are slim and then it would be for glass plates and not film. So I believe adapting the camera for film holders seems the best option. However, considering the expense and increasing paucity of film, maybe in few years I will be needing to make my own glass plates and will think differently.
I wonder if in the long ago past there had been a great debate of glass vs. film as the debate in the recent past of film vs. digital.
I have measured the ground glass position of the Korona and found that it exactly matches the film plane in a current Fidelity holder. The modern holder appears to be thicker than the original plate holder but easily fits under the ground glass frame. The modern holder is narrower on the short axis by less than 1/4 inch and shorter by much less in the long dimension only if the film openings of the holder and back are aligned. The most significant mismatch is the ridge on the back and the ridge on the holder.
I believe that I will have to make a groove in the back to recieve the holder and provide a flat fit and a light seal. The ridge on the holder creates a tiny misalignment of the film plane at the darkslide end and a light leak measureable with the flashlight in the camera test (which turned out much less of a leak than I expected). I plan to make the groove exactly the width of the ridge on the holder to help in centering the holder. My plan is to then make some removable wooden shims to assist in positioning the holder when inserted into the back.
I did not want to file off the ridge on the back unless absolutely necessary, but I believe that I will have to file it whereever it interferes with the holder once I make the groove. At worst I will file it only exactly the width of the holder to assist in centering the holder, and leave the camera more or less useable with the plate holders, if I ever find them.
So far I have replaced the bellows, repaired cracks, replaced all the missing/damaged screws (repositioned one screw in the front standard that was misplaced at the factory and interfered with the lensboard), made an extra lensboard, made all of the missing/damaged metal parts and made a few impossible to find screws. I am still under budget (including time and labor) compared to purchasing a new or restored 8x10 camera with a wooden tripod.
I love this camera, it really lives up to the "Compact" name. It weighs much less than my 5x7 and some of my 4x5's, yet fares well in sturdiness and has moderate but reasonable movements. It even nearly rivals the weight of one of my 12 inch lenses. I cannot wait to expose, process and print the first sheet of film with this camera.