bro, if the light leak should be from top down when u are doing portrait orientation, then its not the felt cos that part of the grafloc back has no felt. that part of the camera and the film holder has a design that caters to block stray light from going into the sheet film. check your film holder and grafloc back for nicks and chips.
Its the Fidelity Deluxe I have
Riteway vs Lisco/Fidelity
Older Riteway Cut Film Holders (the ones with the metal handles on the darkslides) are more highly regarded than say older Lisco. The Riteway holders seem to hold up better. When I worked in a studio about 15 years ago, my boss had over 100 holders all of which he had bought used. Probably all but about 5 were this style Riteway and none of them leaked light. Of the Lisco holders he bought, the failure rate (of used holders) was high enough that he quickly stopped getting them (maybe 50% of the ones he got leaked).
The current Riteway holders are made by the same company as current Lisco and Fidelity holders (these three companies merged probably 20 years ago). The Lisco and Fidelity holders are identical except for the name and slight differeneces in the pattern embossed in the plastic. The Riteway holders also appear identical except for the automatic locking built into the darkslides, and the very cheezey number wheels for marking negatives. I have 2 of the current Riteways and lots of the current Lisco and Fidelity holders. I can't stand the Riteways. The lock on the darkslides takes quite some effort to unlock on my wooden camera and make it very easy to move the camera when removing the slide. The number wheels turn way too easily and the numbers extend into the image area. The different handles on the slides make the holders too large to fit in the quart size Ziplock bags I use to keep dust out of my holders. None of my holders (all bought new) have ever had light leaks (except the one slide I managed to crack, the holder itself was fine once I replaced the slide).
If I were were
buying used holders, I'd look for the older plastic Riteways with the metal slides. They seem to hold up much better than other holders of the same age. If buying new holders (or used current style holders), I'd avoid Riteways for the reasons mentioned above. John Sparks
Hi John, My experience with old holders (4x5) is the same. The Riteway holders all are fine, the film plane is in the right place etc. I have a box full of Lisco and Fidelity holders most of which have warped, or maybe were just not accurately made, and are not useable. This is a matter of the film plane rather than light leakage. I started measuring holders after getting unexplained mis-focussed pictures. I found the film-plane to vary all over the place in all but the Riteway holders. OTOH, later 8x10 Fidelity's seem to be ok. Richard Knoppow.
How to isolate a bad 4x5 film holder giving unsharp images ?
You can measure them using a depth micrometer (one good enough is about $30 US) and a plate of sheet aluminum with some holes drilled in it to clear the micrometer. Measure with a sheet of scrap film in the holder. The distance from the reference surface of the holder to the film plane should be 0.187 inches (I think this is the right value). check the corners and center. It should be very accurate and should show no signs of warping. If your holders are reasonably new you may find they are all OK and the problem came from mis-loading the film. Its all too easy to miss getting one edge under the rail. If you find a bad one keep it for spare parts, especially the dark slides and end flap. Richard Knoppow