Dark slide light leaks in RB67 ProS 120 roll holder

[Donald Qualls]

I just processed the first roll through my "new to me" RB67. The negatives look good, good spacing, crisp and sharp, exposure seems correct -- but there appears to be a light leak, and from where it is on the film (runs from rebate to rebate on four of the ten frames) I think it's leaking at the dark slide slot.

I've got three RZ67 foam kits on hand that I was planning to use to re-foam the three roll film holders I have (one 6x7, one 6x4.5 for 120, both ProS vintage, and a ProSD 220 6x7 that I'm using for 35 mm sprocket semi-pano until I can fabricate a mask to make it 24x72-ish).

Is there a reasonably accessible way to renew the velvet/felt in the dark slide slot on one of these?

 

[Mamiya_Repair]

To replace the springy felt light trap on the outer cassette, remove the eleven screws holding the plastic frame to the frame assembly. There is a spring loaded catch to be mindful of when removing the plastic frame.Most cases of light leaks on the Mamiya 120 backs are caused by a faulty foam seal by the back door hinge. The felt light trap does not disintegrate like the foam seals.

 

[Donald Qualls]

Thanks, @Mamiya_Repair -- I was looking at the negatives again and I think you're right, it was the hinge -- it's on the second and third frames, and then the last two. I had direct sun on my left (hinge side) for the first couple frames and a couple late in the roll, and the hinge would fog onto the frame following the one in the gate. I'll re-foam the backs as I have them empty, and meanwhile, keep them out of direct sun.

I'm very happy with the results otherwise; the Sekor C 90mm f/3.8 appears to be a nice, sharp, high-resolution lens (judging by detail I can see in the negatives). Now if I could just find negative pages that would hold all ten frames from a roll (6x7 pages hold nine) -- and I could really get used to being able to advance medium format with a lever like most of my 35 mm cameras.

 

[Alan Edward Klein]

Don, I use Print File for my RB67's. I cut the negative 3-3-2-2 to insert into these sheets. I used Style 120-4UB but it's been replaced I believe with this product. You'll need a larger binder.
https://www.bhphotovideo.com/c/prod...4UB100_Archival_Storage_Page_for.html/reviews

 

[Donald Qualls]

Thanks, Alan. I don't have any wide binders at present, but I can order some when I order the negative pages.

 

[Alan Edward Klein]

here's what the sheet looks like.

 

[MattKing]

I used to just expect to screw up at least one negative per roll.
Nine shots fit nicely on the normal negative holders.
One of the reasons why I'd like a 6x8 option.

 

[Alan Edward Klein]

Matt: I usually shoot three 6x7 pictures per scene bracketing +1 and -1. So basically I shoot three scenes per roll times 3 which leaves me one frame at the end to shoot. I never know what to do with one shot.

 

[Donald Qualls]

I've never gotten into the habit of bracketing -- but I might when I start shooting chromes regularly. Last time I shot MF chromes, 620 Ektachrome was E-4 and I metered for my Kodak Reflex II (the first one I owned) with a handheld Gossen roller blind meter.

 

[MattKing]

Donald,
The new Ektachrome is wonderful - I await some 120 with bated breath.

 

[Donald Qualls]

Matt, the chromes I'll practice on are expired Velvia. Once I'm reasonably confident I have the process in hand, I'll buy some new film -- new Ektachrome or new Fuji (Velvia or Provia, I don't really know the difference). I'll probably get some in 4x5, too. Worth every penny.

 

[Alan Edward Klein]

Don: Velvia is only available in ISO 100 in 4x5 in the US. You have to buy from Japan direct if you want Velvia 50 in 4x5. It's pricey.

 

[Jon Goodman]

If anyone needs to replace their dark slide pad, please contact me via email. The film back kits I make for the RB67 include the replacement material along with instructions and images. Also, the hinge end seal is made from a material I created long ago for use in motion picture cameras. It is a combination of foam/velvet and it will last for decades and decades and it won't leak light. If you just need the dark slide pad, however...I'm happy to send one to you.
Jon

 

[Donald Qualls]

Aaah. I bought three RZ67 kits from eBay (shipped out of Colorado, that's not you, is it?) -- there weren't any marked for RB67 and they looked like they had the number and size of strips I need for the RB67 backs (and one more, if/when i get one, since the ProSD 220 back I have apparently doesn't depend on foam). Would you sell me just the dark slide and hinge pieces for a couple ProS 120 backs?

 

[Jon Goodman]

Hi Donald. No, that person could be one of the many parasites who copied my work, my instructions, the way I walk, etc. I've seen them as distant as Irkutsk. The RZ67 is different. I have kits for that film back also, but as I said those are not exactly the same. You're right...the ProSD was designed not to need foam seals. Yes, I would be happy sell you those pieces, however I will mention the kits I make/sell include some other unique improvements (non-adhesive slot seals for one thing) designed to make the work easier. Also...very important in my opinion...since the tsunami, custom foam coming out of Japan is altogether different. Unfortunately not in a good way. As a result all the foam I use is made to my specs here in the USA. Please contact me at jon_goodman@yahoo.com I'll email you the RB67 instructions and you can see better what the process is.
Jon