Jobo 4x5 film retainers for Multitank 2

[Accordionist]

Hello, do anyone here use these plastic film retainers in Jobo Multitanks when developing in rottary processors? My friend says, that these holders can cause streaks and another defects. But without these holders sometimes film moves out from the reel. So, do you have any problem with retainers or should I buy them?

[Lachlan 717]

Are you referring to the "scoops" that attach the the reel (2509n)?

[Brian C. Miller]

I think that what you are referring to are the "wings" on the 2509N reel. These are used to hold the film in place, and keep it uniform. The 2509 reel (no "N") is an earlier version, and does not have these pieces. The 2509N reel should always come with the inserts.

The 2509N reel is meant to hold four 4x5 sheets. While it has three slots, if the middle slot is used for film then it won't get proper circulation of chemicals into it. There has been some discussion of the 2509N reels on the forum.

[Accordionist]

Yes I mean these "wings".
pic

So, when I develop 6 sheets, these "wings" may cause problems... I will try to find the discussion about 2509N reels thank you...

[Accordionist]

After reading some advices here on forum, I can say only that, there are two groups of pepole which some says, that these wings cause problems and the second one says that these wings are solving problems with uneven developement. So, again, I must do my own tests

[Lachlan 717]

I think that what you are referring to are the "wings" on the 2509N reel. These are used to hold the film in place, and keep it uniform. The 2509 reel (no "N") is an earlier version, and does not have these pieces. The 2509N reel should always come with the inserts.

The 2509N reel is meant to hold four 4x5 sheets. While it has three slots, if the middle slot is used for film then it won't get proper circulation of chemicals into it. There has been some discussion of the 2509N reels on the forum.

These "wings" are NOT to hold the film in place; the reels have locating lugs to do this. The "wings" are to scoop up chemicals as they go through the fluid.

Second, the 2509n reel IS made for 6 sheets, not the [maximum] four you refer to. This is made possible by the aforementioned scooping effect, allowing consistent and repeatable induction of the film into the fluid.

Perhaps you were referring to the non-N version of the 2509 reel, sans the scoops/wings?

[Accordionist]

I don't understand, how should these wings homogenise movement of chemicals. If i use them, then movement of the chemicals on the first two sheet must be different than on the third. Or no?

[Paul Bujak]

As the wing enters the liquid, it scoops up some amount and as rotation continues, delivers it to the sheets following it. When rotation reverses, the opposite edge does the scooping. This enables all the sheets to be wetted with fresh solution without putting undue stress on the films.

The hardest part, imo, is to properly attach the wings, working in the dark. I recommend always using them.

Paul

[Brian C. Miller]

Scoop??

See attached photos. This is how I've been using it, but with two sheets, emulsion facing out and in (i.e., back to back). The only time that the chemicals would be scooped is when the inserts are not in place.

If three sheets are loaded per side, with the inserts in place, then the middle sheet won't get the same type of even agitation as the outer sheets. The middle sheet's chemicals will be surging in from the side, not passed through the chemicals evenly.

[domaz]

Hmm it sounds like we need a fluid dynamics simulator to figure this one out. Or someone could make a plexiglass version of a Jobo tank so we could see what is actually going on. All I know is that I've never had a problem developing 6 sheets at a time with the wings.