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Accordionist
19-Jan-2011, 00:05
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
19-Jan-2011, 00:24
Are you referring to the "scoops" that attach the the reel (2509n)?

Brian C. Miller
19-Jan-2011, 01:03
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
19-Jan-2011, 01:12
Yes I mean these "wings".
pic (http://www.astronomy-pictures.net/telescopes/telescope-image-large/jobo-2509n-4x5-sheet-film-reel-with-film-retainers-new_250729690216.jpg)

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

Accordionist
19-Jan-2011, 02:57
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
19-Jan-2011, 03:36
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
19-Jan-2011, 04:55
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
19-Jan-2011, 06:20
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
19-Jan-2011, 12:18
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
19-Jan-2011, 12:41
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.

onnect17
19-Jan-2011, 14:37
A couple of notes. It's easy to make the 4x5" flaps using the 9x12cm size.
Also, you can make a plastic part to do the same job in the 2509.

Lachlan 717
19-Jan-2011, 16:51
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.

Brian,

These bits of plastic pivot on the nipple that they sit on. Thus why they attach in the middle. When the drum commences its roll, the leading edge of the "wing" catches the fluid and is forced down. This action causes a hydrofoil-effect, redirecting the fluid up the face of the wing and into the area where the film sits.

Once the drum has finished its revolution in one direction, the change in direction causes the opposite effect on the wing, pivoting it, too, in the opposite direction. And the hydrofoil-effect is reversed.

It seems to me that not having these wings in place would potentially subject your top (i.e. inner) sheet to erratic immersion, as there is nothing directing fluid in its direction. Perhaps you overcome this by increasing fluid volumes so that the top/inner film channel is fully immersed?

If so, I'll stick with using the wings (as intended) and reduced fluid volumes, making processing cheaper.

Ari
19-Jan-2011, 16:58
All I know is that I've never had a problem developing 6 sheets at a time with the wings.

And I've never had a problem developing 12 sheets at a time without the wings.

Lachlan 717
19-Jan-2011, 17:00
And I've never had a problem developing 12 sheets at a time without the wings.

2 sheets, back to back per slot?

Or 2 reels of 6 sheets at a time?

Brian C. Miller
19-Jan-2011, 18:33
Lachlan, I'm with domaz on the Plexiglas drum idea. But this can be verifed just by photographing an evenly-lit white wall and then pushing the development. If there is any turbulence surge pattern on the middle sheet, it will certaintly show up. The next time I do something pushing two stops, I'll remember to do this test.

The outer edge would be the one with any "scoop" potential. That edge is awfuly small, and the insert is snapped in there against the film rather firmly. I can't imagine any significant hydraulic action is produced at the Jobo's operating speeds. If significant fluid went under that lip, it would then be going to the inside of the reel where the developer is in the first place, not in between the sheets. The significant amount of chemistry would have to reach the middle sheet through the spool's sides.

Dietrich Floeter
20-Jan-2011, 09:32
I don't mean to hijack this post but knowledgeable people seem to already be reading. I recently bought a 2508 loader because my fingers are not cooperating enough to manually load the 2509N reels. The guide on this loader seems backward to me although it appears to have been used and was apparently fully functional for someone else. If there was a left handed and backwards loader this would work but I have never heard of such a thing. The attached photos tell the story.

Am I nuts or is this thing really backwards?

Thanks.

Accordionist
20-Jan-2011, 13:00
dfloeter - Here is the manual from Jobo click (http://www.jobo.com/jobo_service_analog/us_analog/instructions/instructions_load_reels_4x5.htm)

Brian C. Miller
20-Jan-2011, 13:24
I bought mine new, and then the loader guide broke. I fixed it with industrial-strength double-sided adhesive tape.

Did you buy yours used? Does it look "fixed?" Can you use it if you flip the reel over?

I found that I don't need the loader if I load the reel on its side. I can easily feel the slots and thread the film in against my fingers.

Dietrich Floeter
20-Jan-2011, 14:13
Thanks for the ideas. I had read the directions but that didn't really help me here. Using the loader backwards will work, I just need to install a second guide pin (short brass shaft) which won't be too hard, and operate left handed. I am left handed and this could be a positive. I am still puzzled how this thing ever became backwards to begin with. There are no signs of the hinge ever having been glued on the other end and in any case would have covered the Jobo logo and that would have been a lousy glue surface.

Carrying on and thanks again. for your input.