Change of density at film hanging clips on dip-dunk processing

[Tin Can]

Calumet offered in their catalogs, various gas burst schemes

For color, which I never do they had plastic 'screens' on 2 sides of sheet film

Lines of tanks, aka Tank Line in many sizes

I use three 1 gallon Calumet SS covered with adjustable plenum tanks in a bigger tank for temp control all sitting in a new cheap laundry sink

I find it relaxing as they bubble

[Bernard_L]

I think many of us have seen that, I certainly have. And it's always clearly recognizable from the geometry of such density anomalies - i.e. the typical crescents and kinks that result from the physical cause of the problem. Unlike in this case, where such a physical/geometrical pattern is not present.

Sure. But my point was not that the over-dense regions (appearing as light in the positive)

were due--specifically-- to kinks during loading or other, but rather, more generally, caused by mechanical stresses as might be caused by a (misaligned?) film clamp.

[LabRat]

It's a local agitation issue around the clips, where the bubble burst over the sheet area allows the bubbles to flow upwards, but this is impeded by the clip area... The sign is there is clearer or denser areas around clips where the "clouds" of developing by-products are not being displaced by the bubbles... The "clouds" contain by-products that can increase or decrease developing activity significantly and not being displaced/dissipated back into the solution efficiently...

Changing the style of clip to the older triangular tip that has the single bump to hold film would allow more flow through clips, or at one of my old E6 labs that used gas burst had to physically lift a rack at least once during the shorter E6 process to clear the sheet of by-products or risk uneven development... Most labs eventually went with true "dip & dunk" machines that raised the racks clear of the solutions during cycles to fully drain sheets of "clouds"... This is true with most dip hanger systems, and it also much helps to tilt hangers past 45° also for a sufficient "dwell" time to drain edges of hangers better...

Steve K

[schafphoto]

The clips do seem pretty opaque (from a liquid perspective) and i was thinking that drilling a through-hole in each clip would improve drainage and maybe the tendency to hold chems. Just a thought. More likely than welding improved clips on a valuable and rare stainless Refrema rack.

[LabRat]

But it's probably that the clips form a "shadow" from where the bubbles flow, and not getting proper clearing of the "clouds" in the clip area...


Try lifting/tilting racks during process to completely drain sheets before re-immersion a few times during dev step...

Steve K

[ASA1000]

But it's probably that the clips form a "shadow" from where the bubbles flow, and not getting proper clearing of the "clouds" in the clip area...


Try lifting/tilting racks during process to completely drain sheets before re-immersion a few times during dev step...

Steve K

It's not a shadow, it's chemical contamination. Read the excerpt from the Kodak technical publication I posted here. and Merry Christmas!!

[LabRat]

It's not a shadow, it's chemical contamination. Read the excerpt from the Kodak technical publication I posted here. and Merry Christmas!!

As in turbulence eddy...

The sign it's agitation is that the development by-products can leave denser and thinner streaks/blobs in less than ideal agitation areas due to improper agitation... It is local to the clips, enough for the "clouds" to congregate near as bubbles will flow around clips, with a "boundary layer" holding clouds and diverting flow around obstructions...

This used to happen in the E6 gas burst line labs, usually leaving a greenish blob around where they clip...

Steve K

[Mick Fagan]

I'm in agreement with Steve K (LabRat), the occurrence is the same from one side of the rack to other in each case. The shape of the issue is nearly identical and is in a consistent manner in multiple sheets. With one side being one shape, while the opposite side is the other shape.

If indeed it was chemicals being left on the clips after going through the process, then in some instances the amount of retained chemistry would more than likely be of a different shape from different runs through the bath on different films.

Around 32 years ago I left working in a professional lab where I had quite a bit of exposure to Dip "N" Dunk E6 and C41 with gas burst agitation and the sometimes many issues in development unevenness due to gas flow. Other times things worked brilliantly, but sometimes....

I also don't remember cleaning our racks, except when we dropped a bath, whether it was the E6 or C41 bath. We could sometimes put shed loads of film through on some days.

[ASA1000]

I'd start by showing him the information I posted from the Kodak Technical Bulletin. I do think contamination might be affected by gas too.

[schafphoto]

So film installed in the lower positions may be more prone to this effect.
-AnalogAngler

That's one of the things I was going to experiment with. Top of rack vs. bottom of rack occurrence. The top of the rack sheets are out of submersion in developer for longer than the bottom sheets when the rack is lifted 36 inches out of the developer tank and lowered into the stop tank.