What went wrong with the development of this sheet?

[Photopathe]

Hi! Can anyone tell what is responsible for this pattern on this 4x5 sheet. I used 1h stand development Rodinal 1+100 (continuous agitation for the first minute) in a SP-445 tank. Everything was room temperature. There were 2 sheets in the tank and curiously one came out fine.
Thanks!

 

[Donald Qualls]

Those look like convection cells, which can form if the film is lying flat, face up, during stand development. There's enough density change as the developer locally exhausts to drive convection, which will form small columns the way rising air produces cumulus clouds on a sunny spring day, or even heating will do in water (they become visible if there are particles in the water, like coffee grounds or grains of cous-cous)

 

[pentaxuser]

Donald can you expand on this to say why his other sheet should come out fine in this situation? Thanks

pentaxuser

 

[Donald Qualls]

Donald can you expand on this to say why his other sheet should come out fine in this situation? Thanks

pentaxuser

A sheet that's face down will have much less direct effect -- convection will draw fresh developer from the edges, across the emulsion, rather than dropping it in from the top. This crosswise motion will tend to even out the development rather than emphasize the unevenness.

Of course, this presumes that the SP-445 actually wound up lying on its flat side, instead of standing upright...

 

[Photopathe]

Thanks Donald! I think you are spot on. It was the first time I was using the SP-445 and since I was doing a stand development I had this idea that maybe I would reduce the risk of bromide drag by putting the tank on it's flat side. I realize now this was a bad idea.

 

[John Wiegerink]

Thanks Donald! I think you are spot on. It was the first time I was using the SP-445 and since I was doing a stand development I had this idea that maybe I would reduce the risk of bromide drag by putting the tank on it's flat side. I realize now this was a bad idea.

OMG, don't say the words "stand development"! Get ready for the mortar attack. They'll be dropping them in on you shortly. Run for cover!

 

[MattKing]

since I was doing a stand development

Or perhaps more appropriately in this case, a "lie on its side development".

 

[Donald Qualls]

The lowest agitation I've done was every 3rd minute, with 50% increase in time for the same dilution and temperature. Never tried anything longer or lower agitation than that.