Dip and Dunk Mottling - Relationship to developer

[bspeed]

Hi, Is there advice, knowledge that someone can bestow upon me...

Is mottling a problem that can be worse in different developers ?

I have a few badly mottled from today's processing in D76 at 1:1 using published times for hp5+. 11 Minutes.

A week ago I used HC110 Dilution B cut in half at 10 minutes no mottling seen.

Or did I just screw up somehow? ;)

Could a somewhat depleted fixer cause it ? The fixer is shared among students, and gets poured back into the 2 gallon jug. It was clear/not discolored.

Thanks kindly :)

[Gem Singer]

Hi Brian,

Depleted fixer doesn't cause mottling. If there is a milky look to the film after it is fixed, it will clear with further fixing in a fresh fixer solution.

If you're certain that what you are seeing is actually mottling, you probably screwed up during in the development stage. Perhaps your D76 was accidentally was contaminated or improperly mixed.

Most development goof-ups happen during the first minute of development. The dip-and-dunk method requires constant agitation during the first minute.

One other cause of mottling is a stop bath that is highly acetic.

[bspeed]

OK, thanks Gem;

I did not agitate the 1st minute, so there is that foul up. I do believe I did do that, at least for 30 seconds with the HC110 last time around.

I agitated by your method - which mirrors Ilford's reccomendation, once per minute.
Lift, 90 degrees drain, dunk, lift 90 degress opposite drain, reinsert for next minute.

The mottling occured on the background of a portrait subject, the background was white paper, and the exposure was spot meter the face + 1 stop.

By using levels in the scanner software I did take out most all the mottling at some expense to the subject ;)

[Gem Singer]

Brian,

That first minute of agitation is critical. Also, it helps to pre-soak the film for a minute, or two.

Just remember to tilt the hangers after lifting them, otherwise there is danger of creating surge marks.

Surge marks occur when the hangers are merely lifted and re-inserted back into the developer, instead of tilting forward and backward. They show up as streaky vertical areas running perpendicular to the 4" side of the sheet of film and are caused by the developer surging over the film and causing overdevelopment. These marks usually show up in areas of sky.

[bspeed]

Thanks, the clarification of Surge and the Surge marks helps :) Not sure I have seen those..... yet :)

[Gene McCluney]

I have been developing sheet film from 4x5 to 8x10 on hangers for over 30 years in 3.5 gallon tanks. One thing I can absolutely say is that every b/w film responds differently to agitation technique. Some films require rather vigorous lift and tilts, and require them often (every 15 seconds) to avoid inconsistencies in processing, other films are quite forgiving, and can product beautiful negatives with one lift and tilt cycle per minute (after the first 1 minute of continuous agitation). There is one "given" though for even processing on hangers (for me) and that is to give the film a water bath presoak (with agitation) for up to 4 minutes before developing. I base all my techniques on my own personal experiences.