What are these spots?

[Sazerac]

I've finally scratched the itch to get back into sheet film! I haven't shot or developed any 4x5 in almost a decade, so I am re-learning a couple things. I don't have a darkroom, but have successfully been developing my 135 in my kitchen and loading in a changing bag so I figured why not do it for 4x5 with the Mod54?

Anyway, I noticed these dark spots on the upper part of the image and am wondering if these are bubbles from the developing. I didn't do full inversions because I was worried about the film getting dislodged. I used the twist agitator in the Patterson tank and gave it as good of a whack as I do with my 4 reel stainless steel tank for 135. Do you think they may be bubbles rom the developing? Should I give it a harder whack next time? Thanks in advance for all advice!

[AtlantaTerry]

Since the spots are darker that means the negatives have less density in those areas. To me, that sounds as though you had less developing there. If so, I believe you are right thinking they were air bubbles on the film.

I have been developing 4x5 B&W film since the late '60s and never pre-soaked. However, starting in 2013 I started doing 5 minute pre-soaks to get rid of the anti-halation backing after reading about it here. Because of the pre-soaks there are no air bubbles. Give it a try.

[David Swinnard]

+1 for airbells. The twirly tanks (GAF IFIRC) I used with students back in the '80s were notorious for them if they didn't get a good whack on the table to dislodge the air bubbles. (whack the tank, not the students, that was frowned upon).

[jp]

It's OK to invert the mod54, just do it gently as if in slow motion. Presoak is good too, though someone will pipe in that it's not necessary or in the film mfg's instructions.

[Jac@stafford.net]

Since the dots are in the same area of each, and presuming you are scanning, I would first look for problems in the scanner.

[Sazerac]

Thanks for all the replies! I don't think it is the scanner because I see them on the negative.

I suspected air bubbles so I'll give it a good whack next time. I have a stainless steel 4 roll tank for my 135 which I don't mind whacking. I guess I was just being too cautious with the plastic tank.

[Kalvedans]

I've had a similar problem using the Mod 54. Almost every time I develop 4x5 film I get these dark spots on the negatives


I always tap the tank lightly during devlopment to avoid air bubbles. Any other ideas for how this can be avoided?

[Sazerac]

I tried the pre soak on my last round and didn't see any spots. I've also heard from another friend that my stop bath may be too concentrated so I diluted it a bit just to be safe.

[Pat Kearns]

Definitely air bells, you need more than a light tap to the tank to dislodge them, presoak should solve your problem.

[AtlantaTerry]

For plastic tanks or tall stainless steel tanks for 35mm/120/220 film, don't hit their bottoms on the sink. Just ball up one hand to make a fist then hit the tank with the meaty side of your hand next to the palm. Rinse & Repeat.

I say this because I ruined one of my home made fiberglas darkroom sinks by smacking my tall Nikor stainless steel tanks onto the sink surface. Eventually, I cracked the fiberglas which caused the sink to leak. DDT!