Hi Folks!

I finally got a Patterson tank and the requisite chemistry in the mail yesterday. I processed one roll of Delta 400 and in my haste I dumped the developer a full minute early, so only half the roll gave me any usable frames, c'est la vie. My second roll was much more successful, and I was able to get 24 usable frames out of it. My question is that when I scanned in the negatives there were several defects and I'm not sure if they're the result of something I'm doing during processing or a problem with the camera itself. I'm using the bog standard processing procedure as laid out in Ilford's "Processing your first B&W Film" document. This is Delta 400 film, and I'm using Ilfotec DD-X at ~21C for 8 minutes, followed by Ilfostop and Rapid Fixer at the appropriate times for each, then letting the tank sit under a running faucet for 10 minutes. After that the strips are hang-dried over the tub for about an hour.

First Problem: Negatives are too dark / Positives are washed out and too light. Here's a raw scan:
Here's the same negative with the colors inverted in GIMP:

I can't tell if these are underexposed or under-processed? I've only had one roll of film from this camera processed by a camera store, and they did a really terrible job so it's hard to compare.

Second Problem: Weird black squiggles:
playground pattern-scaled.jpg

For this image I inverted the colors, jacked the contrast WAY up, then turned the brightness WAY down, and got this image which is pretty usable, but there are a ton of flaws in it.

Okay so it makes my pictures come out old and retro looking, but that's not what I was going for. I wanted clean images with no visible grain, and that's clearly not what I got. Part of it I believe is that the 400 speed film is a bit grainier by default than I expected. However I'm not sure why those little squiggles keep showing up. They showed up on the first roll as well. Someone somewhere suggested it might be dirt in the camera? Again I've not used this camera before so I have nothing to compare it with except my other camera which I use to shoot color that gets developed at my local C-41 pharmacy, and it has had no problems. It might be worth it to run a color roll through this camera and have it developed professionally to see if something similar happens. I'm worried though that this is the result of my developing process somehow. The negatives I had done at the photo store did not have these squiggles on them, at least not that I could tell.

Thanks everyone for your help!