C 41 is the hardest of all films to develop because of short times and high temp.
It should be obvious there is not enough chemistry if the inner wraps are not developing.
I never could get the small reels and tanks to work with C41, Then I got the 2500 tanks with the big reels. The film only makes 4/5 wraps and never goes near the center.
Make sure the tank is turning full speed when you dump the developer in and keep it high for 30 sec.
Even if you have only 1 film in a two reel tank, there needs to be enough developer for two or it does not reach inner wraps.
I never use a presoak. IT IS NOT IN ANY INSTRUCTIONS. It inhibits the free absorption of developer which is critical for a short process.
1520 is a small diameter tank. 120 film is wide so it counts for two. In theory 4 oz is sufficient for one roll of 35 mm or 250 cc for a roll of 120. I can make it work with B&W and E6. Never with C41. I bought the 2500 tanks and wide reels and all was well.
I would hope your 120 is not 220 which will never work in the small tank.
You should run the tank and film empty to temper it to 38 deg c or 100 F . This takes 5 minutes. EMPTY.
Last edited by Ronald Moravec; 08-01-2011 at 02:44 PM. Click to view previous post history.