Small tank agitation w/reels - uniformity?
I've researched this everywhere I can, read everything I could find, and am still failing to achieve uniform development across 35mm roll film frames when developing in small tanks.
But only with modern films i.e., 400TX, 125PX, and HP5+. For some reason regardless of agitation technique uniformity is quite good with Arista EDU Ultra II 200.
I've tried slow inversion, 'torus' rolling, vigorous fast inversion (as if tossing a can from hand to hand including rotation), single reel tank, double reel tank with empty reel and enough chemistry for only one reel, etc. and I end up with either bromide streaks from the sprocket holes, clouds around the sprocket holes, or excessive development along the edges. The streaks and clouds are always on the side of the film nearest the top of the chemistry surface when soaking.
Out of all the options a relatively slow hand-to-hand can-tossing technique seems to work best with rapid inversion and rotation but no large vertical movement or shaking. Uniformity is still not perfect though. I use the same technique for stop, fix, and wash, fwiw.
I thought using half the chemistry of a two reel tank would work better than a single reel tank with the same amount of chemistry but there's no substantial difference that I can see. Maybe I'm not allowing enough dwell time at the end of each inversion. I'm stumped and it's getting aggravating after a lot of film. The few rolls that've come through OK are way overdeveloped (but that's a separate problem) and I've no real idea what was done differently with them - figures.
Any suggestions, pointers, youtube video references, etc. would be greatly appreciated. TIA
What developer are you using, what sort of developing time, and do you presoak?
I'm wondering the same.. What developer?
Are you getting bromide drag from a formula with too much bromide? Also, is your tank one of very small volume, and is the reel in it too tightly? I've found that I get best results when using tanks that allow the reels to move around a little during agitation. When you can hear them going "clunk" (steel reels & tank), then all is good.
Thanks guys, forgot those pesky details.
This seems to be true using PF TD-16 1:1, XTOL 1:1 (to a much lesser extent), HC110 (D) (a bit less of a problem), and especially PF DD-76. The tanks are Kindermann or generic SS with Kindermann lids, the reels are Hewes, and I can feel the reel moving in the single tank but not so much the reels in the two reel tank. I use 250ml of solution to keep things simple and it's more than enough to cover a reel with film although not by much.
Most of the tests have been with 12exp rolls although some 30 and 36 exp rolls aren't substantially different. I have to say though that the worst uniformity is on the frames near the outside of the reel which doens't make a lot of sense. Also, come to think of it, I've used 4-reel tanks with the loaded ones at the bottom and another spaced with an empty reel between and another above, using a lift rod. The bottom reel was more uniform but excessive dev along the edges while the upper reel showed clouds along the topmost edge. The 4-reel tank is always used with 850ml of solution.
Developing times are anywhere from 2-12minutes. All chemistry is brought to temp in 1000ml pyrex beakers in a tempering bath and temp compensation is achieved using an RH Designs ProcessMaster II. A digital thermometer is used to make sure all solutions are within a half degree C of each other and the bath prior to starting.
No presoak is used but the tank is dropped back into the tempering bath between agitation cycles. Cycles are continuous for the first 30s (<5min total) or 60s (>5min total) and two inversions every 30s or 60s, respectively. Stop is continuous agitation, fix is the same as develop except the number of inversion cycles is 10 instead of two. Drain and fill is attempted to be complete within 10s although that's not always successful.
Lessee, what else? All chemisty is made in lab glassware with boiled distilled water and stored in Qorpak amber Boston Rounds with teflon lined caps. Fix and stop are mixed with unboiled distilled water as needed, stop for DD-76 is plain DW. Wash is plain DW held in beakers as well. Other than the stainless probe of the digital thermometer the chemistry never contacts anything but glass. Bottled chemistry is stored in the dark but temps range up to 80F during the summer. No chemisty is more than a couple of months old. If I missed anything, please let me know.
Try using just a little more developer. Sounds like you might be losing a little on inversion and that top edge of the film may be fully submerged only part of the time. Your initial agitation time seems more than adequate, but the number of inversions per cycle is kind of low and slow. Try doing 5 quick and snappy inversions in 5 seconds each 30 seconds, or 10 in 10 seconds each minute. You really can't overdo this. Most of the problems I've seen have been the result of timid agitation techniques rather than too vigorous.
Originally Posted by justpete
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FWIW, I do 4 inversions at each agitation, never do developing times less than 5 minutes, and usually use Xtol at 1:1 or lately, 1:3. I process roll films in stainless and always fill the tank, with reels, and solution, always at 68/20 deg. No problems with uneveness or bromide drag.
PE convinced me to pre-soak, but I didn't for years, and haven't noticed a difference in terms of even or uneven development either way.
My advice would be similiar to Franks, more chem, two reels in a two reel tank, more or more vigorous agitation. If that doesn't resolve it, try pre-soaking, especially if you're processing for very short times.
I would strongly suggest staying away from combinations of film, developer and temperature that result in times less than five or six minutes !
Also, the agitation sometimes sounds extreme - after all, the aim is to get fresh dev at the film regularly, rather than to create localised high-speed swirls of developer. A couple of slowish inversions (four or five seconds each) per thirty seconds, with a 1/3 turn of the tank when you put it down (to avoid any accidental repeated effect when doing the same thing every time) works fine for me.
If you do a test with the wash-water and take the lid off a tank to look at how long the liquid takes to get out of the funnel and down into the tank (when there is film in the reel), you will see that it is several seconds. Inversions more rapidly than that time, may just make for foamy developer and possible marks at high-speed flow locations around the reel, especially if you do repeated high-speed inversions in exactly the same way every time.
As mentioned by Frank above, The volume of developer also needs to be enough to comfortably cover the reel(s), as well as having enough active developer to do the job, though that should only get tricky with high dilutions of course.
Unless you have really disgusting tap-water (ie. fine sediment, or not for human-consumption), then you might be able to save some money and gain convenience by just using filtered-water for everything except the final rinse.
All this works fine for me anyway.
I use the same brand of tank and reel, but in the 120 size and have always filled the tank with 500ml of developer; this pretty much completely fills it up. I've never had any problems with this set-up but did experience some similar problems with a palstic paterson tank which I didn't fill all the way because it could take a litre of liquid.
I've always been surprised how vigorously you can agitate the tanks without getting any problems (except maybe higher contrast negs). There are a number of videos on youtube that show people developing b&w film, maybe you could have a little look to get an idea of how much you can agitate while developing.
All good suggestions above. The only thing I can add is to increase your development times to close to 10 minutes (find the temp and dilution to facilitate this), use enough developer to FILL the tank, and don't agitate too vigorously. Try a higher dilution for HC110, or D76 1:1. I've never used Xtol.
"I'm still developing"
Agree wholeheartedly with the 'fill the tank' recommendations.
I had your problems when I was doing the 250ml in the 500ml tank, way too much 'sloshing' going on and a huge amount of flow through the sprocket holes.
I went to filling the tank completely and I think you'll find your problem goes away if you do the same, coupled with gentle agitation to prevent highlight blocking.