Zone System Testing Mystery

[tundra]

Ladies and Gentlemen, I'm losing my mind. I have done this test twice now, meter the target, put it on zone 1 (stop down 4 stops), expose it, and when I check it on the densitometer it's WAY too dense. .58.

This is Delta 100 in DD-X (1:4 10.5 minutes, 68 deg) AND Delta 100 in SP-Ultra-LF (1:9, 6:30 minutes, 68 deg).

All 4 of my meters agree within ~half a stop, so I hesitate to blame the meter, it would appear it's correct, or at least correct enough to not have me on zone 5.

I've tried 2 different lenses, and also checked the shutters, they're accurate.

No light leaks in the bellows.

Oddly, Fomapan in DD-X reads .14 above film base, exactly where I would expect. When I did the test I set it up so it was f/11 @ 1/30 and both the fomapan and the delta were exposed at that setting, no changes in light levels.

It's possible I screwed up all 4 shots in 2 film holders, but I doubt it.

I've done this test before, but I admit it was 25 years ago, so I'm rusty, but not that rusty.

Anyone have any thoughts on this? Is Delta 100 really a 400 speed film? Is the development time recommended by Ilford way too long?

Appreciate any insight y'all can provide.

Edit - should include that this is a new box of delta 100 (ex 01/2027) and a new bottle of ddx, both from B&H.

Several thoughts leap to mind here:

1) Water. In theory, it shouldn't matter, but I've seen as much as 1 stop variability in water behavior across a year. I've used nothing but distilled since.

2) Thermometer. Thermometers lie. I'd check your thermometer against another. If they are wildly different, something is wrong.

3) If all else fails, retreat to something like D-76 1:1 and try again. You may have a bad batch of developer, it's not impossible.

[mward]

I have a feeling some of the commenters here read the first post and get all excited and engage in premature explanation.

I have three thermometers, they all agree. For all the premature explanators - it turns out the 10.5 minutes recommended by ilford is bonkers. The true N development turned out to be 6.5 minutes.

I am testing SP-Ultra-LF now. That is very interesting about the water. I will keep an eye on it. Water on the boat is mostly RO water.

[tundra]

I have a feeling some of the commenters here read the first post and get all excited and engage in premature explanation.

I have three thermometers, they all agree. For all the premature explanators - it turns out the 10.5 minutes recommended by ilford is bonkers. The true N development turned out to be 6.5 minutes.

I am testing SP-Ultra-LF now. That is very interesting about the water. I will keep an eye on it. Water on the boat is mostly RO water.

I would expect RO to be pretty good. What I witnessed was with a newly built darkroom in a new home. The seasonal variability in results was 1/2+ f/stop the first year of use. I never bothered to investigate and just switched to distilled.

I would say that most suggested developer times are "bonkers". For normal inversion development, if I don't want to do densitometery, I expose at 1/2 box ASA and develop 20% less than recommended for N scenes.

For each N+- I increase- or decrease development 20%, adjusting EI accordingly.

This is not perfect, but it's close enough to get me in the ballpark where I can then tune by eye.

For really short SBRs where I want a lot of mid-tone expansion, I just expose at box speed and semistand develop for an hour.

I would note that I do not use T Grain films as I've never found them satisfying to use. YMMV

[mward]

I would note that I do not use T Grain films as I've never found them satisfying to use. YMMV

I have heard several people say that, yet both John Sexton and Clyde Butcher have gotten good results with them. Myself as well, although not to be included in that company. Usually I want t-grain when I go shooting at sunset and am getting into long exposures. The smaller changes to reciprocity are helpful. I've got Fomapan loaded if I want the regular stuff. I'll have to see how it goes. Maybe shoot one of each on each picture and see how I like the results. This is a foray back into large format again after a 25 year break because I finally got excited about a subject matter worth taking pictures of again.