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Delta 400 film speed test......puzzled?

John Wiegerink

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I just did a film speed test for Delta 100 and Delta 400 in Perceptol 1+3 and I'm a little puzzled. I haven't used Delta 400 in Perceptol, but have used Delta 100 in it. My EI for Delta 100 is EI64 which is .10 over FB+fog according to my densitometer. That sounds about right since I have used Perceptol with other films and get anywhere from 1/2 to 2/3's stop less speed with Perceptol 1+3 over other developers like Xtol. Now for the Delta 400 test? I can only get an EI of 120 at .10 over FB+fog with Delta 400. Has anybody else experienced this with Delta 400? Like I have said, this is new film to me and I'm curious. HP5+ gives me slightly more than EI200 in Perceptol 1+3 and that's why I'm puzzled. I'll be doing two further tests of Delta 400 in Pyrocat-HDC and Xtol-R so we'll see what that brings, but in the meantime I'm scratching my head.
 

Couple of quick questions:

What was your developing time?

Secondly, Did you use 240-250ml of stock solution per 80sq in of film?

I've tended to use 10 mins at 1+1 in ID-11 for Delta 400, and rating about 200 (often with a Y2 filter, which I add a further stop of compensation for, thus realistically EI of 100) - shadow detail is fine & it prints stunningly easily and beautifully.
 
I ran my time at 22 min. @ 68F for both the Delta 100 and 400. I develop one 120 roll in a two reel tank with a 35mm reel on the bottom, 120 reel in the middle and another 35mm reel on top so there is plenty of solution for one roll of 120. I can see 2/3's stop speed loss for the Delta 100, but 1 2/3's stop loss for Delta 400 seems a little much. The only variation in the test was that I used 1/30 of a second on the Hasselblad's 80mm f2.8 Planar for Delta 100 and had to kick that up to 1/125 of a second for Delta 400. I might do another test using my other 80mm Planar to see if there is a difference, but I doubt there is that much difference.
 

That all seems to check out - I take it you mean a 2-reel 120/ 4 reel 135 stainless tank? 22 mins seems acceptable to me timing-wise.

That it's off by pretty much exactly 1 stop from what you'd expect suggests operator or mechanical error at the exposure stage - I'd probably try another roll and see what happens - hopefully the lens isn't playing up!
 
Yes, it's a 2-reel/120 tank. I'm very sure it wasn't operator error, but anything is possible. I have been around cameras and shutters for a very long time and just by ear the 80mm Planar's Compur shutter sounds very near on at 1/30 of a second. I would think that at 1/125 of a second an error would go the other way. Another words, the speed would be slower than 1/125 of a second and not higher(in this case) if the shutter speeds were off. But again, who knows! I'll keep trying since that's all I can do I guess.
 
Did you develop to a gamma of 0.58 for both films? Since you have a densitometer, gamma is easy to determine (assuming you're shooting a step-wedge).
I suggest shooting both rolls at the same shutter-speed, because the aperture is likely to be more accurate than the mechanical shutter.
 
This was just for a EI film speed test and I developed for the suggest time for both Delta 100 and Delta 400 so Gama figures never entered the equation. Besides, I believe I'd have to be waaaay of on my developing time and temp to be off from box speed by 1 2/3's of a stop. Especially when I'm only off by 2/3's stop for the 100 speed Delta. My water is controlled by a mixer and never varies the bath temp and my timer and agitation was exactly the same. The only variable is the shutter speed. I can't believe the old Cumpur, which hasn't seen a CLA in 25 years is running fast. That would mean my 1/125 of a second is acully 1/250 of a second. The Delta 100 test was done at one shutter speed of 1/30 of a second and Delta 40 at one shutter speed of 1/125 of a second only.
I've never once had an old leaf shutter speed-up over time, but I sure have had them slow down. I'm going to be gone for a week, but will certainly be investigating this when I get back home. My reason for this thread/post was to see if anyone else has had this experience with Delta 400 in Perceptol? I have used Perceptol a lot with other films and never expect anywhere near box speed, but almost 2 stops less seems very strange to me since the Delta 100 was only 2/3's less.
 
hi john

sorry to sound like a layman, but why don't you bracket a roll of exposures and develop them all
in your developer and pick when iso you like the best, or .. expose a whole roll with the iso your tests gave you
and see if they "look" ok ? maybe its just one of those things ...

good luck !
john
 
The only other possibility I can think of is that you bumped the aperture down a stop when you moved the shutter speed - on the G-bar front, you should be sitting somewhere in the low-mid 0.6s - right around what Ilford would define as 'normal' dev time - a g-bar of 0.62.
 
John,
That's what I had planned on doing after I got a tested EI. Then I could see how the negatives printed on my system and which "look" I liked best and lock in from there. I most likely won't be using Perceptol with Delta 400, but I thought since I was running the test for Delta 100 and the developing times were the same for both, why not. I just didn't expect that much speed loss with that combination and wondered if anybody else had experienced that much loss. I will more than likely be using Xtol-R or Pyrocat-HDC for higher contrast scenes. Oh, one other thing and I know it's not scientific, but the edge markings on the Delta 400 are very dense and bold compared to the Delta 100 roll. I'm guessing it's not a time/temp or dilution problem as the edge marking are showing up really bold. This whole thing is not a big deal, but curiosity was killing this cat and I wanted to know whether or not I was alone on this one.
 
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