Neopan 400 + Xtol 1:3 -- speed bump? -- confused!

[cinefane]

A couple of months ago, I settled on Neopan 400 and Xtol as my chosen film/dev combo. I've owned my Mamiya C220 for about as long, with which I've taken all my photos.

I'd been frustrated with the lack of sharpness in my prints. I'd made sure I was doing everything possible to keep the pictures sharp -- aligned my focussing screen, found the sharpest stop, aligned the enlarger, etc... -- but my prints were always a little undefined for my liking. I blamed the lens/the film size/the camera/the enlarger lens but I read the other day that using Xtol at 1:1 might be causing my woes.

I shot a test roll today and developed it using Xtol at 1:3.

I'm very pleased with the results. I haven't done any side by side comparisons yet but the test pictures do seem a lot sharper than those I've developed with Xtol at 1:1.

The thing is, I'm a bit confused. To get me in the right direction, I got the timings from The Massive Dev Chart. My dev time using Xtol at 1:1 is similar to their timing and gives me box speed. But developing the test roll with Xtol at 1:3, my gray card shots seem to suggest I've gotten a speed bump of two stops! Can that be right? My new dev time was twice as long as it was with the 1:1 dilution. Is that the cause? But, if that's so, why doesn't the neg look overcooked? Judging by the contrast of this first test roll, I'd have thought it needed a little longer in the soup.

Why the speed increase of two stops? I'm confused.

 

[cinefane]

Why is that? Does the sodium sulfite inhibit the developer? Aren't they in the same proportion?

 

[Wolfgang Moersch]

The proportion (dev. agents : sulfite) doesn´t change, but the amount of sulfite in your solution. With 1+1 dilution you have enough sulfite to act as solvent agent, with 1+3 not.

 

[Tom Stanworth]

More acutance, yes, but not a TWO STOP speed gain!!! Maybe 1/3 stop over 1+1 if you are lucky. I shoot the same film at box speed in 1+1 and 1+3. No real difference to my eyes. If I get a hair more speed at 1+3 I have not bothered to notice because 400 works just fine. I certainly dont get negs two stops overexposed - no way! Thats EI 1600 from 400! I suspect an issue elsewhere. Try shooting the same ubject at the same exposure on the same roll and then cut the roll in half and dev the two halves at 1+1 and 1+3.

A substantial increase in dev time with a big change in dilution is normal. You are going from 1/2 Xtol to 1/4 of the solution is Xtol - half as much. This would normally result in an increased dev time of about 1.6-1.7 for many people, depending on agitation, or 1.4 or so with rotary I have been led to believe. I find that with me, I need to get to about 1.7 to 1.8X when I half the concentration, so you are not far out. If you have over developed a touch it would not account for two stops. Not a chance IMO.

 

[Bruce Watson]

The thing is, I'm a bit confused. To get me in the right direction, I got the timings from The Massive Dev Chart. My dev time using Xtol at 1:1 is similar to their timing and gives me box speed. But developing the test roll with Xtol at 1:3, my gray card shots seem to suggest I've gotten a speed bump of two stops! Can that be right?

No, it can't be right. For reference I use 5x4 TMY-2 in XTOL 1:3. Having done fairly rigorous Zone System testing I find an EI of 540, or 1/3 stop over box speed. This is the same result I got with Tri-X before switching to TMY-2.

There is little you could do to turn an ISO 400 film into an ISO 1600 film. If there were I'd want to know for sure!

My new dev time was twice as long as it was with the 1:1 dilution. Is that the cause?

But, if that's so, why doesn't the neg look overcooked? Judging by the contrast of this first test roll, I'd have thought it needed a little longer in the soup.

Why the speed increase of two stops? I'm confused.

The time being twice as long is due to the fact that the dilution is twice as big. I'm assuming you are using a small tank and inversion agitation, yes?

It works like this. For continuous agitation (think rotary processing) developer time varies as the square root of dilution. IOW, when you double dilution you multiply your development time by sqrt(2).

With intermittent agitation like a small tank, the rule of thumb is doubling dilution doubles development time. Some will want a little less time and some a little more -- it all depends on how vigorous and how often you apply your agitation technique.

With stand and semi-stand, all bets are off. This is where individual developer's "personality" comes through. Some do this work better then others so times vary widely. The rule of thumb becomes "test and see."

 

[Tom Stanworth]

As Bruce says, compensation for dilution varies a lot. I am however amazed how many users claim to multiply by 1.4 when halving the concentration of dev as this is miles out in my experience. Close to double is much more like it with a small tank. This is also in line with Patersons time adjustments from 1+9 to 1+19.

This dicussion came up somewhere else and much more knowledgeable people than me explained that is varies enormously between developers so going from 1+1 to 1+3 with Xtol and with D76 could result in rather different adjustment factors.

 

[Venchka]

Use GOOGLE. Ask GOOGLE to find the unofficial Xtol pages. Scroll down until you find a link to the German Kodak PDF technical file for Xtol. Download it. You will find pages and pages of dilution rates & times & films. Neopan 400 is listed for each dilution rate.

I use Xtol 1:3 for everything. My very unscientific experience suggests that Xtol 1:3 and continuous agitation in Jobo tanks for 10 minutes works for several different films. I do expose at less than box speed.

 

[Richard Jepsen]

Perhaps a max .5 stop increase but a 2 stop increase is not correct. The increased shadow detail is the result of developer exhausting in the highlights while chewing away in the low areas. Agree with the advice to find the German published XTOL developing PDF. I believe the data is the same as Kodak's published times when XTOL came out about 1995. XTOL is a flexible product and does increase sharpness on dilution.

 

[waynecrider]

http://www.covingtoninnovations.com/xtol/

It's down under the older recommendations header.

 

[cinefane]

I'm going to shoot another test roll. I reckon I must have ballsed the metering up somehow.

 

[Tim Gray]

Why don't you shoot a roll with a bunch of test exposures doubled on the first half and the second half of the roll, then cut it in two in the darkroom and dev it both ways? Take all the variables out but the developing...

 

[Joerg Bergs]

I use a lot of TriX (TX400). In XTOL 1+1 the film have its box-speed. In a dilution of 1+3 I use the TriX at 800ASA!
I translate my german XTOL Text into a english version. You find it here: http://www.joerg-bergs.de/40.html?&L=1

 

[cinefane]

I shot a couple of test rolls and it looks like my previous result of 1600 was due to cack handed note taking. However, I did get a significant increase over the box speed. It looks like I'll be shooting Neopan 400 with an EI of 800 from now on.