Progress on XTOL-concentrate

[albada]

Anyone have accurate numbers for the weight of 6 ml of HC110 concentrate ?

I know you're mostly joking, but I went ahead weighed a 6 ml syringe empty and full of HC110, and subtracted, which gave: 7.2 g.
But the ml and weight numbers printed on the side of the bottle work out to 6.3 g.
So something is wrong.

Mark

[albada]

Never measure by volume.

As I learned the hard way.

And I'll repeat this until you're tired of hearing it:
An electronic scale from amazon only costs $15. That's the cost of just 3 rolls of film. There's no excuse not to have one.

Mark

[Murray Kelly]

50mg of phenidone is 1ml of a 5% solution in alcohol (or anything).

Do you have any trouble measuring the

Phenidone ......................... 0.05 g

even times three that's pretty small. Where I buy my Phenidone they indcate they will not measure out less than .5

I don't mix much from scratch....just a question.

Thanks

[MattKing]

I know you're mostly joking, but I went ahead weighed a 6 ml syringe empty and full of HC110, and subtracted, which gave: 7.2 g.
But the ml and weight numbers printed on the side of the bottle work out to 6.3 g.
So something is wrong.

Mark

I don't see any weight numbers on the photo of an HC110 bottle I have in hand. Any chance you are confusing fluid ounces with weight ounces?

I expect that the best way to do this would be to weigh a full bottle of HC110, then weigh an empty one and to that subtraction. Then divide the result by 473 to get the weight of each ml of concentrate. Finally, multiply that weight by 6.

I'll have to see if I have full and empty bottles in my storage area.

[Photo Engineer]

Careful Matt. Mass assembly of plastic bottles does not mean uniform weight. They may vary by several grams.

PE

[MattKing]

Careful Matt. Mass assembly of plastic bottles does not mean uniform weight. They may vary by several grams.

PE

Thanks PE.

This means, sadly that I would have to weigh the bottle before I start using it, and then the same bottle when I am finished.

Darn - that means waiting a long time.

Well at least it isn't Photo-flo

[albada]

Any chance you are confusing fluid ounces with weight ounces?

Uh oh... (Mark looks up "Fluid Ounce" in Wikipedia). Hey! A fluid ounce is a measure of volume, not weight. Grrr!! That explains the odd result from the numbers on the bottle. Knowing this, the syringe-measurement that says 6 ml of HC110 weighs 7.2 g is probably correct. I expect you to weigh out your HC110 from now on.

Back to D316.
I said in an earlier posting that toes are slightly softer but hard to tell. I saw an unusually soft toe with Delta 400, so I'm running strips on it. The curves:



Red is Xtol; black is D316. Green is D316 but the half of the strip with more flare, and it serves as a second opinion of the toe. That toe is enough longer that it concerns me. D316's grain is finer, but would this longer toe cause significantly darker shadows than Xtol?

Mark

[albada]

I realized that I could also measure the higher-flare half of the Xtol strip. Here are the Xtol-D316 curve-pairs. The left graph is with minimal flare; the right graph is with more flare but still shows the shape of the two toes.



This gives you two comparisons of the toes of Xtol versus D316.

Mark Overton

[albada]

I made two discoveries this weekend.

1. The toe in Delta 400 can be shortened to match Xtol by reducing ascorbic acid (AA) to 3.7 g or lower. D316 uses 4.5 g, and I tested 3.0, 3.5, 3.7 and 4.0 g this weekend. At 3.7 g, sodium metaborate must be reduced to about 1.7 g. This raises pH some to compensate for loss of activity due to reduced AA. Grain is still at least as good as Xtol. BTW, my test-strips contain two frames each, so I can measure two toes in each test, giving me more confidence that I didn't see an anomaly.

2. Even with reduced buffering due to reduced alkali and acid above, highlights and shoulder were identical. I finally realized why: The shoulder is caused by the limited diffusion-rate of the gelatin. I designed my developer to have a higher devtime-to-phenidone ratio than Xtol. As a result, my dev needs a lower diffusion-rate than Xtol (which I never thought about). So it hits the diffusion-limit at a higher density. Hence the higher shoulder. (PE, please correct me if I'm off in the weeds here).
This gives me an idea of how to make a developer that's good for pushing: Reduce that ratio so much that even midtones sag. That will give the toe-area time to develop more while taming overall contrast.

3. I'm happy because I killed the gopher that was tearing up my back yard. Oh, this is off-topic...

Mark Overton

[Gerald C Koch]

The specific gravity of HC-110 is 1.24 from the MSDS. So 6 ml should weight 7.44 grams.