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# Thread: Spursinn HCD. 51200 ISO developer.

1. I think we will only get a MSDS if they bring it over to the US for sale, I am not sure of what the equivalent would be for Germany or the UK, but I think there maybe be something of that sort to outline whatever is in their solution. Two bath developers are nothing new and many work quite well, but so far this one seems to be lots of hype that I hope it lives up to.

2. Originally Posted by Photo Engineer
To get the true speed of a film, draw a straight line extended out from the B+F to infinity. This is done using the H&D curve. Then, note the deviation point of that H&D curve from the straight line. This is the inflection point of the emulsion and is the maximum point at which this emulsion can register an image. It is called "threshold speed".

Translate that into speed using standard methods and you get the max speed of that product.

Now, create a developer that swings the curve on that single point and you have a developer than can approach that speed point. At this time, the maximum threshold speed ever achieved is 25,000. These materials were never sold.
Thanks for this explanation---it's something I've long wondered about. If I understand correctly, this is basically the speed that follows from the principle that the most you can do is develop to completion, right?

I imagine the threshold speeds of common materials (like the one that starts with a T and ends with an X400) must be known in the industry---is there any way for us outsiders to find out what they are?

-NT

3. You can find out the minimum exposure it takes to produce a detectable change on the negative (first exposure that provides density above film base density) in your camera + developing combination (whether push or not) using a densitometer.

4. Dan is correct.

Using a step scale, such as a Macbeth Color Checker, you can expose correctly, and then figure out the threshold speed just by looking at the curve from this. Then, assuming ISO 400 from the straight line, you can guesstimate the maximum speed by the method Dan has described. Just look at the first detectable image and then measure the number of stops that this takes place at, vs the mid scale.

This is the threshold speed and is the max that can be obtained from that film by any means.

PE

5. ## trial packs of HCD-2 and HCD-2 and -S

are currently on offer at http://www.keyphoto.com/shop/ and both Keyphoto and AG photographic in the K will mail order Spursinn photo chemistry.

6. Pope Benedict used it with Leica Ia and he says he saw god in deep space , such a good developer I will use it to 100 000 asa to catch the monkeys tails when they are jumping tree to tree at night

7. Originally Posted by Photo Engineer

Unless the MSDS is published, it will remain to be seen if this new developer works well.

PE
MSDS is so 15 minutes ago...

MSDS is on it's way to the history pages. SDS, Standardized Data Sheets, are the new hot thing.

Difference? Many other countries, including the EU, have bought into it, and it will simplify shipping chemicals in commerce between countries.

MSDS will be gone by December 1,2015, with supply line phase out by June 1, 2016.

All part of the GHS Globally Harmonized System.

So we may still be able to get info.

Sent from my iPad using Tapatalk HD

8. The actual manufacturer of that HDC-2 new meanwhile outed themselves. It is, not surprisingly, SPUR.

They now stated that the speed of up to EV 51.2000 to be gained, as stated by Spürsinn would be exaggerated.
It rather would be ISO (this case) 1000 for Tri-X, whereas with a product they market themselves they gain ISO 1600.

But in an interview last year one of the owners/researchers behind Spur stated that HDC-2 new indeed would gain that speed of 51.200 for Tri-X for practical use under extreme lighting conditiions.

Maybe those two statements (both published by Spur in a díspute with Spürsinn) are a case of wording I do not quite understand. But nevertheless such statements are frustrating.

9. Originally Posted by AgX
The actual manufacturer of that HDC-2 new meanwhile outed themselves. It is, not surprisingly, SPUR.
Does SPUR manufacture at all? It is my impression they do the research part but the manufacture is handed over to a third party.

10. I have no information about a third party being involved.

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