Emulsion staying liquid

[Isaacm9]

Just experimented with my first batch of Mark Osterman’s silver gelatin emulsion, I was able to get a few dry plates out of it but after heating it up for a third time, it is staying liquid and not returning to solid, even when placed in the refrigerator. I’ve seen people say this can happen with old gelatin, but mine is a new bottle from B&H!

Does anyone know what this could be? I’m a newbie to emulsion making so I’m sure it’s probably something I did, but I couldn’t find a definitive answer. Thanks!

 

[koraks]

How much time was there between initially making the emulsion and the point where it won't set anymore?
The issue with gelatin is that, basically, it rots. Bacteria get to it and start feeding off the proteins. The result is goo.

 

[Isaacm9]

How much time was there between initially making the emulsion and the point where it won't set anymore?
The issue with gelatin is that, basically, it rots. Bacteria get to it and start feeding off the proteins. The result is goo.

It was only a month, it’s definitely not rotted and it only happened after I heated it back up! I think the problem may have been my temperature being too high?

 

[koraks]

it only happened after I heated it back up

Okay, that's odd. When gelatin rots, it turns to goo without having to be heated, first. But it's conceivable that it was borderline decayed and just won't set anymore, even though it was still gelled when you started out with it.
Btw, a month is quite a long time. Have you kept food in a fridge for a month? Did that work? Your gelatin emulsion is basically just pudding, keep that in mind.

I think the problem may have been my temperature being too high?

How hot was it? Gelatin usually gels just fine even if you heat it to 60-70C (although this will likely increase the level of fog in your silver halide emulsion).

 

[mshchem]

It's been close to 40 years since I made emulsion. Didn't see this.

 

[ezphotolessons]

Just experimented with my first batch of Mark Osterman’s silver gelatin emulsion, I was able to get a few dry plates out of it but after heating it up for a third time, it is staying liquid and not returning to solid, even when placed in the refrigerator. I’ve seen people say this can happen with old gelatin, but mine is a new bottle from B&H!

Does anyone know what this could be? I’m a newbie to emulsion making so I’m sure it’s probably something I did, but I couldn’t find a definitive answer. Thanks!

Are you heating the whole amount of emulsion up every time, or removing a smaller amount to melt? 3xcessive melting affects the emulsion as a whole. I am not sure about the gelatin rotting suggestion, I have used very old emulsion many times, both home made and store bought and it was fine.

Are you using "lab grade hard bloom" or food grade gelatin ? Have you considered warming a small amount and adding a little more gelatin to see what happens?

 

[Isaacm9]

Are you heating the whole amount of emulsion up every time, or removing a smaller amount to melt? 3xcessive melting affects the emulsion as a whole. I am not sure about the gelatin rotting suggestion, I have used very old emulsion many times, both home made and store bought and it was fine.

Are you using "lab grade hard bloom" or food grade gelatin ? Have you considered warming a small amount and adding a little more gelatin to see what happens?

This was the only time i'd ever heated it up after the initial making of it. I'm using photo grade gelatin, following the recipe closely! I didn't try adding more gelatin, though i suppose I could.