Can I melt the reserve gelatin before adding it?

[RogerHyam]

I've just made my 6th bromo-iodide emulsion. I followed the typical instructions of precipitation, initial ripening, add reserve gelatin, bring it back to temp (50C) and continue ripening for another 10 minutes.

When I add my reserve gelatin the temperature drops. I add it slowly so it doesn't go below 40C then I have to warm the whole thing up to 50C before I start counting the 10 more minutes.

Is there any reason why I can't melt the reserve gelatin at say 40C before adding it? Is there some magic of the gelatin melting in the presence of the crystals or does it really not matter?

I have a water bath (actually a baby bottle warmer) sitting there at the right temperature because I use it to heat the Silver Nitrate. It would just make the whole process a little smoother to pre-melt the reserve just be for adding it.

I thought it worth asking before trying - I don't want to have to bin a batch!

 

[dwross]

No reason not to. A lot of recipes do just that, or simply swell the gelatin in water before addition. However, and it's a big "however." This changes a recipe. You can't easily melt dry gelatin, so you'll need to compensate the additional water by removing it from someplace else. You take less chance on ruining a recipe if you try to take a balanced ratio of water from all the steps. Find a recipe that adds swelled gelatin or melted gelatin to get a feel for the numbers. Also, take notice of your timing. You say that you have to warm the whole thing up before you start counting, but that warm-up time is part of the ripening time of your recipe.

 

[RogerHyam]

No reason not to. A lot of recipes do just that, or simply swell the gelatin in water before addition. However, and it's a big "however." This changes a recipe. You can't easily melt dry gelatin, so you'll need to compensate the additional water by removing it from someplace else. You take less chance on ruining a recipe if you try to take a balanced ratio of water from all the steps. Find a recipe that adds swelled gelatin or melted gelatin to get a feel for the numbers. Also, take notice of your timing. You say that you have to warm the whole thing up before you start counting, but that warm-up time is part of the ripening time of your recipe.

Thanks for this. There shouldn't be a problem with liquid volumes as I already swell the reserve gelatin in a measured amount of water first and have gone through a process of getting the volumes to what I think are correct - well it works for now. It is just a matter of melting the reserve before adding it. I'll keep the total time for ripening the same but it won't now have the temperature dip where I add the cold reserve in. This should have the effect of a slight extension which I've been thinking of adding. A little more speed would be nice.