This is what the foundry typically looks like as it is warming up. There is a deep orange glow to some of the metal but nothing exciting. Once it gets up to temperature the glow can even be seen slightly when it is not dark.
These shots are with air being forced over the coals. We tried to turn the air pressure up to the point where we got flames like this then back it off a bit until the flames just barely died.
These shots are a lot more dramatic because of the slight time lag tracing out the path of each ember. Really this is safer then it looks. We took each shot with embers flying off the foundry right as we dumped in a blast of high-pressure air onto the coals. We typically did this a few times right before pouring in order to get the temperature as high as we could. We had to spike the pressure as our air compressor was a little underpowered for the job and could not run continuously.
I think this last picture on the right is my favorite.