Secrets to making crystal clear gelatin? As I've mentioned in another question, I'm attempting to make a large block of gelatin.  Unfortunately, my first few attempts come out a bit amber in hue, using just water, sugar, gelatin and clear flavoring.

After some research, I found a video on making clear gelatin in which they:


used a different brand of gelatin 
bloomed the gelatin in less liquid than I had
added citric acid
heated it for quite some time


I suspect that they also used a lower gelatin to water ratio.  (I need this quite stiff, as it'll be an unsupported cube about 10 inches (25cm) on each side.)

In looking at their images, I think that there's still a little hue to their solution, but I'm not sure which of the differences are most significant to the process.  Does anyone know?
You might also want to use a higher quality gelatin, like the one used for gelatin art. 
See this one: 
https://gelatinartmarket.com/products/gelatin-powder-280?variant=1455952961