Post-swelling with sugar water (5%) is the last step before drying I assume? About 1 min. with agitation sounds right for VRP?
Post swell
Post swell
i use sorbitol in water with some drops of a wetting agent (like photoflo). Color shift is depending on the concentration of the sorbitol. Drying in Isopropyl alcohol makes a very bright hologram on VRP-M