NiallCampbell wrote:I normally work with my colours 1:1 with flow improver. I'm assuming I need a good few more drops of glaze medium to get the thin consistency?
I'm assuming by "flow improver" you mean "water mixed with a surfactant" (10:1 water and Flo-Aid mix, "wet water"/water+Jet Dry rinse agent, etc.) or some pre-mixed, flow-enhanced acrylic medium. Pure flow improver for half of a mix would give you runny, colored soap suds.
I know there are products billed as glaze mediums out there, but I've yet to bother with them. The point in making a glaze is simply to drop the paint's opacity without losing pigment dispersion/adhesion or changing the consistency, overmuch (otherwise, you'd just water it down a lot). To that end, all you would really need is acrylic matte medium. Increasing the volume of medium drops the opacity, proportionately, as the amount of pigment remains constant. The result could then be diluted as normal and should behave similarly to your usual paint (would be identical, if your chosen paint has the same consistency as the matte medium, which is rarely the case).
I usually end up tweaking my mixes further, so I added a few extras into my DIY glaze medium to cut out extra steps. I forget the exact proportions, but it is roughly 70% matte medium, 15% drying retarder, and 15% water/Flo-Aid mix. Used neat, it makes for a nice glaze when mixed with my old Citadel/VGC paints. Sometimes I'll dilute it a
little further on the palette (already thinner than the paint, but not as thin as what you usually use). If I add significantly more water (closer to 1:1 water and paint/medium mix), it makes for nice ad hoc washes.