Reducing risk of warping in large panels painted with egg tempera

I would not suggest having exposed glue on the back of the panel. It is the most reactive material used in easel painting and could respond severely to changes in RH. It is also very attractive to bugs when it does not contain a filler or pigment. Possibly you could paint over the dried final glue coat with an alkyd paint to seal in the glue but this would still leave an extremely thick and reactive layer below the surface. I know of a number of tempera painters who coat the back of their panels with an acrylic dispersion or alkyd paint layer to minimize water absorption but this would not serve exactly the same function that the gesso on the reverse does for you. If it were me, I would prepare a test panel with alkyd already dried on the back and apply the gesso to the front. Let it dry face up and not against a wall like you probably do when you gesso both sides. Check for warping after the whole is dry. If not, go with this procedure. If the panel does warp try doing the same but paint a layer of acrylic dispersion paint or what people call acrylic gesso on the back after you finish gessoing the front and before leaving the panel to dry over night. Hopefully the water in the acrylic dispersion will equalize the tension. If this does not work you should probably go back to your original laborious procedure. Others on the forum may be able to weigh in on this. Brian Baade

Thank you for answering this question. I will try out the test panel as you suggest. I may also try applying gesso coats on both sides but use a thinner formula (slightly more size to gesso – the recipes in various texts seem to allow some flexibility in how much whiting is used) and hope this will help with a smoother application, but this will obviously mean more coats of gesso to cover the panel sufficiently.