correcting a bowed canvas board

[Gillthepainter]

I have a linen canvas board 60cms x 60cms.
And this brand has developed a slight concave curve to it. The usual artist painted cross on the back doesn't correct it, and never has. Nor does weighing it down to correct it, as this never seems permanent.

I can only think of 2 things: cut a cross stretcher on my Morso and woodglue it to the back.
Or frame it, putting a hard backing board in to push it into place, but this increases the weight of the painting.

How do you normally correct this when it comes into your shop for framing.

[JFeig]

without the intervention of an art conservator, they are not normally correctable as the paper board backing has warped due to water. An art conservator might re-humidify the paper board and place it in a flat press for a long period of time.

[prospero]

This type of canvas-faced board was never intended for 'finished' artwork. More for quick sketches
done in the field. They are cheap and convenient and easy to transport. They do tend to warp, but
this not really a problem until you get to larger sizes. You might be able to flatten it by gluing it to
a wooden backing frame but you would basically end up with variant of a stretched canvas.

This is why loose canvas on stretcher bars were invented.

[Gillthepainter]

Indeedy.
They are convenient, until they are not. I shall fashion a backing frame to see if I can fix it, but will try to press it straight first before applying the wood.

Thank you.