Artwork Cockling.

[Justintime]

Not so much an ask for help as a "anyone else suffering from this at the moment"?
I'm lucky enough to have a reasonably stable relative humidity in my studio, currently sitting at 45%, which is within the perfect museum range of 40-50%. However the temperature is less controlled. In winter I can regulate it around 20oC but in Summer and particularly recently it has spiked to 28oc for a number of hours each day.
I took a print in a few months ago which I remember being perfectly flat. the customer returned to do a redesign a month or so later and I noticed that the paper had a very mild cockle to it. Now it's finally time to mount it, it has a more much obvious cockling going on.
After a long chat with Google AI I have learned much more about the reasons and causes of this development, much of which I don't think are discussed enough in our circles. I'm going to assume that the information and remedial advice is correct, but also double check it with a few top tier framing experts before undertaking the remedial work suggested.
Anyone else suffering unexplained cockling?

[vintage frames]

That sounds really interesting.
Looking forward to hearing how you're going to deal with it.

As a further comment which will be of no help whatsoever,
the cocking effect appears unique to only modern production papers.
Early cotton rag or hemp papers seem to get along quite happily in any sort of climate.

It might be something in the way they sort of breathe by soaking up the humidity and then drying out again as the climate changes.
A bit like a lime mortar building.

[Justintime]

It is partly that. In this case the print image on the paper is an inkjet UV curing process, so it's slightly plasticised. Part of the problem sounds to be that as the RH dropped (when it entered my drawer) the outsides of the print dried out quicker than the reverse centre of the print (as the plasticised image front cannot "breathe", only the reverse of the paper ) which initially caused the minor cockling. Followed by a steady rise in temperature, up to 28oc, this exacerbated the problem causing more extreme cockling to develop. Contrary to what I have heard in the past, AI says that it is permanently reversible, but will not reverse over time once it is sealed in a frame. I'm told it has to be forcibly reversed, by for example 20 minutes under cold vacuum, immediately followed by up to 72 hours under weighted glass, preferably plate/toughened. This will apparently force the fibres back to their original length and it should remain flat if framed straight after, unless of course it is subjected to extreme heat or humidity change again, but once framed the effects will take much longer. The processes I mentioned have been greatly simplified for ease of reading this!

[vintage frames]

Well, you could try it out. You've got a vacuum press.
Pop a few sealed bags of ice in with it, if its a cold vacuum needed, then go for the 72 hour press.
I can't see what damage it could do.

[Justintime]

Like a cold pressed coffee??