Wrinkled paper with printing

[randal21]

I am printing a 16x20 image on 17x22 Epson Premium presentation paper and I get wrinkly, kind puffed up sections on part of the printed image. From the back of the paper you can see where it has a few wave. Seems to be consistent on the last 5 prints. Is it a humidity issue? Any help? I print on an Epson 7900.

[bill t.]

You might just need some drying time.  The moist, printed part of the paper is shrinking a bit, but the dry part is not.  The strain at the intersection causes some buckling.  Should go away in 1/2 hour or so, depends on paper and inkload.

[Steve House]

Same thing happened with me receently.  Canson Platine 17x22 with a poster-image with some large areas of pure black under white lettering.  Epson 3880.  There was so much ink being laid down that the paper ballooned up in the middle from the dampness (I think), causing head strikes down the very center of the page starting about 6 inches in from the starting end.  At least there was a line of strikes, transverse slash-like marks parallel to the direction the head moves, down the dead centre of the page, so I think it was due to the paper buckling up in the centre.

[howardm]

Steve,

Did you experiment w/ changing the ink density and/or drying time per pass?

[randal21]

Thanks for the input. One factor initially on this print job was I rushed the drying time and put them in their plastic sleeves probably too soon ... before the 24  or 12 hours drying time I usually allow. Would humidity cause this kind of problem? I have never had to adjust the ink density but will explore this. Would love to find the solution. Will try a 100% rag paper (Somerset Velvet) to see if it effects it too. The buckling was only slightly at the edge where the ink and non printed edge is so it has gotten better but the client is really hawking it over now.

[Steve House]

Steve,

Did you experiment w/ changing the ink density and/or drying time per pass?

Yes, reducing ink density by about 15% minimized the issue.

[bill t.]

Whatever else, about a minute in a dry mount press can flatten just about anything to a plane that would make even Euclid jealous.

[randal21]

Is the ink density on the 7900 under Advanced Media Control and the adjustment is the Color Density slider?  thanks. Will try this first since I don't have access to a dry press.

[bill t.]

A dry mount press is just about a necessity if you are selling prints.  If not to mount, then to flatten.  They're pretty cheap these days.  Unfortunately many of them that turn up on ebay etc are basket cases, although I bought a superb Seal 500TX with a 26x34 platen for a song.

Note that printer profiles are closely linked to specific inkloads and any change in that inkload will trash the value of the profile.  If you find a lighter inkload solves your ripple problem, you should run new profiles with the patches printed at the new inkload setting.

But ripple issues are a pretty poor criteria for easing up on inkload!  That should be only about image quality.  There are a lot of discussions here about how to select an appropriate inkload for a given paper.

You can also press prints between pieces of paper and stiff plates like glass.  I know this works, but it takes some time and I'm not patient enough.

And of course you can also use a clothes iron to flatten prints.  I'm sure somebody here can elaborate.