Now I'm interested.
There are two things here:
1. You said you successfully transfer an image on the smooth side. Mind sharing that?
2. To make pattern, the fabricator use hot mold and press against the foam. Heat will close the pores, therefore ink/dye will not stick to it.
What I have in mind (still in theory):
a. Sanding it lightly (but it has the risk of ruining the pattern)
b. cover it with paper/paper mache (I don't know how conformable paper to the pattern)
c. do fabric printing, and glue it to the patterned foam, and use pressure so the fabric is conformed with the pattern.
d. try to ruin the foam surface chemically (acetone/porcelain cleaner/acid?) lightly and wash it quickly.
sure the methods I have had success w/ on the smooth side
are,
the Acetate Transfer Method:
this method requires the Printout to be Either Laser printed or
Photocopied, because its all about the Toner, Inkjet doesnt use toner
to do this take your image lay it printed side down on your surface
the take some acetone pour a some on a paper towel and rub it onto the paper where the pattern is, not to much acetone as you dont want to disolve the toner completely just keep going @ it. when you lift the sheet you will see
a reproduction of your rubbing on the foam
another method I found today, the simplest of all works w/ a standard Inkjet
and Plain ole' water, moisten the surface and moisten the image lay it printed side down and burnish the back of the image, IE take something like a back of a spoon or a bone folder or a credit card and rubb it along the image/lines w/ a little bit of pressure you should see the ink transfer to the foam,
those are the 2 simplest methods I've found most are variations along those lines using various chemicals or whatnot.
writing on the textured side is no problem IE sharpie or other marker but that rubber coating and maybe the texture seem to repel the ink from transferring, so I've just been trying to eliminate a step when copying my template to the foam, and as for sanding the texture well again defeats the purpose
so projects call for incorporating that texture. some people say I'm overthinking things and complicating it. I just have extra free time and am trying to simplify future projects