When I create a monoprint on a Gelli Plate I mat the finished print leaving a 3/4 inch border around all four edges. However, with this print, I trimmed the paper right to the edge of the image and therefore couldn't mat the print without losing a good deal of the image area.
Instead, I chose to glue the print to a cradle board and build from there. I gessoed the cradle board (8" x 8"), then adhered the print using Golden's Soft Gel Gloss. I spread the gel thinly over the entire board, placed the image on top, then, wth a piece of waxed paper on top of the image to protect it, I worked a brayer back and forth gently to ensure good adhesion.
I then put low tack painters tape over the entire image to protect it and then smoothly applied Golden's Light Molding Paste to create a raised border. (Remove tape before paste dries.).
Once the paste dried I washed Golden's new QOR Watercolors over the border to tone the color. I used a couple of different yellows and a soft blue. The watercolor tended to soak into the paste. Next, I taped some vertical lines and used a sponge to dab on strips of blue acrylic in the upper right and green acrylic in the lower left of the border.
Finally, I used a 2B pencil to create a tree line and some shapes on the horizon. I dabbed some acrylic highlight colors into the tree foliage and the horizon shapes…and I considered it a day!
I haven't varnished this, but you could. Just carefully apply a thin layer of gel medium over the entire surface (working gently so you don't disturb the graphite), then, when the gel is dry, varnish.