I have just begun painting with oils and am used to watercolor painting. In watercolor painting, if you finish a painting and are not totally satisfied with it, you can crop it to a smaller size, and other than cutting it, there is not much else you need to do. I can understand how you might be able to crop oil paints on canvas, but am wondering about how, and whether you would have to take any kind of special care if you cut down a painting that you had painted on some type of board (using oil paint or even acrylic). Would you then have to go back and treat the edges somehow since you had to cut through the paint film? The frame (if you framed it) would hide the ragged edges of the paint, but I am still wondering if you would have to finish off the edges somehow. Would you sand them and then later the varnish would finish it off? Acrylics aren't varnished, would you have to use some type of gel medium to finish it off?
When I have cropped a canvas panel painted with oils, I place it on the table saw & run it through.
Use a sharp finish blade & it will be a smooth cut. This is the key..
So far I have not sealed them as the glue that held the canvas to the board seems to hold the edges down...
J.b., thanks for answering. I haven't done much painting in oil, but someday I would like to try plein aire painting and have the feeling that trying to compose exactly what I want for a composition may not work real easily. I figured that if watercolor artist's crop their paintings then oil painters probably figured out a way to crop theirs too. However, I was really wondering about the edges on boards or canvas covered panels, which you have just answered.
I pay attention to my sides in my miniature acrylic paintings, as they are done on either hardboard panel or Ampersand clayboard, cut to a 2 1/2" x 3 1/2" up to 3" x 4". I sand & gesso the edges, paint them in a solid colour that suits the background of the work, & yes, I varnish my acrylics with gloss varnish, including the sides.
My framer then mounts them on black painted oak wood frames, so the actual painting is sitting in the middle of the black frame, & the edges of the board are visible.
You can see one of my framed minis here: http://www.seasideart.com/ProductDetails.aspx?id=5510 (Click on the "Art and Frame" link.)
I've cropped work on board before, & have always sanded, gessoed, painted & varnished the edges before framing, even though the edges are not visible in most frames. I think I read somewhere that it's important to seal the edges of any type of panel.
Nature knows no borders
Judyl40, thank you. This is the kind of information that I have been looking for. Thank you so much for sharing.
If you were painting on canvas or linen not mounted on a board there is a very easy way to adjust your composition or crop if you need to...
So far, I haven't been painting on canvas because of the price and fragility of the surface. However, I am always open to learning how to fix something ahead of time because the need for that type of information seems to inevitably come up. Thanks for sharing.
What you've mentioned is exactly what I have to deal with. I have a 9 by 16 inch stretched canvas and I need to keep everything from the upper left corner to about 3/4 of the way to the right side and also 3/4 of the way to the bottom of the canvas. I have never cut a stretched canvas to crop it before and am hoping you can suggest a way to do it, because if I can this will be the best oil painting I've ever done. Thank you very much.
You don't cut stretched canvas. You would undo the staples, and re-stretch it on a smaller stretcher frame. I guess, if you don want any of the painting to show on the back of the stretcher you could paint that overhang white.
I work a lot on Masonite ( hardboard ) If I need to crop it, I just cut it on my saw and that's it. The few times I have used canvas panels and wanted to crop the work, I just used a matt knife. Later I seal the back with acrylic varnish and I paint the edges as well. I just don't like that open cardboard backing on the painting. If they have a big logo on there, I have painted the back with grey acrylic paint.
I keep some canvas panels in my trunk because I have gone out to paint and forgot to bring a hardboard panel. Plus I often paint with groups and have bailed out others as well and they have done that for me too.