I was asked about this picture in my new guest room, so thought I'd give a quick how-to.
First, find a botanical, or other picture you like. Glue it to a canvas.
Next, tear and collage old papers around it. I chose a background of sheet music with an oval "frame" of roses torn out of old wrapping paper. All are rough, torn edges, different shapes, and glued down with white school glue.
When dry, I clear coated it with water based Polycrylic from Minwax.
I let that dry, then brushed on a weathered crackle finish by McClosky.
After that dried, another coat of Polycrylic went on.
The next day, I wiped on a sepia tinted glaze, let it settle into the cracks made by the weather crackle, and wiped it off.
Weathered crackle finish usually is applied over paint, then a second coat of paint is used over it to create a crackled paint finish.
But, water based clear coat is much like paint without color, and creates the same effect. But this way it is tone on tone, and clear. So, adding the sepia glaze shows off the crackle and ages any paper or canvas you do this over.
Here is a picture I used this technique on years ago for a Romantic Country article. The teapot is a photo copy of one of my original watercolors.
For this one, I glazed over it after it was in a white frame, concentrating the sepia tone heavily in the corners, and also using it on the frame too.
I sincerely hate the look of crackle applied as it is supposed to be used, it is soooooooo fake. But I love it to use in aging a picture. And in aging other things too. The trick, to me, is to keep it tone on tone, to add texture.
Here, I took an old piece of scrolly metal. It was antique, but it was not painted and I didn't want the paint I added to look too new.
So, I painted the piece white, did the crackle, then a clear coat, then the glaze. Over that, I did the hand painted roses.
Same technique was used here on this canvas before painting roses.
Instant age for a brand new painting!