I have been asked many times by my customers and other friends, how can they tighten their canvas.
First of all, a good quality canvas is always 100% cotton. I'm referring to original paintings.... hand-painted... A printed canvas is a blend of polyester and cotton...usually a 65% - 35% ratio.
Cotton as our cotton clothes, it becomes saggy - loosens up over time.... this happens due to the temperature change.... when it sags - gets loose, it could distort the image on the canvas ...
So, before you get all panicked and run off to the framer try a simple, safe, fast method... This is what I also do... This is what the framer will do... At least the first thing he will try to do...
Turn the canvas over, and place the front on a clean surface. Make sure there is no dust on the back.
Lightly spray water onto the back. Everywhere on the back... make sure the edges are wet. You don't have to soak it.
Instead of spraying water, you could use a damp cloth and gently wipe the back of the painting. Again, everywhere... all the way to the edges. If there are braces in the middle, wipe under them... Do NOT be afraid.. Nothing will happen to the painting. It's only water.
Wait until it dries. After few minutes 15-20 min max (depending on how much water you used) the canvas is ready to be hung again. Some artists will use a hairdryer to dry the canvas. You don't have to do this. It will dry on itself. I strongly suggest that you do not use a hairdryer.
And that's it.. This is very easy and very safe. This is exactly what I do, every time I am ready to paint. A canvas should be tight as a drum.
If you have any questions or want some advice, please do not hesitate to contact me. I'll be glad to help you