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Has anyone heard the term "Working Frame" before? Appaerantly it is a frame the artist use to display things and then remove the artworks and reuse it by sliding the old work out and sliding the new one in...
I’ve heard of “working frames”, but more commonly “working mats”.
Artist’s sometimes use such a mat to hide the edges of the paper on which they often slop paints or pigments. It seems to give them an idea of how their work is going to look in real life i.e. cropped.