Trim the periphery of the work neatly, and use a piece of cardboard larger than the area of the work and thicker than 100g, a piece of dark tissue paper, colored paper with edges, watering can, paste or glue stick.
step
1. Cut the cardboard into base paper, which is larger than the back of the work and as wide as 5cm or more.
2. Cut the dark cotton paper into strips with a width of about 1 cm, which is slightly longer than the edge of the work.
3. Put the work face down and spray the back of the work with a watering can, not too much water, just evenly.
4. Brush a paste about 2 cm wide around the sprayed work, stick the 0.5 cm part of the thin paper strip, and then spread the pasted paper strip with paste.
5. Spray the cut cardboard wet, then cover it on the work and press it tightly. Put 0.5 cm wide paste around the cardboard, turn it over and stick it on the board.
6. Cut the colored paper with the edge, and the width is the width from the border of the work to the edge of the cardboard. Spray the cut colored paper wet, brush the whole back with paste, and stick it around the work, paying attention to leaving a narrow gap with the work.
7. When it is completely dry, cut the cardboard with a ruler and a knife.