Help with folding
Vocabulary
- Base
- A base is a point of departure where the most central flaps of the final model have formed. Often the folding starts with a preliminary or elementary base such as the triangle base or the blintz which may become almost anything. Later in the folding process a more detailed base may appear, from which a family of models may be folded.
- Difficulty
- Models are classified according to the amount of expertise required. There is not an exact metric for the difficulty. Valley folds are easy, precision, unusual techniques, many steps, and composite foldes increase the difficulty. At Origami for the blind we apply the levels:
- Really easy.
- Easy.
- Medium.
- Difficult.
- Really difficult.
- Mountain fold
- Fold the paper away from yourself so that you look at a ridge. If you unfold the paper, you can feel the mountain fold as a small bump in the crease line. See also valley fold.
- Valley fold
- Fold the paper towards yourself so that you look at a valley. If you unfold the paper, you can feel the valley fold as a small furrow in the crease line. See also mountain fold.
- Diagonal fold
- A fold line that connects two opposite corners.See the guide to the diagonal fold.
- Fold
- To bend the paper and flatten it in the fold line.
- Crease line
- When folding the paper, a sharp line is formed in the fold, the crease line. Unfolding the paper, you can feel the crease line because the fibres and other material in the paper are broken. On the mountain side you can feel it as a small ridge. On the valley side there is a small furrow, more difficult to feel. The paper never forgets a crease line, and if you bend the paper, it prefers to fold in the existing crease line.
- Mark
- To mark a crease line, fold and unfold the paper.
- Down
- Lying on the table, down is towards from yourself.
- Up
- Lying on the table, up is away from yourself.
- Median fold
- Also called a book fold. A fold across the paper, formed by bringing to opposite edges together. See the guide to median fold.
- Flip
- Refold the paper in an existing crease line. See the guide to flip.
About paper
In origami, the paper is most often square. It may have other shapes such as rectangular like A4 or pentagonal.
The paper has a front side and a back side. Plain paper is the same on the front and back, some paper can be colored on the front and uncolored on the back. Some paper may have a different texture on the front and back. The instructions indicate how the paper should be turned if there is a difference between the front and back.
Paper is usually made from plants, often broken down to cellulose. Glue and starch are added to the pulp for better properties. Dampening the paper and drying it again while folded, will fix the paper in the folded shape. This is exploited in wet folding.
The plant fibres will align in a direction. The paper will bend easier along the fibre direction and more difficult across the fibres. In the highly processed standard paper that is not pronounced, but in some paper the difference makes an important consideration when folding.
Directions
Hold up the paper. It has edges in the top, bottom, to the left, and to the right. It has two sides, one in the front towards you, and one behind.
We use this terminology even when then paper is on the table. If the model has paper in multiple layers, we'll talk about upper and lower layers, and to avoid confusion with the top/bottom direction, we'll avoid using that for layers.
The A-format
Copy paper, A4, is the most widespread paper. Simon Andersen even called it the paper of the people. The A-format has proportions 1 to the squareroot of 2. As a consequence, when you halve the paper the two halves will have the proportions squareroot of 2 to 1 which means it is easy to scale A-models up and down.
A0 is defined as 1 square meter of paper with these proportions. Each larger number is half of the previous size, so A4 is 1/16 of A0.
Copy paper typically weighs 80 gsm, "gramme per square meter". Thus one piece of A4 typically weighs 5 g, that is 1/16th of A0
Make a square from the A-format
- Start with the piece of A-paper.
- Bring a corner and it's short side over along the long side.
- Make the crease start at the corner where the long edge and the short edge meet, and make sure the two edges align.
- The paper still has four edges, one of which is folded, and four corners, with one angle being acute and one obtuse.The folded corner forms a 90 degree triangle, a half square. Turn the paper so that the folded triangle is behind, and rotate the paper so that the acute angle is on the top, and the remaining short edge is towards you.
- Fold the short edge up so that the fold goes through the obtuse corner and the edge in the other side aligns with itself. Call this the second fold.
- Unfold.
- Flip the second fold to the other side, and mark the crease sharply.
- Flip the second fold to the front side, again marking the crease sharply.
- Now carefully rip the paper apart along the crease of the second fold. Start from the edge opposite the obtuse angle of the first fold.
- The resulat is a square with a diagonal crease, and a slip.
This method will work with any reactangle.
How to make a diagonal fold
A diagonal runs between two opposite corners.
- Hold the paper with a corner at the top and another at the bottom.
- Bring the bottom corner up to the top one.
- On each side of the two corners are the two edges of the two layers of paper. Use two fingers at the same time to feel and check that each of the edge pairs align perfectly. Personally, I hold the paper between my thumbs and middle fingers and the index fingers to test the alignment, one on each pair of edges.
- When the two corners and their edges align, fix them between two fingers of one hand. For the next steps, make sure to keep a firm hold.
- The paper still has the two corners in the top end. Bring two fingers, the thumb and the index finger, up from below, one finger on each side of the paper.
- Pinch lightly and slide the two fingers down to the fold to form a sharp crease. Mark a bit to the left and to the right.
- Now you can let go of the two fingers holding the corner in position. Move them down to hold firmly around the folded, sharp crease.
- Pinch lightly near the centre, with the two fingers of the other hand and slide them along the fold, first to one side all the way to the end, forming an acute corner, then to the other side forming another acute angle.
- Re-enforce the crease line to make it sharp.
- The paper is now folded in half diagonally. The shape is an isoscecles triangle with the long edge, the hypotenuse, being folded.
How to make a median fold
The median fold is more popular called a book fold. This is a a fold that forms a crease between the midpoints of two opposige edges.
- Hold the paper with an edge at the top.
- Bring the lower edge to the top one.
- Hold the two edges together between two fingers while the fingers of the other hand check that the edges as well as each pair of corners align perfectly.
- For the next steps, hold the paper firmly with to fingers while aligned precisely.
- With two fingers of the other hand pinch lightly around the paper. Slide them down to the fold.
- Pinch firmly to mark the fold as a sharp crease. Pinch a bit to each side.
- Now you can let go of the two fingers holding the paper formly in position. Let them hold around the sharp edge instead.
- De to fingre på den anden hånd holder om ombukket og føres ud til kanten i den ene side, derefter til den anden side.
- Du har nu halveret papiret på tværs.
Flip
A flip is a fold where you reuse an existing creaseline.
Flip the paper by bending it around the existing creaseline until you feel it break in the creaseline. We may also say that we "fold the paper the other way"; it is, however, important that you don't actually "fold" the paper again as that has a tendency to create a new creaseline next to the real one. >
It is easier to flip the paper over firmly creased lines.