Spiral images may elicit memories of childhood pinwheels and colourful kaleidoscopic images. Painting spirals from scratch requires a steady hand and the ability to draw perfect circles. GIMP, a free image-editing program, enables computer users to produce perfect spirals without ever touching a digital paintbrush. Simply activate GIMP's "IWarp" filter, adjust a few controls and click your way to perfect spirals in minutes.
Launch GIMP, and Press "Ctrl" and "N" simultaneously to open the "Create a New Image" window. Type 500 in the "Width" text box and 500 in the "Height" text box. Click "OK" to close the window. The main canvas appears in a new window. Its canvas size is 500 x 500 pixels.
Find the colour box located near the centre of GIMP's toolbox. The colour box displays two overlapping rectangles. Click the top rectangle, and then click one of the colours that you see inside the "Change Foreground Color" window that opens. Click "OK" to close that window.
Return to the toolbox. Click the "Bucket Fill" tool, and then click the canvas. GIMP fills the canvas with your selected colour. Go back to the toolbox and click the top rectangle in the colour box again to open the "Change Foreground Color" window. Click another colour in that window, and then click "OK" to close the window and return to the canvas.
Click the "Rectangle" tool located in the toolbox, and then draw a rectangle at the bottom of the canvas. Draw the rectangle so that it divides the canvas evenly in half vertically. Click the "Bucket Fill" tool, and then click anywhere inside the rectangle you drew on the canvas. GIMP fills the rectangle with that colour. The canvas now consists of two rectangles. The rectangle on top is the first colour you selected. The rectangle on the bottom is the second colour.
Click "Filters" to open a drop-down menu. Click "Distorts," and then click "IWarp" to open the IWarp window. A small preview of your image appears on the left side of the window. Slider controls appear on the right.
Click the "Deform Radius" slider, hold down your left mouse button and drag the slider so that the value in the box next to the slider reads "150." Drag the "Deform Amount" slider until its value reads "0.20."
Click "Swirl CCW" to select that option, and then click "Bilinear" to check that option if it is not checked. Click the centre of the preview image on the left side of the window. The image will warp by a small amount. Continue clicking the same point. As you do, a spiral begins to form. Its arms consist of the two colours you selected for the image.
Click "OK" when you are satisfied with the spiral. The "IWarp" window closes and applies your changes to the real image on the canvas.
The "Deform Amount" setting controls the size of the arms in the spiral. That setting is 0.20 in this example. Increase the value to create larger spiral arms. You can also experiment with the "Deform Radius" setting. Changing its value changes the spiral's shape. By choosing different colours and experimenting with the two slider controls, you can create a wide variety of unique spiral patterns. To change the size of your spiral, click "Image," and then click "Scale Image" to open the "Scale Image" window. "Width" and "Height" text boxes appear in the window. Click the drop-down on the right side of those text boxes and click "Percent." Type a number such as 50 in the "Width" text box and press "Enter." GIMP applies the same value to the "Height" text box. Click "Scale" to scale the image to 50 per cent. Typing different values in the "Width" text box scales the spiral by the amount entered. Click "Swirl CW" to make a spiral with a clockwise swirl.