Satin is a shimmery fabric often used for fancy gowns, sheets or rich-looking curtains. You can make a background that looks like satin using several of the popular image-editing software programs, including GIMP. GIMP is an open-source, free image editing program that runs on Windows, the Mac OS and Linux. There are a few steps involved in making a satin background using colours of your choice.
Run GIMP and create a new file by clicking on "New" in the "File" menu. Set the size of your image to whatever you desire, which is usually determined by where you will be using it. For example, if you want the image to be a desktop background, you need to set it to the dimensions of your screen resolution.
Click on the "Filters" menu and then click on "Patterns" and a side menu will pop up. Choose "Sinus" and the Sinus pattern dialogue box will appear.
Choose the "Colors" tab in the Sinus pattern dialogue box. Click in the two coloured swatches to set the desired colours. Ideally, you want to choose two shades of the same colour, a lighter and a darker one. The colour choice is up to you.
Choose the "Blend" tab in the sinus pattern dialogue box. Click in the circle next to "Sinusoidal" and type "-0.91" in the number field next to the "Exponent" slider (or you can drag the slider until the number is correct, but it's usually easier to type it.
Choose the "Settings" tab in the Sinus pattern dialogue box. You can play around with the settings, but it is best to start with these suggested settings or you might get frustrated: "11.3925" for "X scale;" "20.2532" for "Y scale;" "5.41" for "Complexity;" and "1586156458" for "Random Seed." Make sure there is a check mark in the box next to "Force tiling?" and a black dot in the circle next to "Distorted." There should be no check mark in the box next to "Randomize" and no black dot next to "Ideal." Of the numerical settings, the "Random seed" number is the most crucial; a variation of just a little will produce a profounding different pattern due to the randomisation. You have more leeway with the first three numbers, so feel free to experiment and watch the "preview" box to see the effect. Click on the "OK" button when you are satisfied. This will fill the image with the pattern.
Save the file as a JPG or PNG image file using the "Save" option in the "File" menu.