Friday, February 02, 2007

Transparent Images - Clean Edges

Shelley asked if I had any tips about getting clean edges on transparent images.

There are a few things that I know of and that can help.

First of all, if you are creating the design on the computer using a graphics program than make sure to turn off the anti-aliasing. That will make the edges crisp and won't create the white pixels around the edges. Starting with a dark background (instead of the usual white) even with the anti-aliasing on will make the edges look more natural on dark apparel.

If you are hand drawing or painting the design and than scanning it it will be a bit harder (but not impossible) to cut off the white pixels. What you can do is zoom the image so you can see the pixels well and than use the select tool experimenting with the threshold until you get a selection line nicely separating the too light pixels from those that are dark enough to keep. Once you have separated what you want to keep it's easy to make the rest of the picture transparent (see the internal links in the sidebar to find the link to the transparency tutorial).

Finally, if the white pixels are equally spread around the edges of the design you can select the area you want to keep and use Select/Shrink feature to lose the white pixels. Depending on the image size and the size of the anti-aliased area you will have to shrink the selection by more or less pixels.

Hope that helped a bit.