One of the easiest ways to create an image for screen printing is by using photoshop. One is the first principles is to use a high definition photograph nothing less than 4 mega pixels. If the photo is colour you will need to change the image to greyscale, you can do this by going to image / mode / and then changing it to greyscale. From this you can basically do a number of different things to change the image, depending on what your desired outcome is. A effective way to give your image an more dynamic look is to adjust the tonal range. This can be done again by going to image and selecting brightness and contrast, you’ll then be able to control the settings by moving the bars across.
The images above show the original image that I used and the digitally adjusted. I put the contrast quite high as to show more white in the overall look. Below are two images that I have used filters to create different effects.
I had a lot of fun playing with the different filters on photoshop. However alot of them were not suitable for screen printing. However it was helpful for future projects.