1. Create a new image, 600x180 and make the Contents Transparent. I chose this because we'll be making a 15x15 pattern to paste and 180 is divisible by 15 (maths nerd!). This will be our main image.

---

2. Create another new image, 15x15 and make the Contents Transparent.

---

3. On the 15x15 image, press CTRL + A to select all and go to Edit > Stroke... choose 1px in black and change the location to Inside. Click OK.

---

4. Now leave your selection active, if its not, press CTRL + A again. Click the Marquee tool  and press the down arrow and right arrow once each to move the marquee selection. Press Delete and CTRL + D to Deselect.

---

5. Now go to Edit > Define Pattern, name the pattern and click OK.

---

6. Switch back to the other 600x180 pic so we can start making this effect. Click on the paint bucket tool, if you can't see it then click + hold the Gradient button and it will show up. Once you have done that, on the top taskbar, in the Fill drop-down menu, select Pattern and choose the pattern you just defined.

---

7. Create a new Layer and fill this new layer by clicking on the image with the Fill tool selected.

8. Grab the Wand tool now  and make sure the Tolerance = 0. This is the artistic part now, here, you choose a strong colour and click in the squares one by one, pressing ALT + Backspace to Fill Foreground Colour. Contunie this randomly around the page like so:

9. Now repeat step 8 but selecting a lighter version of the colour you chose last time.

10. Continue steps 8 + 9 untill you get an effect you like.

11. There are endless possibilities with colour effects for this tutorial and you can put in other effects and backgrounds of your choice to make it look Gnarly!