How to create a seamless repeat pattern in Photoshop
Hand draw an image with an irregular shape. Do not touch the edges of the piece of paper. Scan your image via Photoshop. Go to file/import/ WIA Support Save as PSD file
Create a new page in Photoshop (file/new) and input the settings shown. Give your page a title and save as a PSD file.
Copy and paste the image you have scanned in onto the 5x5cm page. Select the area using the rectangular marque tool. Then select edit/copy Paste the image onto the 5x5cm page by selecting edit/paste
If the pasted image is too big or small. Edit the size by selecting edit/transform/scale *when altering the scale press and hold the shift key to keep the proportions exact Alter the scale of the image so it fits on the page. Do not let the image touch the edges.
Click on the background layer
Change the colour to something that stands out. To select a colour double click on the swatch and select a colour The select the fill bucket and click on the page
Remove the area around the image. To do this select the layer with the image on, select the magic wand, click on the area to be removed and press delete. To remove the marching ants press select/deselect (or Ctrl &D) *the magic wand will highlight areas of a similar colour, you can alter the tolerance up or down to alter how close the colour match is
Change the background back to white. By selecting the colour white by clicking on the swatch Remember to select the background layer
Duplicate the layer by right clicking on the layer 1 and selecting duplicate layer
Whilst on layer 1 copy select filter/other/offset
You need to add measurements based on how many pixels the image is made up from. This particular size image is made up of 1500 pixels. To check this go to image/size
Half the pixels and enter the value 750 in the horizontal and vertical boxes. Ensure wrap around is highlighted. Notice the image is quartered. You have now created a repeat swatch. Save this image as a PSD file.
Now you have create your pattern swatch you need to do something which is called define pattern. To do this select the area with the rectangular marque tool, go to edit/define pattern and press OK
Create a new A4 page by selecting file/new. The measurements will populate automatically. Make sure the colour mode is RGB colour
Select the paint bucket tool and go to the top right hand corner and select pattern on the drop down. Then select your pattern in the drop down box next to it.
Now you have selected the pattern you have created, click on the new A4 page using the tabs on the top. Your pattern will seamlessly be repeated on the page. .
If the repeated pattern is too big or small you can alter the size. You would have to go to the original swatch and alter the size by selecting image/image size and put in the new measurements. Ensure the proportions are constrained. Then complete the processing of define pattern again to create a new one.
Now you know how to create a repeat pattern. Experiment with different images and try adding colour. To add colour you would need to do this to the original image once it is scanned in and you have removed the outer white space using the magic wand. Add colour before the image is duplicated and quartered.
You can add colour using the paint bucket tool to fill sections in. This will only work if there are no gaps in the section, otherwise the colour will leak out. You need to change the fill bucket from background to foreground. Select a colour and fill sections in by clicking on the area.
Once you are happy with the added colours, you can then duplicate the layer and quarter the image. If you do not want a white back ground you can change the background by using the fill bucket tool.
If you want to fill the space with more pattern you can do, provided you do not touch the edges.