Updated : 2021
How to create a rectangle themed pattern in Photoshop tutorial using lines and random fill script.
The key thing is to set up a rectangle in the first place. The rectangle shape for the background can be long or thin or wide.
The rectangle line can have any color fill such as gradients or a solid color. It can have effects added to the rectangle line shape by using layer style. Make certain that you choose the 'shape layer' option or if you are using the pixel option, use that on a new layer so you can delete the background.
Delete the background layer via the layers panel. The Photoshop rectangle line is selected by using the rectangular marquee tool. The line design / rectangle design can be as simple as that but you can create far more complex rectangle designs such as parallel lines, lines with different fills, pattern fill lines, dashed lines and many more.
Define the rectangle shape via the edit menu define pattern command.
To create a random filled background using the created line pattern, go to the edit menu and fill and select the pattern option and the rectangle shape and check the script check box.
Go to the next panel in the fill and set the density and color randomness etc. Adjustments can then be used on the rectangle shape filled background such as Photoshop adjustment 'vibrance' etc.
This tutorial shows how to take a humble rectangle shape and create a vast range of different colorful random filled background in Photoshop
All kinds of rectangles can be created using the rectangle tool in Photoshop such as thin ones, squares, wide rectangles and many others.
You can use the rectangle tool (press U on the keyboard) once or multiple times to create all kinds of unique rectangular designs. To use those shapes as a source for a pattern and in particular one for the random fill script, it is best to add the rectangle (rectangles) onto a layer (or layers).
You can use them with a single color or gradient or a pattern as well, along with a stroke.
You can also combine that layer with a layer effect such as a shadow or you can convert it into a smart object and combine with effects such as paint daubs and blurs.
The key thing though for the random fill or pattern scripts in Photoshop is to remove the background so just go to the layer panel and delete the background leaving only the rectangles as this means the random fill will not be filled with a white background (if white).
Select the rectangle tool found in the toolbar
set to shape layer
Create a long vertical rectangle
set color such as to a gradient or solid color
layer menu
layer style
add drop shadow etc
Select the rectangle tool
set the shape option to shape layer
Set the color etc
Add effects such as shadows etc
Go to the layers panel
Delete the background layer by clicking the trash can at the bottom of the layer panel
Edit menu
Define pattern command
flatten document and deselect any selection
Of course, there are many other variations that can be used such as adding different effects or perhaps adding multiple rectangle lines and different colors and different angles and sizes
Go to the edit menu
fill command
select the pattern option
select the script check box
set the drop down to random fill (or any of the others)
select the correct rectangular shape tile
select the random fill option
Click OK.
A dialog will appear allowing you to modify the density as well as scale and rotation and color and brightness etc. Depending on the size of the document / tile, the preview will loosely represent the end result (not really sure if the preview is actually showing a part of the result or it is just occasionally inaccurate).
Anyway, you will see a jumble of lines filling the preview and you can increase or remove lines by changing the density. You can always apply the fill and then add a new layer and then add another random fill to totally fill the image.
You can apply the Photoshop fill multiple times so instead of very low density design, you can have an image totally filled with your rectangle shapes.
You can set the settings in numerous ways such as having randomized color by changing the color and brightness settings and putting them to the max.
You can also have all the lines pointing upwards or their default position, if you want to randomize the rotation click the rotate pattern box.
You can also then use multiple layers and adjustment layers to create a randomly colored jumble of lines. The layers can also have effects added to them so you can have one layer blurred and another as is.
You can also create thin and long lines and then set to no rotation in the panel to create an extreme thin line pattern design.
You do not need to keep the rectangle lines and pattern in the same color and form as before and effects such as blurs as well as adjustments such as black and white adjustment layer can be added to the artwork to create all kinds of wonderful variations of backgrounds from a single rectangle line
Thin line rectangle sources and the rotation has been turned off creates an intense line design
You can now simply add an adjustment layer above to the rectangle shapes design via the layer menu and new adjustment layer such as adding a vibrance or hue and saturation or black and white, multiple adjustment layers can be added to the rectangle line design.
Effects can be added to warp and distort the lines such as filter menu and distort and wave or perhaps use the motion blur and set it to upwards and set the radius to create color streaks from the rectangle shapes pattern design.