How to Create an Interplay of Abstract Light Streaks
This tutorial is inspired by the work of the Lichfaktor collective. You should really take a look at their pictures, which are pure urban poetry. I basically wanted a simple way to create similar light effects without freezing my bones outside at night.
To achieve this we'll use both Illustrator to design the basic shapes and Photoshop to create the lighting effects. Since everything is going to be done with smart objects and layer styles, the final image will be scalable at any size.
Final Image Preview
Before we get started, let's take a look at the image we'll be creating.



Step 1
First, let's create a new document in Photoshop. Set the size to 1000px wide by 1000px height in RGB color mode with a transparent background. To create the background fill, click the black & white circle (Create A New Fill Or Adjustment Layer) at the bottom of the Layers palette and select Gradient from the list. Take a look at the screen capture below to make the adjustements and delete the layer mask by right-clicking on it and selecting Delete The Fusion Mask.



Step 2
Now create a new document in Illustrator. The size and color mode should be the same as the Photoshop document. Draw a wavy shape as shown in the example below and scale it to approximatively 300px wide. Duplicate it below, scale it and rotate it a little. Then go to Window > Brush Libraries > Artistic > Artistic_ScrollPen and apply the second brush (Scroll Pen 10) of the list to both shapes. Delete their fill and set the stroke weight to 0,25pt. Everything is now ready to create the blend.



Step 3
Select the Blend Tool (W) and click where shown below to initiate the blending. It's important to click on those points in this ordrer as the appearance of the object depends on where and when you initiate it. Refine the effect by double-clicking on the same tool in the Toolbox. A dialog box opens up where you have to select Specified Steps in the menu and enter 60 as the value. We now have a beautiful wave facing us.
Just one more thing: don't forget to turn the stroke color of the blend to white. Now you can copy and paste your shape into Photoshop as a Smart Object. Name this new layer "Shape 1."



Step 4
Transform the shape you just pasted (Command + T) to flip it horizontally and scale it. Turn the blending mode of the layer to Hard Light and apply an Outer Glow by clicking on the FX button down below the Layers palette. Starting from the default settings, modify those marked in red in the image below. Then select the Gradient in the first section of the window and click on the spectrum to edit it.
A new dialog box opens in which you must select Noise in the Gradient Type menu. This very simple operation creates multiple strokes of color around the shape. Click several times on the Randomize button in the bottom-right of the window until you get something like in the example, also activate the option Add Transparency.



Step 5
Let's now apply another layer style to give color to the shape, use Color Overlay with the following settings: Color Burn, #0024ff, 100%. You should get something like this:



Step 6
Notice the main area of the shape is totally solid and therefore, quite pointless for this composition. Click on the Add Layer Mask button down below the Layers palette and with a big black soft round brush, paint that area. Accuracy isn't required, just take care keeping the left part of the shape visible.
One little tip that will improve your painting efficiency: you can adjust the opacity of the current tool just by typing the desired percentage on the numeric keypad on the right side of your keyboard. For example, typing 2 with the Brush Tool (B) selected makes your brush opaque at 20%. The first shape is now finished.



Step 7
To create another shape without starting the drawing process from the beginning, double-click on the thumbnail of the first shape layer to open it in Illustrator. Select the blend and set its stroke color to black. Go to Window > Brush Libraries > Artistic > Artistic_Ink and apply the 10th biggest brush titled "Marker." Double-click on the Blend Tool (W) icon from the Toolbox and set 20 as the value for the Specified Steps option.
Now in the Brushes palette, double-click on the selected brush (the one you just applied) and in the dialog box enter 30% for the size and activate the Proportional checkbox. After clicking the OK button, a dialog box asks you whether you want to apply those new settings to the brush itself or not, choose Apply To Strokes. Turn the stroke color of the blend to white, then copy and paste the new blend into Photoshop as a Smart Object. Name it "Shape 2" and close the document in Illustrator without saving the changes (unless you want to apply those last changes to the first shape you drew and adjusted in Photoshop).



Step 8
Transform the shape (Command + T) and scale it proportionnally at 190%. Duplicate the layer styles of the "Shape 1" layer using this little shortcut: drag the FX icon of this layer holding down the Alt key of your keyboard onto the "Shape 2" layer, and you're done! Just set the blending mode to Linear Light. Using the same technique as in Step 6, hide the top-left part of the shape.



Step 9
To create the next shape, open the second one in Illustrator. Next, turn the stroke color to black and in the Brushes palette delete the one which is selected. A dialog box pops up, select Remove Strokes. Using the Direct Selection Tool (A), select the uppermost path and check the box Dashed Line in the Stroke palette. Enter 1pt in the first one of the boxes below it and leave the other ones blank. Select the other path (still with the Direct Selection Tool), set the weight to 1pt, and dash it with 9pt in the first box. Also, activate the Round Cap option for both paths in the same palette.
Don't forget to set the stroke color to white before pasting it into Photoshop. Scale it at the same size (190%) and in the same place as the second shape, nudge it a few pixels above and on the right to avoid hiding the first shape. Next, it's the same drill again: name the layer, copy the prior layer styles ,then modify them, and mask the object.
Here are the settings for this third shape: Normal as the blending mode for the layer, a reddish spectrum for the Gradient used in the Outer Glow (use the sliders in the Gradient Editor to restrain the colors as shown below), #ff0000 as Color Overlay and Linear Light as the blending mode for this last layer style.



Step 10
The design is beginning to look good but lacks some volume. We will achieve that by creating a colored surface on the frontmost swirl. Duplicate the third shape by Alt-dragging it between the two first Vector Smart Objects, then name it "Shape 4." Nudge it approximatively 100px upwards and 10px to the left (press Shift while hitting the keyboard arrows to make 10px increments). Shift-click on the mask to temporarily deactivate it and double-click on the FX icon of the layer to modify the Outer Glow (see the image below for the settings).
Don't forget to move the sliders at each extremity to use the whole spectrum while modifying the Gradient in the Outer Glow, nor unchecking the Color Overlay layer style. Now go to Filters > Blur > Gaussian Blur and apply it with a 50px Radius. Notice a new section appeared below the thumbnail of the layer, and a new icon too. You may delete the mask of the Smart Filter by right-clicking on it and selecting Delete Filter Mask. Set the blending mode of the layer to Screen with 10% Opacity.
Now click on the layer mask to reactivate it, press D on your keyboard to reset the foreground/background colors and press Alt + Backspace to fill the mask with white. Now hide the right side of the object.



Step 11
Let's add some more volume to our composition. Duplicate the third shape by Alt-dragging it above itself, name it "Shape 5," and nudge it 20px to the right. Shift-click on the layer mask thumbnail to temporarily deactivate it and double-click on the FX icon of the layer to modify the Outer Glow (see the image below for the settings). Use Color Overlay with the following settings: Multiply, #fee581, and 70%.
Now click on the layer mask to reactivate it, fill it with white, and hide the right side of the object.



Step 12
Let's explore a little more with the strokes applied to blends in Illustrator: double-click on the thumbnail of the first shape layer to open it in Illustrator. Select the blend and set its stroke color to black. Go to Window > Brush Libraries > Artistic > Artistic_Ink and apply the 8th biggest brush called "Galaxy."
Double-click on the Blend Tool (W) icon from the Toolbox and set 10 as the value for the Specified Steps option. Use 10pt for the stroke weight of the upmost path, 1pt for the other one, and 10% for the size of the brush. Turn the stroke color of the blend to white, then copy and paste the object into Photoshop at 190% size and above all the other layers. Nudge it, and give it the same layer styles and blending mode as the first shape, then mask it.



Step 13
Re-open the very first vector smart object from its thumbnail in the layers palette and turn it black. Next, release the blend using the shortcut Command + Alt + Shift + B, double-click on the brush thumbnail in the Brushes palette and activate the Flip Along checkbox in the Flip section of the Art Brush Options box. Turn the stroke color of the blend to white, then copy and paste the object into Photoshop at 190% size and above all the other layers. Nudge it, give it the same layer styles as shown below with Screen as the blending mode for the layer. Use Color Overlay with the following settings: Overlay, #fff600, and 100%. Finally, mask it.



Step 14
We are not completely done with the vector shapes but let's take a pause to look at what we've done and add some contrast to our light streaks by creating an Adjustement Layer. Click on the black & white circle at the bottom of the Layers palette and select Curves from the list. Take a look at the images below to make the adjustements and delete the layer mask.



Step 15
Let's jump back to Illustrator and create a new document in which we draw an Ellipse (L), measuring approximately 440px width and 480px height. Next, apply the first brush from the ScrollPen library (Scroll Pen 1) to it and reduce the size of the brush, still by double-clicking its thumbnail in the Brushes palette. In the example below, I used a size of 40% and Flipped it Along. Delete the fill of the object, turn its stroke color to white, then copy and paste it into Photoshop.



Step 16
Apply the layer styles of the first shape to it and modify them a little according to the image below. Scale, rotate, nudge and duplicate the object twice to give more strength to the swashes. Select those last 3 objects in the Layers palette and hit Command + G to gather them in a group, name it "Swashes." Add a layer mask and use it so that only the right side remains.



Step 17
Last but not least, let's take care of those big red trails in the background. In Illustrator, create a new document and draw a wave. Next, duplicate it, scale it down a little, nudge some anchor points, and create the blend with 10 steps. Select the whole blend and Dash it with 11pt and 23pt in the first two boxes, leaving the other ones blank. Also, activate the Round Cap option in the same palette. Use 3pt for the stroke weight of the upmost path, and 1pt for the other one. Turn the stroke color of the blend to white, then copy and paste the object into Photoshop just above the "background" layer.



Step 18
Scale it at 210% and duplicate the layer styles of the "Shape 3" layer. Now modify them according to the image below. Duplicate it, nudge it a few pixels leftwards and enter 50% as Opacity for this last layer. Gather those last two shapes in a group (Command + G) and name it "Red trails." Let's now fade those out, not using a layer mask on the group itself, but individually for each trail. In fact, the uppermost one is only used to emphasise some areas of the other one.



Step 19
Here we are, the final step. We are going to slightly sharpen some areas of the composition: hit Command + Alt + Shift + E on your keyboard to merge all visible layers into a new one. Now name it "Sharpening."
Go to Layer > Smart Objects > Convert To Smart Object. Next go to Filter > Other > High Pass and enter a 2px value. Change the blending mode of the layer to Vivid Light and add a layer mask to it. As we mainly want to sharpen the red trails, Command + Shift-click the thumbnail of those two smart objects and — with the "Sharpening" layer still selected — click the Add Layer Mask button we already used before. Now the sharpening appears only on the area of the red trails. Paint a little more in the mask to enhance some other areas like the edges of the big green and yellow swashes.
One last tip before leaving: the whole image is scalable at any size without any loss of quality (assuming your computer can handle it) simply by activating the Scale Styles option in the Image Size dialog box (Command + Alt + I.) Enjoy!



Final Image
You can view the final image below.



