okie doke, I've got a similar effect, I will explain the process of adding the color and darkening the edges, the painterly style on either end looks similar to an effect used with the liquify tool, just play around with it, it's fun to get used to anyway.
okay to start, let's get preparation going first
start with a blank canvas with the measurements of 70 pixels wide, and 200 pixels high.
get your bucket fill tool (it's automatically set to gradient fill if you haven't changed it. so it's button will look like the ones shown here, right click the button to get the option to change what the tool its set to.
after that, set your foreground colour, (in the image above, it's the white square) to grey, by clicking it once, a box will come up with loads of colours, try and set it to a mid grey, not too dark or light.
Fill the canvas with the fill tool.
go to edit> define brush preset. feel free to give your brush a name.
Okay, this is where it gets complicated pay attention, feel free to ask questions at this point.
start another new canvas, 1920x1080
go to layer(at the top) > new layer, press enter when a little window comes up.
select the paintbrush tool (it looks like a paintbrush) then look at the top area of the Photoshop interface, to the left, you should see a little circle with a number under it, to the right of it, there's a little arrow. click that.
scroll all the way down to the bottom of the little menu it brings up, select the grey box looking one at the very end with "200" under it.
Go to window> click once on "brush"
click on the box next to "shape dynamics"
click once on the actual text that says 'scattering'
okay input these settings to the right of the little window that you're looking at.
Tick 'both axes'
Scatter : 429%
Count: 1
Count Jitter: 98%
next click the text on "colour dynamics"
all you have to change here is the hue jitter which is this
Hue Jitter: 59%
set the foreground color to red like you did changing it to grey before.
okay, you're done setting up the brush.
now, on your new layer that you made, set the brush size to 90 ( pressing the [ and ] buttons on your keyboard adjusts the size)
towards the bottom of the image, click and drag your mouse as swiftly as you can across the page. you should have a bunch of different coloured rectangles across the bottom of the image like so
(yours will be smaller and the colour will vary, don't worry you're not doing it wrong)
okay it might look pretty, but that's not the effect we're looking for, so let's give it a little more of a blur.
go to filter>blur. Motion blur. set it up as follows:
Angle: 90
Radius: 1031
press okay.
it should now look similar to this:
okay, now we're getting somewhere, but it's not on the image yet.
press the little eye next to the layer that says background.
they won't look as vivid, so right click on the text where it says "layer 1"
click duplicate layer
keep this back for later.
open your image up in photoshop.
For ease of use, I've compiled these colors together for you, it saves messing about.
grab these, paste them into your image onto a new layer, (it should do it automatically)
colors:
name this "blurry colours" (so you know what the hell I'm on about)
go ahead and set its blend mode to overlay
blend modes are found here:
(click it and select overlay)
go to filter> blur> Gaussian blur
Settings are as follows:
Radius 120.5 pixels
press okay.
alright, now the transitions look less solid.
go back and select the blurry lines you did earlier (i'm presuming you know where the rectangle select tool is)
go to edit>copy merged
paste it into your main image. call the layer "blurry lines"
Press command+Shift+U
the lines should turn grey.
set its blend mode to colour dodge.
it'll disappear, don't worry it's there
now go to Image> adjustments>brightness and contrast.
set it up like this
Brightness: +120
Contrast: 0
you should see the lines reappear.
again for ease of use, I'm giving you this, because it's a nut to get right.
paste it in to the main image
set blend mode to multiply
okay now it looks a little dark, lets sort that.
duplicate your blurry colours layer
drag the layer (click the text and drag it) above the black/white gradient layer you just pasted
press command+shift+U
turn its brightness up to 74
set blend mode to colour dodge
okay nearly done!
this is optional:
go to layer> New adjustment layer> hue and saturation
adjust to this:
Hue: 0
Saturation: -41
Lightness: 0
done!
should look similar to this:
any questions, just holler, and I'll elaborate.