Hi, before we start off, the first thing you will need to have is grunge brushes, just search for them on google if you don't have them, we are going to create a fire image very similar to this:


First off, start with a new image 500x500 with a transparent background, now select the gradient tool and use these settings:


and create a gradient that looks like this:


Now create a new layer and select filter>render>clouds, now set the blending mode to Darken, you should now see something like this:

Now go to filter>distort>twirl and select -75 or +75.

Afterwards duplicate your clouds layer and set it's blending mode to Linear Light. Finally press ctrl+u and change the colors on both layers to these settings:


You can be very flexible but the idea I was looking for was incredibly vibrant colours as this is a result you should have:


Now you can leave it like this if you want or you can create an even better looking result, Go to file>new and make another 500x500 document with a white background. Now create a new layer and select the gradient tool, use these settings:


Now start doing an assortment of random gradients all over the screen but try not to make them to thick. After that you should have an image that looks like this:


Now do filter>stylize>find edges then filter>artistic>plastic wrap with settings of strength 10, detail 10, smoothness 10. Now you should have something that looks like this:


Now we should colour this, create a new layer and fill it with whatever colour you want, since we are wanting a blaze look fill the layer with anything from red to orange, now set the layers blending mode to color. You should now have this:


We are almost there, now select the rectangular marquee tool and set it's mode to fixed size and have your average sig size there. Now select part of the image that has the least amount of dark lines in it but include some. Now select edit>copy merged then select File>new and create a new image with a transparent background, the size should be your sig size. Now paste it on a new layer. Now go back to our cloud fire and copy the sig size from that, then paste it on the first layer of your sig image. You should now have this if you followed it:


(the clouds are behind this layer)
Now go onto your webbed layer and set it's blending mode to whatever you want, Darken, soft light and overlay are good choices.
Now that we have created our background for our sig, select the first layer (clouds) and equip yourself with your grunge brushes, press D before doing anything and then go at the image with your brushes, vary them and you will end up with something like this:
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This method is very modifiable and can open up a whole new way of creating images due to it's flexibility, if you want a very dank look, all you need to do is make the colours pale or if you want a very blazey look then you will need to make the colours very vibrant
Here is a fairly nice blaze effect that has a sort of burnt house look to it, after you have done this you can create some very nice effects like this:


This pic was done in the same way only the colours used were less vibrant