Perlin Noise

[John Rostron]

I was trying to follow a Photoshop tutorial on creating clouds and found that, in Affinity, Perlin Noise should do this for me. I created an empty file 800 by 800 px, RGB/8bit and set the foreground/background to black/white.  I then duplicated it to create an editable layer. I then selected Filter>Noise>Perlin noise. No matter what I did to the parameters there was no effect on my image. It remained white. I did click on Apply!

 

I have also tried to do the same with a 50% grey image, to no avail.

 

What should I be doing?

[R C-R]

When you first create a new AP document, there are no layers, so you really are not "duplicating" anything when you add a pixel layer to it. But as long as you have a pixel layer selected in the Layers panel, Filter>Noise>Perlin Noise should have a visible effect on that layer, using the current foreground/background colors.

[uncle808us]

Cool Easy clouds!

 

[John Rostron]

55 minutes ago, R C-R said:

When you first create a new AP document, there are no layers, so you really are not "duplicating" anything when you add a pixel layer to it. But as long as you have a pixel layer selected in the Layers panel, Filter>Noise>Perlin Noise should have a visible effect on that layer, using the current foreground/background colors.

Yes, it should; but it doesn't. I did have two (blank) layers visible, with the top one selected.

 

I will try and generate a screenshot.

[toltec]

6 minutes ago, John Rostron said:

Yes, it should; but it doesn't. I did have two (blank) layers visible, with the top one selected.

 

I will try and generate a screenshot.

This is all you should need

To get this

[John Rostron]

Thanks @Toltec.  I did get the Colours panel something like yours. As you can see from the screenshot, there is no layer identified, and it did not allow me to duplicate it (grey in the Layers panel) and the lock symbol was on. When I clicked on Filters>Noise, Perlin Noise was also greyed out.

 

I had previously tried with a fill layer of 50% grey. This allowed me to duplicate it, and brought up the Filters>Noise>Perlin Noise panel, but it had no effect.

[John Rostron]

Quote

 

I have got it to work, by what can only be described as a circuitous route. From my blank layer, I created an empty Levels Adjustment layer, then Merged visible. This created a pixel layer which responded to the Perlin Noise filter as expected. 

 

I realize that the Fill layer was not appropriate at all.

[R C-R]

1 hour ago, John Rostron said:

As you can see from the screenshot, there is no layer identified, and it did not allow me to duplicate it (grey in the Layers panel) and the lock symbol was on. When I clicked on Filters>Noise, Perlin Noise was also greyed out.

That is because there is no layer, no "it" to duplicate, no 'blank' layer, no layer at all. The lock symbol in your screenshot does not belong to any layer. Like the gear symbol next to it it is part of the Layers Panel. It is used to lock a selected layer.

 

As has been mentioned, the Perlin Noise filter replaces the content of a pixel layer using the current foreground & background colors. Thus, it does not matter if the layer was previously filled with grays or black or white, but the layer must exist, it must be selected, and it must be a pixel (raster) layer -- if it is not the Assistant by default will rasterize image or vector (but not fill) layers & apply the Perlin Noise filter to that.

[John Rostron]

Thanks @R C-R for your explanation. It does beg the question, if I want to start off with a new image and generate a Perlin Noise effect, what is the most effective way to generate a new pixel layer for it to work on? Would Rasterise the new non-layer work? (I am away from my desktop at present.)

[toltec]

In the example I posted, I just clicked on this

 

or you could just go Layer > New Layer or press Ctrl + Shift + N. 

 

Either option will produce a blank, Perlin Noise ready, pixel layer. 

 

If you then just go Filter > Noise > Perlin Noise it will use whatever two colours you have selected in the colours panel. You can change the colours and the "noise" will update to reflect this. Once you press "Apply" it is set in pixels and can't be changed.

[R C-R]

43 minutes ago, John Rostron said:

Would Rasterise the new non-layer work?

Again, there is no "non-layer" to rasterize. You must create a layer & select it for there to be a layer for the  Perlin Noise filter to affect.

[John Rostron]

Thanks Toltec and R C-R. That gives me a way forward and makes some lind of sense even if it is not intuitive. 

[A_B_C]

Think of a document without any layers as an empty container, an empty filing tray, if you want. Now, a filter will never apply to this container, but only to contents you put into. You wouldn’t, for instance, take a pencil and draw on the filing tray that sits on your desktop, but you would draw on a piece of paper and store your drawing there. In much the same way, the filter will not affect your document as such, but only the contents, that is, the pixel layers, stored within that container. Take it with a grain of salt, but I hope this simile is useful … 

[R C-R]

It also might be a bit less unintuitive if you consider why Affinity does not automatically create a new layer when you create a new document like many other apps do.

 

One of the possible reasons for creating a new AP document is to place one or more image layers in it, using the File > Place menu item. These image layers (those identified by an "(Image)" suffix in the Layers panel) retain their pixel resolutions regardless of how they are resized on the canvas, which means you can resize, move, rotate, or even skew them non-destructively. This is because they are not resampled to the document's resolution (as determined by the document's DPI setting) unless/until you print or export the document to something other than the native Affinity filetype.

 

This is perfect for laying out one page montages of photos, creating simple flyers with a few photos or illustrations, & similar uses. (I have created "lost dog" & "found dog" fliers for friends this way, combining one or two placed photos & a few text objects with relevant contact & descriptive info.) Automatically creating an empty pixel (or whatever) layer for this use case would be superfluous & perhaps annoying. To me it certainly would be -- I hate it when apps are programmed to assume something about my intent.