How do I erase everything that is black in an image?

[Norway4T]

I have a collection of fractal images that I've made that look like flowers. The fractals consists of the multicolored fractal "flowers" on a black background.

I import the fractal images into Affinity Designer (I eventually want to make vector brushes from various arrangements of these fractals) and arrange them, slightly overlapping each other. Now the black backgrounds on each image obscure the image on the layer underneath.

So, I select all the images and change the blend mode to screen. Now I can see each flower through the layers of images, and so far so good.

Now I want to remove everything in the images that is black, so only the color of the flowers are visible and export that in a .png with transparent background. I have tried absolutely every and all combinations that may remove the black frames when I export. I opened the Affinity Designer document in Affinity Photo to see if there was some way tweaking the alpha channel to remove the black. No luck.

I am fresh out of ideas after plodding around in this for two days.

A fix to this problem would be most welcome!

[firstdefence]

Do you have an example fractal, so we can see what you are using?

Which fractal app are you using to generate these fractal flowers, Jwildfire, chaoscope, mandelbulber etc?

 

 

[Norway4T]

Sure firstdefence, but I'm not sure how that's going to help. The resulting fractals are merely jpegs and tiffs with a black background, just like any other picture with a black background. I have used Fractal Architect 5 to create these. The problem described above is in order of the last picture to the first. All I need to know is to remove everything that is black in the picture below.

 

[firstdefence]

The reason I asked about the software was how the export works and whether it would be easier in the future to learn how to export with without a background (transparency).

Fractals on a black background look very different to fractals with transparency. By removing the black "post fractal render" some of the fractals detail will be lost, as opposed to rendering from the fractal software without a background.

But if you want to do it by removing the black, invert the layer/s and use Filters > Colour > Erase White Paper.

[wonderings]

Not sure there is an easy way to just remove black and make the background transparent, someone else can probably confirm or give a solution. 

Are you not able to create these with a transparent back to begin with rather then try and fix up after?

[firstdefence]

This is using the erase white paper filter

 

[lepr]

Using the Black and Alpha output of a Channel Mixer Adjustment

remove black background.afphoto

[Norway4T]

Thanks anon2, I will try that macro out.

[Norway4T]

Firstdefence & wonderings,

THANK YOU for all the kind help you have provided. Yes, I realize in the future, it will probably be easier and yield a better quality to export them on a transparent background. These were just some old, high res renderings I had laying around, and I wondered if I maybe could use them for some illustrations to a children's book I'm writing.

Thanks a lot to all of you, Firstdefence, wonderings and anon2! MUCH appreciated! ⭐️⭐️⭐️⭐️⭐️ 👍

[lepr]

17 minutes ago, Norway4T said:

Thanks anon2, I will try that macro out.

No macro. The document contains a Channel Mixer adjustment layer.

[Norway4T]

I see. Thanks, anon2! Haven't had the time to check it out yet, but I will! Much appreciated! 👍