[Affinity Photo gradient map with a transparent background?]

Wow guys thank you so much... I did not exspect to get an answer the same day, but that really speaks for the forum.

Using a blackscaled copy of the flames perfectly worked out for me here! I have been working with Photoshop for years and recently switched to Affinity, but I never counquered a situation like this.

So both of you, thank you for your time and efforts and have a nice day

[Affinity Photo gradient map with a transparent background?]

I have a project in Affinity Photo where an electric guitar is on fire. I first created the flames in white with a special brush and then colored them with a gradient map.

Since this is a t-shirt design, the print shop logically needs it without a black background. However, if I remove this, the gradient map does not produce the black-red-yellow-white gradient that I would like for the flames, but a continuous, disgusting and bright yellow.

I conclude that the black background plays a role in the creation of the flames and I would like to know if you can think of any method or way of exporting the image as described.

I uploaded the project file and an image of the disgusting yellow flame I want to prevent.

Thanks in advance to all respondents :)

Mazze_Shirt.afphoto