Noise at begin and end of gradients

[vital_net]

Hello,
 

• I'm on Windows 10, Affinity Designer 1.8.3.641, but exactly same issue on Affinity Photo 1.7.3.481
• When making a gradient from transparent white to a solid black over a blank transparent document, there is some black pixels noise. This only happen with transparent document. Same issue in Affinity Photo. Same issue with older versions.
• Why an issue ? : This is a big one because I craft textures for video games, especially for shaders and I need perfect continuity, and precise values. The noise is made of pure black and white (opposite) in this case. I also need textures to be perfectly tillable so noise is an issue.
  I need the gradient tool to be reliable.

 

1. Open Affinity Designer 
2. Create a new document
3. Document Setup>check transparent background
4. create a transparent rectangle to fill the image.
5. trace a gradient with the fill tool in the middle of the screen. From Transprent White to solid Black.
6. export to PNG or TGA
7. If you open the image, the RGB channels have black noise at the begin of the transprent gradient. 

I tried with other software, and they export a clean output. Also not format depend.

Thank you

NoiseGradientIssue.tga GradientIssue.afdesign

[Sean P]

Hi vital_net,

This isn't a bug - the exporter actually dithers gradients on export to make the gradient look better and avoids any banding that occurs. There is an improvement logged with development to disable this dithering which would give users the best of both worlds! I will pass your comments on.

[vital_net]

Using a fx color overlay with 0% did the trick, but only works with Affinity Designer, not Affinity Photo.

I'd like to be notified when this option will be available.

Thank you for the answer.

[lepr]

On 5/6/2020 at 4:42 PM, vital_net said:

Using a fx color overlay with 0% did the trick, but only works with Affinity Designer, not Affinity Photo.

 

The trick works exactly the same in Photo and Designer.

There was a difference in the type of object that you filled in each app: a raster object in Photo versus a vector object in Designer. All Affinity apps support both types, but the different types get filled differently by the Gradient/Fill Tool.

In both apps, a gradient applied with the Gradient/Fill Tool is immediately rasterised with dither and baked into the object if the object's type is Pixel (that's a raster object), and so the fx trick cannot help prevent dither there.

In both apps, a gradient applied with the Gradient/Fill Tool remains vector if the object's type is vector (such as a Rectangle), and so the fx trick can prevent dithering when that vector object is subsequently rasterised.