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dmorigin

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About dmorigin

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  1. It works until you export it as a file (e.g. Tiff). Then everything is the same again. alpha_channel_test.afphoto
  2. Two different examples. The first one containes a normal map and a displacement map. The displacement map is stored in the alpha channel. At this one it seams to work. The other examples is a hand painted example. I don't know how I can paint in the alpha channel directly. So, I have generate a mask layer from the alpha channel. At this example, there is data in the alpha channel, but it is not exported. combined_masks.afphoto hand_painted.afphoto
  3. It seems I misunderstood "Selection" at this point. But how to export with Alpha Channel? There are additional settings. One of them specifies the background color. In the color selection there is a circle with a red line. Is this "transparent"? If so, it doesn't work. Because in the exported image the alpha channel is always completely filled.
  4. I have a problem packing maps in the four channels. I know the tutorial video for Channel Packing. However, the alpha channel is not used in this tutorial. But I use exactly the technique shown there. As soon as you use the alpha channel, the RGB channels are modified according to the information in the alpha channel. This is probably due to how Affinity Photo uses the alpha channel. This is not only used to give the transparency, but also to create a gradient. I have added 3 images to show this better. The image "all_channels.jpg" shows the resulting image as you would normally save it as png or jpg. The image "only_alpha_channel.jpg" shows how Affinity Photo created the alpha channel. You can see the soft edges. The image "only_red_channel.jpg" shows the content of the red channel. Some edges are soft others are not. Where the colors red and green overlap a gradient is created from 1 to 0 (or 255 - 0 in 8Bit). However, where no color is adjacent, this gradient is created by the alpha channel and the color value remains at 1 (255 in 8Bit). The problem now is that as soon as you put data into the alpha channel the RGB channels will be recalculated. This happens if you first fill the alpha channel and then the RGB channels or first the RGB channels and then the alpha channel. If you now have a normal map and want to place the displacement map in the alpha channel, the normal map will be destroyed by the recalculation of the RGB channels based on the information in the alpha channel. Is there a way to prevent this recalculation?
  5. The export function of Affinity Photo reduces the size of the image when exporting as TIFF if there is no color information at the border and you export without background. As long as you save your document with background, the image keeps its size during the export. It is indeed possible to manually reset the size to the correct size, but then the reduced size will be stretched to the set size. This behavior can be reproduced quickly. Create a transparent layer, paint a black dot in the middle and export. I did this and attached it to the post. This behavior destroys the image data when the document has certain specific size requirements. For example, textures that must have a size in the power of two. tiff_without_bg.tiff tiff_with_bg.tiff
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