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dmorigin

[By Design] Tiff Export changes document size

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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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Hi @dmorigin,

Welcome to the forums. 

This is not a bug, but how the export works. 

When you Export "Selection without background", you're exporting the selection, at the selection's clip boundaries, and not at the document size. Basically, it's the same as doing Document > Clip canvas. This way, any "transparent" information will be clipped during the export. 

If you want to export it with the document size, you would have to either use a slice on that layer and resize it to fit the canvas, or, enable transparent background and export the whole document. 

Thanks,

Gabe. 

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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.

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The alpha channel is automatically exported. Not really sure I understand. The alpha channel is automatically exported, based on the contents of your slices. If you give us an example, we can help you out. 

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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

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4 hours ago, dmorigin said:

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

When the document does not have Transparent Background enabled, you will not get an alpha channel in the TIFF or PNG export, which is the case with your "hand_painted.afphoto".

Your "combined_masks.afphoto" does have Transparent Background enabled and an exported TIFF or PNG will have an alpha channel unless every pixel of the export is fully opaque.

 

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