DavidJoons Posted March 24, 2021 Share Posted March 24, 2021 This should be so simple, I can't believe I can't do it. I have two images (both exr). One has a transparent background. I just want the one with the transparent background on top so they are (crudely) composited. With the lower image appearing where the transparency is on the upper image. Once I get them into Affinity (Photo or Designer) I can't make it happen. I thought the way to do this was to pop the top image above the other one, change it to Add and that would do it. What happens is the top image is half visible, like a ghost. As if it were partly opaque. But the opacity settings for both the layers are at 100%. This is bread and butter stuff I am sure, but I must be missing something super basic. I could do it in seconds in gimp, well - if they were png I could, but I am lost here for some reason. I don't want to mask anything manually. I'll never get it as accurate as it already is. Any help much appreciated! Quote Link to comment Share on other sites More sharing options...
NotMyFault Posted March 25, 2021 Share Posted March 25, 2021 Hi David, what happens when you just use blend mode normal? It should do the trick. Can you use the info panel and check if the background is really shown as transparent (alpha equal to 0 when cursor is at position of background pixels)? Only the layer with transparent background should be active, all other layers de-active during this check. One assumption is the pixels RGB values may be using pre-multiplied alpha, which needs to be adjusted by a filter. Quote Mac mini M1 A2348 | Windows 10 - AMD Ryzen 9 5900x - 32 GB RAM - Nvidia GTX 1080 LG34WK950U-W, calibrated to DCI-P3 with LG Calibration Studio / Spider 5 iPad Air Gen 5 (2022) A2589 Special interest into procedural texture filter, edit alpha channel, RGB/16 and RGB/32 color formats, stacking, finding root causes for misbehaving files, finding creative solutions for unsolvable tasks, finding bugs in Apps. My posts focus on technical aspects and leave out most of social grease like „maybe“, „in my opinion“, „I might be wrong“ etc. just add copy/paste all these softeners from this signature to make reading more comfortable for you. Otherwise I’m a fine person which respects you and everyone and wants to be respected. Link to comment Share on other sites More sharing options...
DavidJoons Posted March 25, 2021 Author Share Posted March 25, 2021 Thank you for your prompt reply. After following your advice re the info panel I think the image is not as transparent as I thought! Those pixels have RBG 0 but A 255, so I need to go back to the program that spat it out, which is where the issue will be. Not an affinity product that is doing that. The difficulty being that Affinity is the only program I have that can open exr, otherwise I suspect I would have noticed this sooner! Thank you for your help. David Quote Link to comment Share on other sites More sharing options...
NotMyFault Posted March 25, 2021 Share Posted March 25, 2021 Hi David, it would be very easy in Photo to automatically make those black pixel fully transparent, if only the background has black pixles. possible workflow: Invert Adjustment Threshhold adjustment so that only pure white pixels are shown in white, and all others in black rasterize to mask If there are a few pixels in wrong color, edit mask with black/ white brush Other option: use procedural texture filter with formula (basic concept, may need some tweaking): A=1-((1-R)*(1-G)*(1-B)*256-255) Quote Mac mini M1 A2348 | Windows 10 - AMD Ryzen 9 5900x - 32 GB RAM - Nvidia GTX 1080 LG34WK950U-W, calibrated to DCI-P3 with LG Calibration Studio / Spider 5 iPad Air Gen 5 (2022) A2589 Special interest into procedural texture filter, edit alpha channel, RGB/16 and RGB/32 color formats, stacking, finding root causes for misbehaving files, finding creative solutions for unsolvable tasks, finding bugs in Apps. My posts focus on technical aspects and leave out most of social grease like „maybe“, „in my opinion“, „I might be wrong“ etc. just add copy/paste all these softeners from this signature to make reading more comfortable for you. Otherwise I’m a fine person which respects you and everyone and wants to be respected. Link to comment Share on other sites More sharing options...
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