kenh000 Posted November 23, 2019 Share Posted November 23, 2019 Hi. I am currently evaluating Affinity Photo to use with Astrophotography. I was hoping someone could help me with some basic questions. Imagine a photo of the night sky. A few stars but mostly 'dark sky'. The dark sky is far from black due to light pollution and other effects and often has a reddish or other color hue to it. To put it in terms of RGB think something like R: 90, G: 75, B: 78. I want to neutralize and darken the sky - something like R: 35, G: 35, B:35. I know how to do this in Photoshop (use the black point adjustment tool in Curves) but from poking around in the software and forums that feature is not yet available in AP. If I try to adjust the RGB values for the entire image, the stars also get impacted. So, how would I go about doing this in AP? My thought is to create a layer with just the stars on it and another layer with just the sky background. I could then manipulate the RGB values of the sky layer without impacting the star and then re-merge the layers. I have no idea how to select the stars and put on a layer and select the sky to put on another layer. How do I do these things in AP? Does any one have a better suggestion on how to accomplish this? Thanks. Ken Quote Link to comment Share on other sites More sharing options...
h_d Posted November 23, 2019 Share Posted November 23, 2019 Hi and welcome! I've only tried this with an "artificial" sky field set to your colour spec (R90 G75 B78), but a Brightness and Contrast adjustment layer with the blend mode set to Colour Burn may do the trick: Screen Recording 2019-11-23 at 16.15.43.mov I suspect there are lots of other ways... Quote Affinity Photo 2.0.3, Affinity Designer 2.0.3, Affinity Publisher 2.0.3, Mac OSX 13, 2018 MacBook Pro 15" Intel. Link to comment Share on other sites More sharing options...
smadell Posted November 23, 2019 Share Posted November 23, 2019 The easiest way I can think of is by using Luminosity masking, or by fiddling with the Blend Options directly. In brief, you can take your dark-sky-and-stars layer, duplicate it, and use Blend Options (click the Gear icon at the top of the Layers panel) to limit each of these layers to the dark areas or the light areas, respectively. Quote Affinity Photo 2, Affinity Publisher 2, Affinity Designer 2 (latest retail versions) - desktop & iPad Culling - FastRawViewer; Raw Developer - Capture One Pro; Asset Management - Photo Supreme Mac Studio with M2 Max (2023}; 64 GB RAM; macOS 13 (Ventura); Mac Studio Display - iPad Air 4th Gen; iPadOS 17 Link to comment Share on other sites More sharing options...
walt.farrell Posted November 23, 2019 Share Posted November 23, 2019 Welcome to the Serif Affinity forum, Ken. It would help to have a sample image. You should be able to attach a PNG image to another post so we have something to experiment with. But you can adjust the black point, though it's done differently than with PS. And this has been discussed at least once before. Perhaps something here will help, as it shows the use of Curves or Levels in an astrophotography context in AP: The AP Help for the Levels Adjustment also has some useful information. Quote -- Walt Designer, Photo, and Publisher V1 and V2 at latest retail and beta releases PC: Desktop: Windows 11 Pro, version 23H2, 64GB memory, AMD Ryzen 9 5900 12-Core @ 3.00 GHz, NVIDIA GeForce RTX 3090 Laptop: Windows 11 Pro, version 23H2, 32GB memory, Intel Core i7-10750H @ 2.60GHz, Intel UHD Graphics Comet Lake GT2 and NVIDIA GeForce RTX 3070 Laptop GPU. iPad: iPad Pro M1, 12.9": iPadOS 17.4.1, Apple Pencil 2, Magic Keyboard Mac: 2023 M2 MacBook Air 15", 16GB memory, macOS Sonoma 14.4.1 Link to comment Share on other sites More sharing options...
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