storrya Posted October 13, 2023 Posted October 13, 2023 When adding a black and white layer, with a view to then adjusting the brightness of the tones in the ‘colours’ via the properties box, has anyone noticed that for some colours, grain (or noise) is added to the image as a result. my raw images are iso 64 and prior to adding the b/w layer, no other adjustments have been made. has anybody else experienced this ? I also see it in photoshop so it’s not a bug in affinity photo. cheers. Quote
NotMyFault Posted October 13, 2023 Posted October 13, 2023 Hi, can you upload an example image? And try to switch the language in affinity to "English", so we are able to exactly see what adjustments you are doing (in screenshots). 5 hours ago, storrya said: When adding a black and white layer Do you mean black and white adjustment layer? 5 hours ago, storrya said: then adjusting the brightness of the tones in the ‘colours’ via the properties box, Adjusting brightness will alter the color values. In case of an RBG/8 image, you will always get some banding and rounding. 5 hours ago, storrya said: has anyone noticed that for some colours, grain (or noise) is added to the image as a result When you brighten up dark areas, the colors will become unnatural. Dark colors have only very few bit to encode lightness values, and even small adjustments will cause strong changes, amplifying noise. Try this with RGB/8 document take a good image, and reduce brightness by 1/8. Merge visible Increase brightness *8 the image quality will be visibly reduced from original. If you do the same with RGB/16, the difference will be unnoticeable. walt.farrell 1 Quote Mac mini M1 A2348 | MBP M3 Windows 11 - AMD Ryzen 9 5900x - 32 GB RAM - Nvidia GTX 1080 LG34WK950U-W, calibrated to DCI-P3 with LG Calibration Studio / Spider 5 | Dell 27“ 4K 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. I use iPad screenshots and videos even in the Desktop section of the forum when I expect no relevant difference.
walt.farrell Posted October 13, 2023 Posted October 13, 2023 31 minutes ago, NotMyFault said: Try this with RGB/8 document take a good image, and reduce brightness by 1/8. Merge visible Increase brightness *8 the image quality will be visibly reduced from original. If you do the same with RGB/8, the difference will be unnoticeable. Did you mean RGB/16 for the second one? NotMyFault 1 Quote -- Walt Designer, Photo, and Publisher V1 and V2 at latest retail and beta releases PC: Desktop: Windows 11 Pro 23H2, 64GB memory, AMD Ryzen 9 5900 12-Core @ 3.00 GHz, NVIDIA GeForce RTX 3090 Laptop: Windows 11 Pro 23H2, 32GB memory, Intel Core i7-10750H @ 2.60GHz, Intel UHD Graphics Comet Lake GT2 and NVIDIA GeForce RTX 3070 Laptop GPU. Laptop 2: Windows 11 Pro 24H2, 16GB memory, Snapdragon(R) X Elite - X1E80100 - Qualcomm(R) Oryon(TM) 12 Core CPU 4.01 GHz, Qualcomm(R) Adreno(TM) X1-85 GPU iPad: iPad Pro M1, 12.9": iPadOS 18.5, Apple Pencil 2, Magic Keyboard Mac: 2023 M2 MacBook Air 15", 16GB memory, macOS Sequoia 15.5
NotMyFault Posted October 13, 2023 Posted October 13, 2023 1 minute ago, walt.farrell said: Did you mean RGB/16 for the second one? Yes, now corrected. Thank you Quote Mac mini M1 A2348 | MBP M3 Windows 11 - AMD Ryzen 9 5900x - 32 GB RAM - Nvidia GTX 1080 LG34WK950U-W, calibrated to DCI-P3 with LG Calibration Studio / Spider 5 | Dell 27“ 4K 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. I use iPad screenshots and videos even in the Desktop section of the forum when I expect no relevant difference.
lepr Posted October 14, 2023 Posted October 14, 2023 16 hours ago, storrya said: my raw images are iso 64 and prior to adding the b/w layer, no other adjustments have been made Please clarify whether you mean the B&W section of the Tones tab of the Develop Persona or a B&W Adjustment Layer in the Photo Persona. Quote
storrya Posted October 14, 2023 Author Posted October 14, 2023 Some answers, hopefully for everyone… yes, black and white adjustment layer. RGB image 16 bit clarifying that it is bw adjustment in photo persona and not develop persona Hope this helps further. you could be right that it is the brightening of darker tones causing the problem. Lightning or darkening of light tones is probably ok . I will investigate Quote
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