dizzwave Posted January 27, 2021 Share Posted January 27, 2021 Hello, I think this is a bug but not 100% sure. In a nutshell, using the picker to create a curves node in a specific color channel (within the curves tool) does not place the node according to the color, but rather according to the overall luminosity. I'm using Affinity Photo 1.8.5.703 on Windows 10. I first noticed it with a photo I was editing in Lab Color mode, but I can repro with a fresh document with a simple color gradient. I've also reproduced it in RGB mode, but let me outline the steps in Lab mode: Create a new document. Convert to LAB Color mode. (I'm not sure if this matters.) Add a pixel layer, and fill it with a linear gradient going from {L=0 A=-128 B=127} on the left, to {L=100 A=127 B=-127} on the right (note the negative symbols). Add a Curves adjustment layer, and choose LAB from the first curves dropdown. Choose AOpponent from the second curves dropdown, and click Picker. Now, notice from my screenshots that if you use the Picker and drag from a point on the far right of the image, it adds a node to the curve. Note the LAB values of that pixel from the Info panel, and see that the A and B are complete opposites of each other. However, if you then do the same thing with the BOpponent selected, it adds the node to the same point in the curve. What I would expect here is that the node is added far to the right in the BOpponent curve, when the B is high for that pixel (and to the left when low).... and similarly for A. However, what appears to be happening is that it places the node based on the brightness (maybe the L value?) of the pixel, no matter what channel is selected in that second dropdown. I have attached my file so you can try yourself. Please let me know if I'm doing something wrong, or... if it's a bug, that would be great to know too! Thank you! :-) curvesGradientTest.afphoto Quote Link to comment Share on other sites More sharing options...
dizzwave Posted January 27, 2021 Author Share Posted January 27, 2021 Hello, me again.. This is an example of the expected/desired behavior, as shown in Photoshop. Thank you. Quote Link to comment Share on other sites More sharing options...
Staff MEB Posted March 19, 2021 Staff Share Posted March 19, 2021 Hi @dizzwave, Welcome to Affinity Forums Sorry for the delay getting back to you. We have been quite busy lately. I've logged this to be looked at. Thanks for your report. Quote A Guide to Learning Affinity Software Link to comment Share on other sites More sharing options...
dizzwave Posted March 19, 2021 Author Share Posted March 19, 2021 No problem, thank you for the update! Quote Link to comment Share on other sites More sharing options...
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