After removing the background, the text color changes

[jueqing1015]

        Form1.PicImage.ColorFuzz = new ImageMagick.Percentage(20));
        Form1.PicImage.Settings.FillColor = Form1.PicImage.BackgroundColor;
        Form1.PicImage.Opaque(Form1.PicImage.BackgroundColor, MagickColors.White);

The final goal is to change the color of the background to white and deepen the color of the text

[dlemstra]

I don't understand what you are asking or telling me?

[dlemstra]

I suspect that you are doing something extra that changes the colors? With your sample code I am getting a completly different output image:

using var image = new MagickImage("input.jpg");
image.ColorFuzz = new Percentage(40); // had to increase this to get a similar image.
image.Settings.FillColor = image.BackgroundColor;
image.Opaque(image.BackgroundColor, MagickColors.White);
image.Write("output.jpg");

[jueqing1015]

Can you upload your output

[jueqing1015]

I tested using the code you provided, but the text color obviously changed.

[dlemstra]

The text color hasn't changed as much as you think it did. Due to to new background color the output looks different. And because you are saving your output image as a jpeg file the color while slightly change. When you examine the pixel at 332x263 you will see that the value changed from #2A3A76 to #293975. This really is a minor change. If you want to make sure you get the exact same color I would advise you to save the image as a png file instead.

[jueqing1015]

Thank you very much for your answer. I will try to save it as PNG in code to test it a bit