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lauren@photoboothsupplyco.com  
#1 Posted : Saturday, October 28, 2017 2:27:03 PM(UTC)
lauren@photoboothsupplyco.com

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Joined: 7/30/2017(UTC)
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I'm trying to apply a brightness and contrast to an image and I'm not sure if I'm doing it right.

I already have an image loaded in a bitmap and from the sample code I saw where I have to create a new Brightness and Contrast object and then apply the values based on those objects. Here is my code:

Code:


    resizedBmp.Transforms.Resize(new Size(width, height), ResizeInterpolationMode.Medium, ResizeMode.ImageFill);

    using (var brightness = new Brightness())
    using (var contrast = new Contrast())
    {
        brightness.Auto = false;
        brightness.Amount = 0.3f;

        contrast.Auto = false;
        contrast.Amount = 0.15f;

        using (var brightnessBitmap = brightness.Apply(resizedBmp))
        {
            Aurigma.GraphicsMill.Bitmap finalBitmap = contrast.Apply(brightnessBitmap);

            var jpegSettings = new Aurigma.GraphicsMill.Codecs.JpegSettings();
            jpegSettings.Quality = 90;
            jpegSettings.UseSubsampling = false;
            jpegSettings.IsProgressive = true;

            finalBitmap.Save(filename, jpegSettings);

            finalBitmap.Dispose();
        }
    }

The issue I'm seeing is if I put in values of 0 for both Brightness and Contrast the image is looking washed out versus if I don't apply them at all.

Edited by moderator Sunday, October 29, 2017 9:26:37 PM(UTC)  | Reason: Not specified

Andrey Semenov  
#2 Posted : Sunday, October 29, 2017 9:25:43 PM(UTC)
Andrey Semenov

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Joined: 7/4/2017(UTC)
Posts: 33

Was thanked: 10 time(s) in 10 post(s)
Hi,

I believe the reason why output images are looking washing out is ResizeInterpolationMode.Medium. Please try Lanczos3 and compare results. I've testes this with 0 for Brightness and Contrast, and it works as expected.

Also, you can use shorter code to apply brightness and contrast, like below:

Code:
resizedBmp.Transforms.Resize(new Size(width, height), ResizeInterpolationMode.Lanczos3, ResizeMode.ImageFill);
resizedBmp.ColorAdjustment.Brightness(0.3f);
resizedBmp.ColorAdjustment.Contrast(0.15f);
...

Regards,

Andrew

thanks 1 user thanked Andrey Semenov for this useful post.
lauren@photoboothsupplyco.com on 10/30/2017(UTC)
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