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| − | __NOTOC__
| + | #REDIRECT [[Value_correction]] |
| − | <!-- ## page was renamed from Value Correction -->
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| − | = Value Correction =
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| − | Value correction is a texturing method that allows you to remove problems in value variation from a source image. This is a common problem when trying to create tiling textures, and is often due to uneven lighting in the source image.
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| − | == Lab Color Technique ==
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| − | The following Photoshop technique will help you remove value variation but retain the hue variation.
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| − | {| class="wikitable" style="width:512px;"
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| − | |Step 1: Here is a common source image, which looks ripe for usage as a texture!
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| − | |[[image:value_correction_step1.jpg]]
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| − | |Image from [http://www.cgtextures.com]
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| − | |}
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| − | {| class="wikitable" style="width:512px;"
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| − | |Step 2: Using Filter -> Other -> Offset reveals that there is uneven lighting in this image, making it difficult to tile. How unfortunate!
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| − | |[[image:value_correction_step2.jpg]]
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| − | |Image by [http://www.carlosmontero.com Carlos 'cman2k' Montero]
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| − | |}
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| − | {| class="wikitable" style="width:512px;"
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| − | |Step 3: Go to Image -> Mode -> Lab Color. In your channels, notice that you now have a LIGHTNESS channel. select that channel and notice how you can see clearly how much value variation exists!
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| − | |[[image:value_correction_step3.jpg]]
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| − | |Image by [http://www.carlosmontero.com Carlos 'cman2k' Montero]
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| − | |}
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| − | {| class="wikitable" style="width:512px;"
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| − | |Step 4:Go to Filters -> Other -> High Pass and vary the amount until most of the lighting variation is gone. In addition, you can use dodge and burn in this mode to try and hand-fix value variation problems and try to get things as even as possible.
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| − | |[[image:value_correction_step4.jpg]]
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| − | |Image by [http://www.carlosmontero.com Carlos 'cman2k' Montero]
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| − | |}
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| − | {| class="wikitable" style="width:512px;"
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| − | |Step 5: Notice that much of your Value variation is now gone!
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| − | |[[image:value_correction_step5.jpg]]
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| − | |Image by [http://www.carlosmontero.com Carlos 'cman2k' Montero]
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| − | |}
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| − | {| class="wikitable" style="width:512px;"
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| − | |Step 6:Some standard clone-brushing helps you create a tiling texture like you normally would.
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| − | |[[image:value_correction_step6.jpg]]
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| − | |Image by [http://www.carlosmontero.com Carlos 'cman2k' Montero]
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| − | |}
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| − | {| class="wikitable" style="width:512px;"
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| − | |Step 7: Using Levels and Offset again shows that you have a wonderful tiling texture with very little tiling problems. As a happy side-effect, this technique also has a habit of subduing lighting information (shadows & highlights) which is great for dynamic lighting with normal maps and specular in most engines.
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| − | |[[image:value_correction_step7.jpg]]
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| − | |Image by [http://www.carlosmontero.com Carlos 'cman2k' Montero]
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| − | |}
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| − | Note: This is useful for removing contrast, but some of that contrast is good to have and you may not want to remove it all. Experiment with keeping a copy of image that hasn't been equalized in this way, and masking contrast back in only where you want it. For instance, you could make a value-equalized version and paint it in only over the seams you are trying to remove.
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| − | Original thread: http://www.polycount.com/forum/showthread.php?p=1169603#post1169603
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| − | ----
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| − | [[Category:TextureTechnique]] | + | |
