Value correction - Revision history

EricChadwick: removing class="wikitable"

2015-11-06T13:21:36Z

removing class="wikitable"

Caustic: Created page with "NOTOC = Value Correction = Value correction is a texturing method that allows you to remove problems in value variation..."

2014-10-11T16:17:53Z

Created page with "__NOTOC__  = Value Correction = Value correction is a texturing method that allows you to remove problems in value variation..."

New page

__NOTOC__

= Value Correction =
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.

== Lab Color Technique ==
The following Photoshop technique will help you remove value variation but retain the hue variation.

{| class="wikitable" style="width:512px;"
|Step 1: Here is a common source image, which looks ripe for usage as a texture!
|-
|[[image:value_correction_step1.jpg]]
|-
|Image from [http://www.cgtextures.com]
|}

{| class="wikitable" style="width:512px;"
|Step 2: Using Filter -> Other -> Offset reveals that there is uneven lighting in this image, making it difficult to tile. How unfortunate!
|-
|[[image:value_correction_step2.jpg]]
|-
|Image by [http://www.carlosmontero.com Carlos 'cman2k' Montero]
|}

{| class="wikitable" style="width:512px;"
|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!
|-
|[[image:value_correction_step3.jpg]]
|-
|Image by [http://www.carlosmontero.com Carlos 'cman2k' Montero]
|}

{| class="wikitable" style="width:512px;"
|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.
|-
|[[image:value_correction_step4.jpg]]
|-
|Image by [http://www.carlosmontero.com Carlos 'cman2k' Montero]
|}

{| class="wikitable" style="width:512px;"
|Step 5: Notice that much of your Value variation is now gone!
|-
|[[image:value_correction_step5.jpg]]
|-
|Image by [http://www.carlosmontero.com Carlos 'cman2k' Montero]
|}

{| class="wikitable" style="width:512px;"
|Step 6:Some standard clone-brushing helps you create a tiling texture like you normally would.
|-
|[[image:value_correction_step6.jpg]]
|-
|Image by [http://www.carlosmontero.com Carlos 'cman2k' Montero]
|}

{| class="wikitable" style="width:512px;"
|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.
|-
|[[image:value_correction_step7.jpg]]
|-
|Image by [http://www.carlosmontero.com Carlos 'cman2k' Montero]
|}

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.

Original thread: http://www.polycount.com/forum/showthread.php?p=1169603#post1169603

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[[Category:TextureTechnique]]

@@ Line 7: / Line 7: @@
 The following Photoshop technique will help you remove value variation but retain the hue variation.
-{| class="wikitable" style="width:512px;"
+{| border="1" style="width:512px;"
 |Step 1: Here is a common source image, which looks ripe for usage as a texture!
 |-
@@ Line 15: / Line 15: @@
 |}
-{| class="wikitable" style="width:512px;"
+{| border="1" style="width:512px;"
 |Step 2: Using Filter -> Other -> Offset reveals that there is uneven lighting in this image, making it difficult to tile. How unfortunate!
 |-
@@ Line 23: / Line 23: @@
 |}
-{| class="wikitable" style="width:512px;"
+{| border="1" style="width:512px;"
 |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!
 |-
@@ Line 31: / Line 31: @@
 |}
-{| class="wikitable" style="width:512px;"
+{| border="1" style="width:512px;"
 |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.
 |-
@@ Line 39: / Line 39: @@
 |}
-{| class="wikitable" style="width:512px;"
+{| border="1" style="width:512px;"
 |Step 5: Notice that much of your Value variation is now gone!
 |-
@@ Line 47: / Line 47: @@
 |}
-{| class="wikitable" style="width:512px;"
+{| border="1" style="width:512px;"
 |Step 6:Some standard clone-brushing helps you create a tiling texture like you normally would.
 |-
@@ Line 55: / Line 55: @@
 |}
-{| class="wikitable" style="width:512px;"
+{| border="1" style="width:512px;"
 |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.
 |-

Value correction - Revision history

EricChadwick: removing class="wikitable"

Caustic: Created page with "__NOTOC__ = Value Correction = Value correction is a texturing method that allows you to remove problems in value variation..."

Caustic: Created page with "NOTOC = Value Correction = Value correction is a texturing method that allows you to remove problems in value variation..."