For the users of Photoshop software to share a detailed interpretation of the use of lab channels and brush tools to create a palette of the tutorial.
After using Photoshop for some time, many shadow friends will find that the software actually has two completely different uses. One is to use it to modify or improve the photo, and the other is to use it to draw the image from scratch. Either way, the difference is not that big, because they're all about pixel processing, regardless of whether the pixel comes from a digital image or a brush tool. In addition to the authenticity of journalistic photography, the comprehensive use of digital photography and digital painting technology to modify and image art processing, you can broaden the visual field of images. For the artistic post-processing of the photo, let's talk about how to use the lab channel and brush tools to create the palette.
Lab colors are an alternative color pattern between RGB and CMYK, and you must be unfamiliar with lab mode compared to the other two modes, because lab mode is not available for any actual output device. Lab functionality is not available in RGB and CMYK, it has the advantage of: first of all, Photoshop's internal color calculations are implemented through lab colors, and second, lab mode has the widest gamut, which provides a wider gamut than RGB and CMYK color spaces, while other modes are replaced with Lab mode , the color is not lost; Finally, lab is a color model based on the principle of human vision, which is very similar to the way people work, theoretically summarizing all the colors the human eye can see.
The lab's structure is comprised of the following 3 channels.
The L channel (or the "Lightness" channel) contains the brightness information, which is the black and white information that holds the image. A large part of the lab color's functionality stems from the separation of color information from brightness information.
A channel contains green and magenta information. At a given pixel point, a channel value of 0 indicates that the pixel is neither green nor magenta. In Photoshop, a channel value of 128 indicates that the pixel is completely green, and +127 indicates that the pixel is completely magenta. This color structure is called a confrontation color because the colors in the channel are at both ends of the color scale.
The B channel contains blue and yellow information. In Photoshop, when the B-channel value is 0 o'clock, the pixel is a neutral hue between yellow and blue. The 128 on the B-Channel scale represents pure blue and +127 is pure yellow.
As you can see, the lab color system has an opposing color channel, in A and B channels, 0 in the middle of the curve; negative numbers mean cool colors, positive numbers for warm colors, and color beyond the gamut of all output devices.
Dragonfly with Lab channel Palette
Ii. How to use lab colors for authoring
After familiar with the composition and working principle of lab color channel, we can create the artistic color palette of the photo. The general approach is to first convert the photo color mode to lab color; then copy the image, generate the copy image, and then in the copy image of the lab channel in the selection of "reversed", "tonal homogenization" command to achieve the overall color palette; Finally, drag the adjusted copy of the image to the original image, Become a layer of the original image, by creating a mask, using tools such as brushes to selectively draw, of course, you can also choose "blending mode" and adjust the layer's "opacity" to make the screen more subtle. Finish the work in the end.
In practice, the rendering and hardening of colors in the screen is often done through multiple lab channel palette and layer drawing overlay. Therefore, the use of lab to color the art of the image processing no fixed rules, visual and color feelings vary from person to person, the shadow friend in concrete practice can also be through more attempts to choose the most suitable for the film's color effect. The following image shows a variety of tonal effects, based on the original image, that are processed by "reverse-phase" and "tonal-homogenization" on each of the lab's channels. If the layers are combined with blending mode and brush tool, then the change will be infinite.
Original film: Flowers taken on a white background
Inverse of all lab channels: This adjustment produces an interesting effect opposite the color value of the datum image
Reverse the L Channel: Turn the white image black or turn the black image white
Reverse Phase A channel: add color to the image opposite to the green/magenta main hue
Reverse the B-channel: Add a color to the image that is the opposite of the blue/yellow main hue
Tonal homogenization of L channels: increases the contrast and special effects of images, and is suitable as a basis for new images
Tonal homogenization of a channel: adding green and magenta to the image
Tonal homogenization of B channels: add blue and yellow to the image
Inverse: Each pixel is replaced with its own opposite color. Black turns white, white to black. In lab colors, pure magenta will become pure green, and pure green will become pure magenta. Likewise, pure blue will turn into pure yellow, and pure yellow will become pure blue. Reverse-phase is very effective in lab mode, which is determined by the color antagonism structure of each color channel in lab mode, and you can reverse-process all channels or one channel. The visual effect of the image can be greatly enhanced by inverse phase. (Photoshop menu bar: image > Adjustment > Reverse)
Tonal homogenization: Tonal homogenization can maximize the color and contrast. When you do tonal homogenization, Photoshop collects the brightest pixels and turns them white, capturing the darkest pixels and turning them black. All values between the next two will be reassigned to the appropriate new value and extended in two directions. There is an interesting phenomenon in tonal homogenization of lab channels. If you consider the color antagonism of the lab channel, you will find that extending the range of values within the channel expands the range of colors within a channel, which can sometimes be useful. For example, a channel has a bit of green and a little magenta in different areas, so once the channel is tonal homogenization, more green and magenta will be generated in these areas. (Photoshop menu bar: image > Adjustment > Tonal homogenization)
Here are two specific examples to detail and demonstrate the specific methods and procedures for using lab palette. This process only represents the author's preference, the reader can understand the method of free creation.
Third, creative Lab color palette Case
Case 1: The Flower of Fantasy
A picture of a flower on a white background is generally seen as just a piece of plain material. I would like to use the lab method to color after making it based on the black background, while making the flowers have a magical color, petals with a strong sense of transparency and three-dimensional. Try it together.
1. Open a good white-bottom flower material in Photoshop. Copy the image from the menu bar "image > Copy" to open a new image window. Subsequent steps are based on the overlay of the layer superimposed on the original image and the lab channel palette of the copied image.
2. Change the copy image of the flower you just copied to the lab color mode. menu bar "image > Mode >lab color", the image is converted to lab color by RGB color mode.
3. Select the "Lightness" channel (L) in the channel panel so that the eye frame on the left side of the panel is visible and the other channels are not visible. Then the "brightness" channel to "reverse" operation, the menu bar "image > Adjust > Reverse" (or shortcut key command+i), and finally click the "Lab" channel before the eye frame to make all channels visible and selected. At this point you can see through the channel reversed phase, the image into a black bottom of the red flower.
4. In the original film white version of the upper right corner of the Panel open pop-up menu, select "Copy layer" to copy the layer to the black version of the image window, and named "White version." On the white version layer, hold down the ALT key while you click Add Layer mask below the layers panel to add a black full mask layer mask. Then use the White Brush tool to draw on the petals and then change the opacity to 20%, switching the layer blending mode to soft light, making the petals transparent and solid. Finally flatten all layers, menu bar "image > Flatten Images", leaving only the background layer.
5. Copy the original piece of the white version of the image in step 1 to the method of copying a new image window, named "Lab Reverse". After lab mode conversion, the lab is reversed by selecting all channels in the channel panel. Then, in step 4, copy the layer to the red flower Black bottom window.
6. Convert the color mode back to RGB color mode, menu bar "image > Mode >rgb color". (because partial blending mode cannot be used in Lab color mode). Change the blending mode in the layers panel to exclude, and then press and hold the ALT key while you click Add Layer mask below the layer panel to add a black full mask mask. Then use the brush tool to draw on the petals, and then change the opacity to 50%. This step can add a magical pink to the flower, with a livid color in the shadow, illuminating the center of the flower and certain petal regions.
7. Copy the background layer and drag it to the top of the layers panel. Then hold down the ALT key while you click Add Layer mask underneath the layers panel to add a black mask-masking layer. Change the blending mode in the layers panel to "overlay", then draw in the darker area of the screen, and then change the opacity to 45%. This step allows the flower to contrast the light and shade.
8. According to the above method continue to copy the original film white version of the image, the "brightness" channel reversed phase to produce safflower black bottom effect, and then to the brightness of the channel tonal homogenization. Then copy the layer to the main window. Press and hold the ALT key while you click Add Layer mask below the layers panel to add a black full mask layer mask. Change the blending mode in the layers panel to "soft Light", draw in the flower over area, and then change the opacity to 50%. This step can continue to enhance contrast and icing on the stereo, and make the flowers shiny.
9. Copy the original version of the white layer to the main window and continue adding a black layer mask. Change the blending mode in the layers panel to "filter", then draw in the Flower Center area, then change the opacity to 40%. This step will brighten the center area of the flower.
10. Flatten the image. Two times cutting composition, sharpening, get the final picture effect.
Case two: Gorgeous sea view
The same applies to landscape photography using lab-artistic rendering, which enhances color and scene effects in the image. The following scene is filmed in the Mediterranean, the original film is relatively flat, through the lab Channel Artistic palette, strengthen the gorgeous color of the sunrise, especially at sea wonderful Jesus light!
1. Open a sea view raw original image in Camera raw, and make basic adjustment to the original color temperature, highlight, shadow and other parameters. Then click Open Object to open the image in Photoshop.
2. Copy the image, menu bar "image > Copy", named "L Channel tonal homogenization", generate the image copy in the new window.
3. Converts the image mode of the new window copy to Lab color. menu bar "image > Mode >lab colors". Then select the "Lightness" channel (L) in the channel panel so that the eye frame on the left side of the panel is visible, and the other channels are not visible. Then the brightness channel for the "tonal" Operation, menu bar "image > Adjust > Tonal homogenization", and finally click the eye frame before the Lab channel to make all channels visible and selected. At this point you can see through the Brightness channel tonal homogenization, the image of the black and white layer strengthened.
4. Copy the image of the original window, the menu bar "image > Copy", named "a channel tonal homogenization", generate a copy of the image in the new window. In the same way as Step 2, the A-channel hue in the channel is uniformly formatted.
5. Copy the image of the original window again, the menu bar "image > Copy", named "B-Channel tonal homogenization", generate a copy of the image in the new window. In the same way as Step 2, the B-channel tones in the channel are uniformly formatted.
6. Switch to steps 3, 4, respectively, 5 image window, in the upper right corner of the layers Panel open pop-up menu, select "Copy layer" to copy the layer to the original image window, and then named "L Channel Tone homogenization", "a channel tonal homogenization", "B-Channel tonal homogenization." In the original image window, there are three new layers of lab channel rendering, in addition to the initial background layer.
7. Click on the left eye frame, the "A-channel tonal homogenization" and "B-Channel tonal homogenization" two layers of eyeball cancellation, so that the layer is not visible. When you hold down the ALT key on the layer "L channel tone homogenization" and click "Add Layer Mask" below the layers panel, add a layer mask with a black full mask. Then use the White Brush tool in the picture, decorate the cloud and the sea of black and white stereo relationship, the layer blending mode switch to "overlay", the opacity to 80%.
8. Click the eye frame on the left side of the "A-channel tonal homogenization" layer to make the layer visible. Press and hold the ALT key while you click Add Layer mask below the layers panel to add a black full mask layer mask. Then use the White Brush tool to draw the clouds and light positions in the screen, switch the layer blending mode to "lighten", and change the opacity to 90%.
9. Click the eye frame on the left side of the "B-Channel tonal homogenization" layer to make the layer visible. Press and hold the ALT key while you click Add Layer mask below the layers panel to add a black full mask layer mask. Then use the White Brush tool to draw the clouds and light positions in the screen, switch the layer blending mode to "overlay" and change the opacity to 75%. At this time the overall effect of the screen has been presented!
10. Brush the mask mask of each layer again to fine-tune, blending mode and transparency can be fine. Then flatten the image and sharpen the image. At this point the sky is a little light on the upper right corner, you can go to the menu bar "Filter >camera raw filter", using the "gradient filter" to darken the sky processing. The final image is saved after being determined.
Well, the above information is small compiled for you photoshop This software users of the detailed use of the lab channel and brush tools to create color palette of the full content of the program to share, you see the users here, Xiao Bian believe that you are now very clear the course of the bar, Hope that the small series of the above sharing of the tutorials can bring useful help.
