Let it snow in the most unlikely of places, using Photoshop’s channels and layers.
The tricky thing about many outdoor-scene projects is that they’re often commissioned months before they’re used, meaning that you can find yourself trying to come up with summer scenes in chilly spring weather, or winter scenes in the height of summer.
This doesn’t have to be an impossible task, though – here, Jeff Huang shows how to convincingly fake a snowy scene using Photoshop channels, layers and careful painting.
01. Open Ruins.jpg from the cover disc in Photoshop. Rename the ‘Background’ layer to something else. For this instance, let’s name it ‘BG’. As well as helping keep the layers organized, this will also unlock the layer for you to work on.
02. To paint a truly convincing snow scene by hand, you’d need to be an excellent artist with a good knowledge of the properties of snow. Thanks to Photoshop, this is considerably easier to create digitally: we’re going to start creating our scene by exploring one of Photoshop’s most useful tools, Channels. Go and click into the Channels menu to display the Red, Green, and Blue channels.
03. Cycle through the channels to find the one with the most white displayed on the tops of the ruins. This is because snow typically lands on the tops of structures. Here, the Blue channel is the one we want to deal with because it reflects the sky, and the sky’s colours are usually reflected onto the tops of shapes. So, let’s right-click on the Blue channel and duplicate it. Rename this new channel ‘Snow1’.
04. Because we’re going to use this channel to make a selection for our snow, we want it to be as precise and clean as possible, so we’re going to do a curve on this channel. With the channel selected, hit Cmd/Ctrl + M to open the curves window. Click anywhere on the curve to make a point, then change its Output to 227, Input to 154. Click again to create a second point, and change its Output to 33, Input to 48.
05. Now Cmd/Ctrl + Click on the ‘Snow1’ channel to create a selection. With the selection still up, go back to the Layers menu and create a new layer (Cmd/Ctrl + Shift + Alt + N). Click on the colour picker’s primary colour from the tool bar, and input the # colour as e6e6e6. Now with this Light Grey colour, hit Alt + Backspace to fill the selection into the newly created layer. Finally, deselect the selection by hitting Cmd/Ctrl + D or clicking outside the canvas.
06. Rename this snow layer, ‘SnowLayer1’. If you’ve followed the previous steps properly, you should already have a fairly convincing snow scene – but we’re not done yet! The trees and bushes still look as if they haven’t been snowed on. So we’re going to try the same channel technique, this time to extract from the green. Go back to the Channels menu, duplicate the Green channel and rename the new channel ‘Snow2’.
07. With the channel selected, hit Cmd/Ctrl + M to bring up the Curves menu. Click on the curve to create a point and change its Output to 135, and its Input to 91. Click again to create a second point and change its Output to 51, Input to 43.
08. Now Cmd/Ctrl + Click on the ‘Snow2’ channel to create a selection. With the selection still up, go back to the Layers menu and create a new layer. Hit Alt + Backspace to fill the selection into the newly created layer with the same Light Grey colour from before. Deselect the selection. Rename this new layer ‘SnowLayer2’. Add a layer mask for this layer and fill the mask with pure black so that the content in ‘SnowLayer2’ disappears from the canvas.
09. The reason we first masked out ‘SnowLayer2’ is because we only want the snow to appear at certain areas. Take a large soft brush, and begin to paint white into trees and bushes to reveal snow in those areas only. Vary the brush size and opacity to help paint in small areas and to fix overlapping snow that may be outside the trees and bushes. Remember that it’s impossible to mess up here: you can simply paint black back into the mask to fix areas where needed.
10. For this step, we’re going to paint again in ‘SnowLayer2’, creating snow on the sides of the ruins that currently have no snow. It’s hardly convincing that such a snowy scene would have parts of the ruins without snow. Therefore, we’re going to paint in a convincing amount of snow in these areas. Remember to vary brush size and opacity for desired results.
11. We now have the base of our winter transformation done. Let’s add a little detailing by introducing some real snow to the canvas. Open SnowStock.jpg from the cover CD and drag the image into your tutorial workspace. Place it on the lower right hand corner of the canvas. Rename this layer ‘SnowDetail’ and add a layer mask to the layer.
12. Again, fill the mask with pure black first to mask out the entire layer. With a soft brush at a low opacity (around 25%), begin painting in snow in the open area. The goal is to create a convincing area of snow, enhancing the illusion that it’s snowing. Paint only enough to be convincing – don’t overdo it or the snow will stand out from the rest of the scene and end up damaging the realism.
13. You might have noticed that the colour of the snow we’ve just added doesn’t match that in the rest of the scene. To fix this, select the layer ‘SnowDetail’ and hit Cmd/Ctrl + U to bring up the Hue/Saturation adjustment menu. In the Hue section, input the value of -180. The colour should now be much more convincing, but we’re not done yet. Hit Cmd/Ctrl + L to bring up the Levels adjustment menu and change the input values to: 40, 1.00, 245, and hit apply.
14. Next, we’ll make this a convincing snow scene is by adding snowfall. Open Snowfall1.jpg and Snowfall2.jpg from the cover CD. Hold Shift, and drag each of the two snowfall images into our tutorial (holding Shift plots them perfectly onto our canvas). These images have snow, but also totally black backgrounds. Don’t panic! Change the blending mode of these layers to Screen and you will now only see the snowfall through the canvas. Rename these two layers to ‘Snowfall1’ and ‘Snowfall2’ respectively.
15. There isn’t enough snowfall yet. Duplicate the ‘Snowfall2’ layer once, then hit Cmd/Ctrl + T to bring up Free Transform. Right-click (Cmd + Click) and select Rotate Vertically. Now rename this new layer ‘Snowfall3’. There should be a convincing amount of snowfall now. To enhance the natural look of these snowfall layers, change and vary the opacity in each layer – ‘Snowfall1’ to 35%, ‘Snowfall2’ to 50% and ‘Snowfall3’ to 90%.
16. In the final step, we’re going to make final overall adjustments by creating adjustment layers. First create a Hue/Saturation adjustment layer and change its Saturation input to “-15”. Then create a Color Balance adjustment layer and change the Midtones RGB values to R: -5, G: 0, B: +5. Then go to the Highlight RGB values and change them to R: 5, G: 0, B: +5 as well. Finally, go to the Shadows RGB values and change them to R: 0, G: 0, B:+5. You’ve now turned this summer scene into a chilly winter’s day.
Another quick use for channels is separating plain backgrounds from images. A simple way to use channels for this is: go to Select > Color Range, and then use the Eyedropper tool to select the background colour. If there are several colours in your background, click on the eyedropper with the ‘+’ sign to add in more colours to your selection. Click on the Channels palette, and click the ‘Save Selection’ button at the bottom. Your background is now in its own channel and can be turned on or off, or altered.
Who: New York-based Jeff Huang is a 21-yearold graphic artist and illustrator, who specializes in digital illustration and print design but also has experience of 3D modelling, animation, motion graphics and compositing. He’s been working as a digital artist for three years, and has a style that name-checks graffiti, surrealism, digital matte painting and 2D illustration.
Software: Adobe Photoshop CS3
Time to complete: 1-2 hours
On the CD: All files for this tutorial can be found on the cover CD.