In a previous post I talked about why you might want to color reduce a design, even in the age of digital printing. In this post, I’ll go through the steps to color reduce a photo in Photoshop Elements. I’ll also note the differences for Photoshop since there are some variations.
The basic process is just a couple of steps:
- convert the photo to the ‘indexed color’ mode with 256 colors
- reduce the number of colors to around a couple dozen by picking the main colors from the photo
Steps for Color Reducing a Photo
1. Here’s the photo I’ll start with. Note that this photo is in RGB color mode. It’s always a good idea to work on a copy of your image and keep the original image unchanged.
2. The layer needs to be unlocked. Often when first opening a file, the layer will be locked (indicated by the padlock icon on the layer–circled here.) To unlock the layer, click on the padlock icon in the menu (arrow) and the padlock next to the layer will go away.
3. The next step is to convert the photo to what Photoshop calls the Indexed Color mode. If your file has multiple layers, they will be merged when you convert it to Indexed Color mode. From the menu, select the command Image–> Mode –> Indexed Color as shown below. This will bring up the pop-up box outlined in green below. Make sure the settings are set as follows:
- Palette–Local Adaptive
DO NOT CLICK OK.
3a. Without closing the “Indexed Color” pop-up box, click on the Palette drop-down list again and change the selection to Custom (see picture to the right). Note for Photoshop only: sometimes the “Custom” option is grayed out. If this happens, reselect “Local(Adaptive)” and change the number of colors (say to 255) and then change the Palette again to “Custom”.
4. This will open up a color table (shown to the right) with 256 colors from the photo. The photo has been reduced to these 256 colors, but we want to reduce the number of colors much further. Do NOT click OK.
5. Next is to select all the colors in this color table and change them to black. To do this, click on the color in the upper left corner of the color table, and drag your mouse down to the lower right corner so that all the color boxes are selected.
5a. This opens the color picker window shown here. Select black for the color, either by clicking in the lower left portion of the color window, or by typing 0 (zero) into the R and G and B boxes. Then click the OK button twice to close the color picker. Do NOT click OK to close the color table.
6. Now the Color Table is filled with black squares. We need to replace some of these black squares with the colors we’ll have in the final color-reduced image.
7. Click on one of the black squares in the color table, and the color picker window opens again. With the mouse, go the to main photo and click on one of the colors you want to keep. This color will then be in the color picker window.
7a. Click OK in the color picker window and the new color will replace the black square in the Color Table. Do NOT click OK to close the Color Table.
8. Repeat steps 7 and 7a to select additional colors from the photo. Using more colors gives a more accurate representation of the photo, but also makes changing colors later more work.
9. Here is the color table with 22 colors selected from the photo. When you think you’ve selected enough colors, click OK to close the Color Table. Since the Preview button was checked in step 3, this will show a preview of your color-reduced photo. Unfortunately, if you don’t like the results, the only thing to do is select Cancel and start over from the beginning. If you like the results, click OK and your photo is now color reduced, as shown below.
Note: In Photoshop Elements (and Photoshop) many image editing functions don’t work if your image is in Indexed Color mode. To make changes (other than swapping colors which is described below) you should change the image back to RGB color mode. This is done from the menu: Image–> Mode–> RGB Color, as shown below.
Swapping Colors in a Color-Reduced Photo
Now for the fun part…changing the colors.
1. If your file is back in RGB Color mode, first change it to Indexed Color mode: Image–> Mode–> Indexed Color. In the pop-up box, make sure the Palette is set to Exact (see picture on right) and click OK. Using Exact for your palette loads the colors which you picked when color-reducing the photo.
2. With the image in Indexed Color mode, open the color table: Image–> Mode–> Color Table, and the color table with your custom colors will pop up.
3. Make sure the Preview box in the Color Table pop-up is checked. Click on one of the colors in the Color Table that you’d like to change, and the color picker window opens. Select the new color and click OK.
4. With the Preview box checked, you’ll see the changes to your picture as you change the colors (see below). Repeat step 3, selecting additional colors to change until you’re satisfied with the result.
5. Here is the color table after I’ve changed all the flower colors to blues and purples, but I left the greens unchanged
And here is the Purple Daylily.
Here’s a comparison of the original photo (left), the color reduced photo and the re-colored photo.
“If you see a tree as blue, then make it blue.”– Paul Gauguin
“Oh, I love red. I”m very loyal to my colors. I love violet.”–Elizabeth Taylor