Merging single colour images in photoshop

This method describes a process for creating red and green merged images using Photoshop ver 6.0.

1.    In Photoshop, open the files that you wish to merge. Note that each image should be the same size.

a.   If the files are Bio-Rad .PIC files, see Opening Biorad PIC files in Photoshop for how to open the files without first converting them to another format.)

b.   If the files are colour images (but look black and white), convert them to greyscale images: Go to the "Image, Mode" menu and click on "grayscale". You might get a message about discarding colour information; say "yes". Do this for each image you wish to merge.)

2.     Make sure that your background colour is black. ("Tools" palette, click on "set background color". Make sure "R", "G" and "B" are set to zero and "#" reads "000000".)

3.     Create a new RGB colour image with a black background: "File, New." Enter the width and height of your new image (should be the same as the images you have already opened). Make sure the "Mode" is "RGB color" and the "Contents" area has "background color" selected. Click "OK".

4.     Make sure the "Channels" palette is open. (If not, go to the Window menu and click on "Show Channels".) Type "Ctrl+1" or click on the word "Red" in the channels palette. The background colour in this palette should disappear from all but the red channel.

5.     Click on the grayscale image that you opened which you wish to be shown as the red colour in your final image. Type "Ctrl+a" (select all), "Ctrl+c (copy).

6.     Click on the new image. Type "Ctrl+v (paste).

7.     Type "Ctrl+2" or click on the word "Green" in the channels palette. The background colour in this palette should disappear from all but the green channel.

8.     Click on the grayscale image that you opened which you wish to be shown as the green colour in your final image. Type "Ctrl+a" (select all), "Ctrl+c (copy).

9.     Click on the new image. Type "Ctrl+v (paste).

10.  Type "Ctrl+~" or click on the word "RGB" in the channels palette to see the final image.

11. Save the image.

Notes:

a.     This is only one way of producing a red and green merged image. The same principle may be applied to creating red/blue and green/blue images.

b.     To create a 3 colour red, green and blue merged image, simply additionally paste a grayscale image into the "Blue" channel.

The document is available to download as a pdf: