If you've ever seen negative afterimage optical illusions, you know that they can be baffling and sometimes quite spectacular. They often involve staring at a negative image for 10-20 seconds and then looking at a blank space. The usual result is seeing what some call a "ghost image" of the negative image, yet it is seen as a positive image (i.e. the way it is supposed to look). These are a well understood retinal phenomenon.
This is a very simple project, yet it is extremely effective. The way that our eyes and brain perceive and interpret images allow for us to trick ourselves in this case. After viewing this over and over, the same effect happens each time. It can be frustrating in terms of trying to figure out why this illusion happens. Ultimately, it is my hope that you will find this helpful, intriguing, and boat-loads of fun!!
Here is a video of the completed project which shows the optical illusion in its entirety:
Step 1: What You Need
You will need:
1] A color photo file
2] Photo editing software that allows you to:
a) "invert colors" or create a "negative image" (almost all programs out there, including Paint, have this feature)
b) make a black and white version of the photo
3] Video editing software (this is optional but very helpful in yielding the best results)
Step 2: Choosing a Photo
I highly recommend using a photo that has rich colors and a lot of contrast. This will stimulate your eyes more and ultimately enhance the effect of the optical illusion.
Step 3: Creating a Negative Image
Import your chosen photo into a photo editing program. Then simply choose the "invert" (or "negative") editing option. This should convert the whole photo into a negative image. Then save it. Make sure that you keep the original color photo that you imported, if you want it. For instance, I used Photoshop and saved the inverted photo as a copy. I still retained the original photo.
Now, just like that, you have created the first part of the illusion.
Let's move on.....
Step 4: Creating a Black and White Image
Now that you have a negative color photo, it's time to create a black and white version of the original color photo. To do this, import the original color image into your editing program again. This time, just create a black and white version. Again, save it as a copy if you don't want to lose your original color picture file.
Step 5: Optional Focal Point
You probably noticed a dot near the center of the photos. This just provides a focal point that you can stare at in order for the full effect of the illusion to work.
It is not entirely necessary. Without it, you can just choose a point near the center of the photo to stare at. The important part is to stay "zoned in" on one spot near the middle of the picture.
If you decide to add a dot in your photos, use a drawing tool in your software to make a small white circle (see picture). Obviously when you invert the original color photo, this dot will be black. That's what you want.
Step 6: Bringing It All Together
1) Stare at the focal point of the inverted/negative color image for about 15 seconds.
2) Have the black and white photo appear, seamlessly, immediately after that 15 seconds.
3) Continue to stare at the focal point after this transition. You will see the black and white photo in color (unless you are colorblind)!
4) Keep your eyes on the photo, but switch your view to another part of the picture. Stunningly, you will see that it is black and white.
A video editing program is really helpful to use with this illusion. Just import all of the pictures into the editing program, except for the original color image. Drag the inverted/negative photo onto the timeline first and stretch it out so that it plays for about 15 seconds. Then drag the black and white version of the original photo onto the timeline and place it right next to that. Dont' get fancy and use any transition effects in between here. Just let it switch to black and white instantly. The amount of time that you keep the black and white photo playing is up to you, but I let it go for about 10-15 seconds or so.
Again, here is the full effect of the illusion in living color (or at least it appears to be):