How was this image designed?

Question

I've just came across a image with a peculiar effect. I'm not sure how they have hidden the original image in the lines(or layer perhaps?)

There has been no visible changes in color nor in the pattern of lines. So, how exactly did they embed the original image between the lines?

And Is there any way I could achieve the same effect using Photoshop?

Image:

The hidden image can be viewed by a steady up and down scrolling

P.S. I'm a beginner in Photoshop.

Answer 1

There are some changes in color. Tts difficult to see with naked eyes but if you import you object to photoshop and use eyedroper you can see some color variations.

How you can achieve this effect:

1. Create the pattern(There are lots of ways to create this if you don't want to create this manually). You can change the color of upper and lower strips

1. Now put the image below the Patter (make sure the image is black) and Rasterize both (pattern and Image layer)
2. Now if you can see the original image, the pattern is little bit thicker where the panda shade lies. So, to do this, the easiest thing we can do is -
3. Select all the black region of your pattern [(CTRL + Click on the pattern layer thumbnail or Go to SELECT > Color Range > and select black color(increase the fuzziness to a higher value so it can select both shades of black)]
4. Now, Go to SELECT > MODIFY > EXPAND > and enter the value of 1px.
5. Now, Invert your selection (CTRL + SHIFT + I) go to the Image layer and hit Delete. It will delete all the unwanted area and will leave behind a thickness or 1px at the border. that's it.

Here's is my result

You can zoom out the image to see the proper result.

Note: Make sure you are creating this in high resolution(in my case I have created this in file size of 1350x1920px) So, 1px expansion worked for me.

Answer 2

The bars in the pattern are actually not of exactly the same width. Some bars are slightly thicker, adding a darker mean shade to the image in that location. This way the picture is visible by just a slightly darker mean color (like 50% brightness for the bright regions and 52% brightness for the darker regions).

You can do this in photoshop, if you start with a gradiented pattern, eg. you create the bar fence as smooth transitions between black and white instead of sharp bars.

You then blend the target picture over that with only some percent and merge it down, to have the soft pattern attenuated a little bit by the picture.

Last step is to use threshold to regain an b/w image.

As the blended picture modulated the brightness slightly, the threshold cut more or less of the bar width and so modulates the bar width.