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I was wondering how I can do this type of optical illusion. Is it done manually or is there a quicker way to do it. Thanks ahead of time.

2 Answers 2


Simulate the old bw photo printing system. There dot sizes or line widths are modulated by local greyshades.

  • have a bw photo as a layer
  • have a pattern of black lines or dots on white. The pattern is your major line art and the printing raster at the same time. The illusion is the simulated greyshades.
  • blur the pattern. A slight zone of black and white should be left.
  • adjust the curves to get uniform shift from white to black in the blurred pattern
  • copy the blurred pattern to the layer mask of the photo, invert the mask!
  • insert a white background
  • make a safety copy of everything to be able to readjust and try again
  • merge the background and the masked photo
  • choose proper foreground and background colors in the tool palette; black and white are good.
  • go to image adjustment "Treshold"
  • adjust the treshold for your taste

Overlay your original pattern to make the line art dominant.

Here are a couple of examples. The line art is a bunch of horizontal straight lines. First a noisy smartphone photo is hidden into the "art"


In this example a second piece of art is hidden into the same horizontal line art:

Real art

  • 1
    I think this would benefit from an example... I struggled to follow this until I tried it myself
    – Cai
    Feb 11, 2017 at 16:06
  • Thank you so much user287001 for this answer. Though I also have some difficulties replicating this effect. Would you mind sharing a video with us? That would be really helpful! Thank you in advance. All the best, -J Feb 19, 2019 at 17:37

The way I do it:

You have to find a good photo of grayscale values.

Build your own Pattern before converting the image in Bitmap.

I used the Illustrator just to make the pattern.

The image below shows the step by step of the workflow.

enter image description here

  • good one! but why do you need to blur the pattern? Also wouldn't it give better results if the image would be B/W instead of greyscale to start with?
    – Luciano
    Feb 20, 2019 at 12:13
  • All the pattern sources need to be blurred. The PS bitmap conversion uses that gray information to make the reticulation process. If you do not do that, you will get just the lines you drew. Sometimes you have to convert the image to Grayscale before converting it to Bitmap. The Bitmap mode is enabled only in Multichannel and Grayscale modes.
    – LeoNas
    Feb 20, 2019 at 12:45

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