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I am trying to achieve this effect, a sort of randomized halftone. Is there a way to reproduce that in photoshop or illustrator ? The picture is from Huaman Studio (Barcelona, Spain).enter image description here

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    That's more pointillist than half-tone. The dots are all the same size & in the darker areas actually overlap. I've a friend who draws like that, with nothing but a Rotring pen… & a steady hand. Photoshop has a Pointillise filter, but I've never found it convincing.
    – Tetsujin
    Sep 27, 2023 at 16:37
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    The actual technique is probably more appropriately called stippling. I have never done it, but it may be achievable by posterizing a greyscale image to a manageable number of grey levels; making a set of brush patterns with progressively denser dot distribution that match the grey levels; and then applying pattern fill to the grey levels. An ascii art generator set to render with only a single unicode bullet as the glyph set might work too
    – Yorik
    Sep 27, 2023 at 16:46
  • Check out ( observablehq.com/@jobleonard/untitled )
    – Yorik
    Sep 27, 2023 at 16:50
  • Thanks Yorik for your answer. Your suggestion was my first idea but with this technique, the dots close to the edge of each region will be amputated. As you can see on the example picture, no dots are amputated. Also this technique will produce rasters instead of clean vector. this video show it, and as you can see it's not exactly what I am trying to achieve here : youtube.com/watch?v=C3a6mfFOLhs
    – Brice
    Sep 27, 2023 at 17:01

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If you use both Photoshop and illustrator, you get something like this quite easily (no plugins, no programming):

enter image description here

The result contains equally sized black vector circles which do not overlap, like the zoomed in snippet in the left shows. They are unfortunately in straight rows and columns. In your example the circles are placed more irregularly. The apparent irregularity gives optimization possibilities which makes the image look sharper for a given dot size. In addition watcher's eyes are not teased to follow dot rows instead of image forms.

For Illustrator there's available Astute Graphics plugin named Stipplism, which makes the vector version from a photo just as shown in your example. I do not have it. It belongs to a commercial filter packakge, but Astute probably gives a trial if one asks.

The procedure to make the "circles in straight lines" version without plugins:

  1. Adjust your photo to Grayscale, use curves so that the brightness scale covers the whole range from black to white.

  2. Change the image color mode to Bitmap > Diffusion Dither (must be Grayscale at first). Select so low pixels per inch -density that the image becomes only 100...150 pixels wide. The result has already the effect, but one dot is one square pixel:

enter image description here

  1. Change the image back to Grayscale or RGB. Paste it to Illustrator. Check in Photoshop the pixel dimensions (Width and Height as pixels) of the image. You must know them exactly.

  2. In Illustrator apply to the pasted photo Object > Create Object Mosaic. Let it be grayscale. Select the same number of rows and columns as which are the pixel dimensions of the photo.

If WxH is for example 100 x 150 the result will have 15000 squares. A low spec or already heavily loaded machine can crash.

  1. Ungroup and ungroup again until all squares are separate free objects. Select one white square. Check its width in the info line. You need that number soon.

  2. Select and delete all white squares by applying Select > Same > Same fill color, press DEL. The machine loading is reduced substantially.

  3. Select all remaining (black) squares. Apply to them effect Stylize > Round Corners. Let the rounding radius be a half of the square side length. The dots become circles. Expanding the the effect (Object > Expand Appearance) will reduce the machine loading.

The same effect as you want or a variation with colored or varying size circles has been asked numerous times in GDSE. Stipplism is presented as a vector solution and Diffusion Dither (or it's equivalent in GIMP or Krita,) is presented as a bitmap Solution. Other suggestions are rare. Make a web search for "stipple generator" and "halftoning software" to get other options. Typing into GDSE search word "Stipplism" shows also a few alternatives.

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  • Yorik answer seems to be a very promising tool for achieving what I am looking for observablehq.com/@jobleonard/untitled. However, I cannot manage to see nor download the full generated picture (even with the default set). Would it be possible to explain here the procedure ? Thanks in advance :)
    – Brice
    Sep 27, 2023 at 17:26
  • @Brice The linked story is not a ready to use tool, but a presentation of programming experiments. You can select the test picture from a preset collection and set parameters to see their effect. Only remember also to start each processing phase. I guess you have tried to find the next two buttons: 1) input your own image 2) save the processing result as a vector to your computer. The selector for your own image exists. But save as vector doesn't. You can save only the resulted bitmap like web images in the browser normally can be saved (right click). Sep 28, 2023 at 10:49
  • @Brice (continued) The easily available results are rasterized to PNGs and have bad anti-aliasing blurriness. But all processing is said to happen in the browser, so in theory a programmer could make some code reverse engineering and find where to catch the vector version from. It needs professional programming skills. The result even from the "fixed size black dots on white" is superior (tried it) when compared to my "dots in straight lines" version with as many dots. Of course, I have only the PNG. Sep 28, 2023 at 11:20

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