Simulate bitmap mode in photoshop for e-ink photo preparation

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I need to prepare some photos for an e-ink display.
The display is 1-bit. Each pixel is either 100% black or 100% white – there is no gray.

I know that I can change the mode of my photos in Photoshop to bitmap, and it will present a number of options as to how the dithering and noise are handled. But this process is destructive.

Is there a non-destructive way to simulate this in Photoshop?

I tried using the Halftone filter in Grayscale mode, but this makes circles instead of pixels, and doesn’t have any dithering options.

I can’t be the first person to need this – am I doing it wrong?

Adding some examples below.

I’m using an e-ink display from Waveshare. It’s 800×400 at approx 49 pixels/cm, 1-bit bitmap. So I’ve set up my Photoshop document like this:

8 bit grayscale:
grab1

I want to be able to try out different 1-bit bitmap “looks”, without destroying the original layer:

eg, Halftone screen settings like this:
enter image description here

gives this kind of result:
enter image description here

But a diffusion dither, gives a different look:

enter image description here

I would like to simulate all of these different looks in a grayscale document, without having to destructively edit my image each time.

I can use the Halftone Pattern filter on my original image, but it doesn’t offer the same settings as the 1 bit bitmap conversion, and looks different:

enter image description here

Answer

There is no Filter in Photoshop that simulates the different Bitmap mode methods.

You can’t really simulate any color mode with a filter (but Grayscale mode can of course be simulated by desaturating the image and CMYK mode can be simulated with Proof Colors).

You might think that you could convert your image to a Smart Object and then convert to Bitmap mode to retain the possibility to edit the original image and see the changes reflected in the bitmap version, but that’s not possible. Bitmap mode requires the image to be flattened.

This is unfortunate, and I sometimes feel Photoshop easily could have some possibilities to work non-destructively in Bitmap mode, but I guess it’s not a priority.

Idea for a workaround

If you want this non-destructive simulation in order to be able to dynamically finetune the conversion to Bitmap mode, I see no way. But if you are interested in quickly getting a preview of a specific conversion, I have this proposal:

  • In the Actions panel, Click Create new set to make a set of “Bitmap conversion preview” actions, click Create new action (optionally choose a Function Key, you can change this later) and click Record to start recording.
  • Select > All.
  • Edit > Copy Merged.
  • File > New. Click OK.
  • Edit > Paste.
  • Layer > Flatten Image.
  • Image > Mode > Bitmap.
  • Choose the desired Method. Click OK.
  • Select > All.
  • Edit > Copy.
  • File > Close. Click No.
  • Select > Deselect.
  • Edit > Paste.
  • In the Actions panel, Click Stop playing/recording to end the recording.

Now you have an action which will create a new layer with a bitmap version of your image with the chosen method. Run it from the Actions panel or use the specified Function Key. To remove the preview layer just Edit > Undo.

You can create actions for each Bitmap conversion method you want to be able to preview.

Attribution
Source : Link , Question Author : tomh , Answer Author : Wolff

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