Convert image to black and white


#1

Am I the only user who exclusively wireframes in black and white?

I do fairly high fidelity wireframes, but I want my clients to know the are not design files, keeping everything in B&W is a great way to make it totally clear.

I’d love to be able to convert pasted images into B&W right in Omni. Is this possible already?


#3

There aren’t any filters in OmniGraffle, but you could try exporting to PDF and use the Black and White quartz filter in Preview to convert. You could also export as SVG or copy as SVG, then add a grayscale filter as described in https://www.hongkiat.com/blog/grayscale-image-web/ to get the results you are looking for. Otherwise, something could be possible with scripting if you have OmniGraffle Pro, but there is no filter or convert to Black and White option currently.


#4

If I were you, I’d first open the image in Preview*, then use Tools: Adjust Color (Cmd-Alt-C) and drag to Saturation to 0. Then just Cmd-C again, and paste into OmniGraffle.

* Launch Preview, then Cmd-N to open the image that’s on the clipboard.


#5

Hello all, here’s an interesting trick that Omni wrote back with.

  1. Use Preview to quickly convert an image to grayscale before adding it to your canvas. To do that:
  • Open the image in Preview
  • If you’ve just copied an image you can open Preview and use the shortcut to Command-N to open the copied image.
  • Then use Tools > Adjust Color… to make your desired change
  • Use Command-A to select the whole image, then Command-C to copy
  • Now paste into OmniGraffle
  1. If you already have an image in OmniGraffle, you can draw another shape on top of it, that will desaturate the image. Here is how:
  • Have an embedded image already on your canvas
  • Draw a new rectangle with a Solid Fill color of black
  • Under the color swatches, click the dropdown item that says “Normal”, and set it to “Color”
  • Move this rectangle over the image on your canvas, and you’ll see any part of the image covered by this new shape is now grayscale

#6

Thanks for sharing your findings! It might be worth knowing that solution 2 is great if it appearing desaturated is all that you need. If you need to resulting image to not contain that color information after export, solution 1 might be the better choice.


#7

Hello,
As I read you want to convert image to black and white.
If you work in the OmniGraffle then you have to follow these steps:

  1. You have to put your image on the canvas

  2. Draw a new parallelogram with a Solid Fill colour of black

  3. Now under the colour swatches, click the dropdown item that says “Normal” and set it to “Color”

  4. Then you have to move this parallelogram over the image on your canvas, and you’ll see the image convert black and white.
    Hope this will help you.
    Thanks