How to export a Monochrome image (not greyscale)

[Matt42]

I am trying to create an image which is in purely black and white, no shades of grey; How do I do this?

My ideas are:
- Make the rendering resolution of the document equal to the output resolution (1x) (disable antialiasing) -- Ideal solution
- Reduce the colour space to just black and white
- Some export option I haven't thought of

I have also tried the palettised export setting but that produces a lot of artefacts (below)

[R C-R]

The Affinity apps do not support monochrome (1 bit) images. You can disable antialiasing (so there are no grey edges) & use only pure black & pure white in your document, but it still will be a greyscale image.

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[telemax]

You can do this with Posterise Adjustment, with a minimum value of 2. Or as previously mentioned, by disabling antialiasing.
Posterise_Adjustment.afphoto
 

 

This can also be fine-tuned using the Coverage Map.

[David in Яuislip]

Try a gradient map. As for palletised png exports I have yet to find a use for the Affinity implementation, not being able to turn off dithering is, errrr, curious

[John Rostron]

You could also use a Threshold Adjustment (Layers > Adjustment Layer > Threshold).  Even this will get exported as a greyscale though.

John

[telemax]

Hmm, there's another way, just a rectangle with Contrast Negate blending mode.
Contrast_Negate.afphoto
 

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[Matt42]

4 hours ago, telemax said:

You can do this with Posterise Adjustment, with a minimum value of 2. Or as previously mentioned, by disabling antialiasing.
Posterise_Adjustment.afphoto
 

 

 

This can also be fine-tuned using the Coverage Map.

 

Thanks! This is exactly what I wanted

[R C-R]

4 hours ago, Matt42 said:

Thanks! This is exactly what I wanted

Note however that the Posterise_Adjustment.afphoto file is currently using the RGB/8 color format, & even if you change that to Grey/8, the export will still be in the greyscale color space.

[Fixx]

21 hours ago, R C-R said:

the export will still be in the greyscale color space.

unless you specify 1-bit format in export – that would be available in PNG and GIF formats. And they may produce dithering artifacts as you have noticed. 

Now we have closed the circle.

[R C-R]

1 hour ago, Fixx said:

unless you specify 1-bit format in export – that would be available in PNG and GIF formats.

Are you sure about that? Even when I specify a Black & White palette for a PNG or GIF export, I do not get a 1 bit export from any Affinity app.

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[R C-R]

23 minutes ago, Lagarto said:

They are technically 8-bit indexed (paletted) images with black and white colors defined, the other slots (total of 256) empty.

Yes, that is what I was referring to when I said they do not export as 1 bit images. 

[Matt42]

As much as I appreciate that the image is not being stored in 1-bit format, this isnt necessary for what I'm doing. Thanks for the help though.

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[Fixx]

13 hours ago, Lagarto said:

They are technically 8-bit indexed (paletted) images with black and white colors defined, the other slots (total of 256) empty.

That may be but hey still behave like 1-bit images. (I suspect the difference between 1-bit and indexed is not "architectural" but slight variation of the same format). They open as bitmap (1-bit) in Photoshop and behave like 1-bit in InDesign.

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[R C-R]

7 hours ago, Lagarto said:

It is possible to export a true 1-bit PNG from Affinity Photo...

Can you post an example of a true 1 bit PNG created in any Affinity app, & also explain what export settings you used to do this? AFAIK, the best Affinity can do is indexed color, with just two colors in its CLUT, not true one bit monochrome (A.K.A. binary) in which there are only two possible pixel values.

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[R C-R]

20 minutes ago, Lagarto said:

It was produced with the following settings:

Thanks for that. Yesterday, I tried doing the same thing with the same settings but for some inexplicable reason I kept getting PNG files that XnViewMP said were 8 bit. Today, the same settings produce PNGs that XnViewMP confirms are 1 bit & use a Black & White color model:

I have no idea why this was not working yesterday.

BTW, I also tried using Palletized set to Automatic & 2 colors & this also produces 1 bit Black & White color model PNGs according to XnViewMP. However, the PNG's this produces are not useable because everything not 100% transparent is pure black.

I have also been playing around with GIF exports using similar palletized settings & can also get GIF exports with 1 bit per pixel color depths, but with a "Color Resolution Depth" of 8, so I suppose that just means GIFs always can support up to 256 colors.

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[R C-R]

Regarding XnViewMP & using ExifTool to get more accurate info, as I understand it, XnViewMP uses ExifTool as a backend to read a lot of info.  So for example, your 1 bit yinyang from your last post shows this in the bottom half of the Info panel when the ExifTool tab is selected.

Two days ago, I assume I was doing something wrong when I tried to export using (among others) the same settings you showed & kept getting 8 bit PNGs. But like I said, yesterday everything was working as I assume it should & I could produce 1 bit PNGs & (I think) GIFs.

[wvanderzee]

Not a monochrome option in Photo? Pfff...