Photoshop: Changing RGB images to Black and white via Channel mixer

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  • Updated 7 years ago
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When adding a Channel mixer layer and to a CMYK image I can turn it into a monochrome image and then output a black image from indesign however I cannot do this with an RGB image even though the option is the same Channel mixer - monochrome checked. Can this be fixed so monochrome become real monochrome images even for RGB images via channel mixer inside Indesign?
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Patrik Bloebaum

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Posted 7 years ago

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Chris Cox

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No, the channel mixer adjustment cannot change the mode of the document.
After you have applied the adjustment, you can convert the document to grayscale mode, then save it.
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Michael Orts, Employee

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Hi Patrik,

I'm not familiar with the In Design workflow but maybe I can still help.

Are you saying you'd like to output a grayscale image using the settings applied to the RGB image with Channel Mixer? To do this you can use the menu command Image > Mode > Grayscale and when prompted choose to flatten (if using the channel mixer adjustment layer) and then choose to discard the color information. If you're looking to output a cmyk image you can just make the same adjustment and use the menu command Image > Mode > CMYK.

Does this help, or are you looking for something different?