Ok, so my code is working fine - I can manipulate the colours however I want. But which colours do I change??

I've used xxd to look at common pixels, I've tried bring some out in different combinations, but I can't get the combo right! I can kinda see an image (and if I tilt my screen I can see who it is, but that's besides the point!). This is less about the code and more about manipulating colours, but I'd like to know as it's driving me crazy.


Google "hexadecimal grayscale values" -- w3schools.com will have the best tip of all, if you think about it for a minute.

EDIT: Hexadecimal Colors: Shades of Gray

It might seem counter-intuitive, but the best way to "get the red out" of the image is to leave the red value untouched, and do something to the green and blue values instead.

By the way, if this helps, please click the green check mark to protect our forum against undead "zombie questions!"


You have the right approach. Look at the pixels using xxd and you should easily see that the majority are the same.

Remembering the format of each pixel has two hex digits for red, green and blue you can see through xxd which pixels are red.

Then you can edit these pixels to reveal the image.

Hope this helps.

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