Colour displaying incorrectly?

From what I can tell, colours in Unreal are displayed differently from other applications (browsers, image editing software etc.) Not only does it appear different in the colour-picker box but on the lit surface as well.

I am trying to create a material that shows off the effects of a normal map. For this I want only a solid colour and not a texture.

I have made a program that creates a normal map from a texture, it also tells me the most common colour in the image. (I didn’t use the average colour as that appeared washed out, since the R, G, and B values were too close together.) So the accuracy of the displayed colour is quite important to me.

Here is an image demonstrating the issue:

The RGB values input are the same (with some rounding), but the colour shown in Unreal is actually (216, 120, 152) according to Photoshop.

I don’t really want to fix this by-eye as I am trying to follow a set method for each time I do this - I don’t want to have to apply a “random correction constant”.

If anyone knows what causes this or how to fix it, I’d be grateful for your help.

This forum post has a bit more info on how Unreal seems to deal with colours. I think it may have something to do with sRGB values and normal RGB values not matching correctly.