It is no secret that scary stories like the ones you see here are full of blood. From Necrosleep to Blind Date, blood is a creepypasta's middle name.
It is also no secret that color is vital in any story. Like a soundtrack, it sets the mood. Descriptions of bright lighting can suggest an upbeat feeling, while dark tones can suggest the opposite.
So how can the color of blood make a difference? Imagine this: A man creeps down an alley, and sees his wife's corpse, bleeding from the stomach. The dark color of the blood, maroon or oxblood, for instance, suggests the sadness that the man feels as a result of this tragic scene.
Now, imagine this modified version of the scene: The man sees the same scene, but with something else-his wife moaning and fidgeting, barely alive, with some hope of living. The man gets out his phone and begins to call 911. Afterward, he prays that help arrives in time. How does this relate to the blood color? It would be best to make the blood bright red, like scarlet or rose red. This would display how pulse-raising this scene is.
So yeah, that's how blood color makes a big difference in a scene. Hope this bit of advice helps, and bye.