passing a localscript variable into a server script through remote event ?

so i have been trying to make a script that changes your trail colour (through remote event), however when i try to set the colour for the trail i get an error saying attemp to index nil with ImageColor3, i understand why it is happening, however i am unsure how to fix it, the code below is what i have so far.

my sever script

local ReplicatedStorage = game:GetService("ReplicatedStorage")

local event = ReplicatedStorage:WaitForChild("lightningcolor")

local function colour(player)
	
	player.Character.Head.trailOuter.Color = ColorSequence.new(_G.colourDisplay.ImageColor3)
	player.Character.Head.trailInner.Color = ColorSequence.new(_G.colourDisplay.ImageColor3)
	player.Character.Head.trailLight.Color = ColorSequence.new(_G.colourDisplay.ImageColor3)
	player.Character.Head.lightningParticle.Color = ColorSequence.new(_G.colourDisplay.ImageColor3)

	player.Character.UpperTorso.trailOuter.Color = ColorSequence.new(_G.colourDisplay.ImageColor3)
	player.Character.UpperTorso.trailInner.Color = ColorSequence.new(_G.colourDisplay.ImageColor3)
	player.Character.UpperTorso.trailLight.Color = ColorSequence.new(_G.colourDisplay.ImageColor3)
	player.Character.UpperTorso.lightningParticle.Color = ColorSequence.new(_G.colourDisplay.ImageColor3)

	player.Character.RightUpperLeg.trailOuter.Color = ColorSequence.new(_G.colourDisplay.ImageColor3)
	player.Character.RightUpperLeg.trailInner.Color = ColorSequence.new(_G.colourDisplay.ImageColor3)
	player.Character.RightUpperLeg.trailLight.Color = ColorSequence.new(_G.colourDisplay.ImageColor3)
	player.Character.RightUpperLeg.lightningParticle.Color = ColorSequence.new(_G.colourDisplay.ImageColor3)

	player.Character.RightUpperArm.trailOuter.Color = ColorSequence.new(_G.colourDisplay.ImageColor3)
	player.Character.RightUpperArm.trailInner.Color = ColorSequence.new(_G.colourDisplay.ImageColor3)
	player.Character.RightUpperArm.trailLight.Color = ColorSequence.new(_G.colourDisplay.ImageColor3)
	player.Character.RightUpperArm.lightningParticle.Color = ColorSequence.new(_G.colourDisplay.ImageColor3)

	player.Character.RightHand.trailOuter.Color = ColorSequence.new(_G.colourDisplay.ImageColor3)
	player.Character.RightHand.trailInner.Color = ColorSequence.new(_G.colourDisplay.ImageColor3)
	player.Character.RightHand.trailLight.Color = ColorSequence.new(_G.colourDisplay.ImageColor3)
	player.Character.RightHand.lightningParticle.Color = ColorSequence.new(_G.colourDisplay.ImageColor3)

	player.Character.RightFoot.trailOuter.Color = ColorSequence.new(_G.colourDisplay.ImageColor3)
	player.Character.RightFoot.trailInner.Color = ColorSequence.new(_G.colourDisplay.ImageColor3)
	player.Character.RightFoot.trailLight.Color = ColorSequence.new(_G.colourDisplay.ImageColor3)
	player.Character.RightFoot.lightningParticle.Color = ColorSequence.new(_G.colourDisplay.ImageColor3)

	player.Character.LeftUpperLeg.trailOuter.Color = ColorSequence.new(_G.colourDisplay.ImageColor3)
	player.Character.LeftUpperLeg.trailInner.Color = ColorSequence.new(_G.colourDisplay.ImageColor3)
	player.Character.LeftUpperLeg.trailLight.Color = ColorSequence.new(_G.colourDisplay.ImageColor3)
	player.Character.LeftUpperLeg.lightningParticle.Color = ColorSequence.new(_G.colourDisplay.ImageColor3)

	player.Character.LeftUpperArm.trailOuter.Color = ColorSequence.new(_G.colourDisplay.ImageColor3)
	player.Character.LeftUpperArm.trailInner.Color = ColorSequence.new(_G.colourDisplay.ImageColor3)
	player.Character.LeftUpperArm.trailLight.Color = ColorSequence.new(_G.colourDisplay.ImageColor3)
	player.Character.LeftUpperArm.lightningParticle.Color = ColorSequence.new(_G.colourDisplay.ImageColor3)

	player.Character.LeftHand.trailOuter.Color = ColorSequence.new(_G.colourDisplay.ImageColor3)
	player.Character.LeftHand.trailInner.Color = ColorSequence.new(_G.colourDisplay.ImageColor3)
	player.Character.LeftHand.trailLight.Color = ColorSequence.new(_G.colourDisplay.ImageColor3)
	player.Character.LeftHand.lightningParticle.Color = ColorSequence.new(_G.colourDisplay.ImageColor3)

	player.Character.LeftFoot.trailOuter.Color = ColorSequence.new(_G.colourDisplay.ImageColor3)
	player.Character.LeftFoot.trailInner.Color = ColorSequence.new(_G.colourDisplay.ImageColor3)
	player.Character.LeftFoot.trailLight.Color = ColorSequence.new(_G.colourDisplay.ImageColor3)
	player.Character.LeftFoot.lightningParticle.Color = ColorSequence.new(_G.colourDisplay.ImageColor3)

end

event.OnServerEvent:Connect(colour)

MY localScript

local colourWheel = script.Parent:WaitForChild("ColourWheel")
local wheelPicker = colourWheel:WaitForChild("Picker")

local darknessPicker = script.Parent:WaitForChild("DarknessPicker")
local darknessSlider = darknessPicker:WaitForChild("Slider")
_G.colourDisplay = script.Parent:WaitForChild("ColourDisplay")

local replicatedstorage = game:GetService("ReplicatedStorage")
local event  = replicatedstorage:WaitForChild("lightningcolor")
local uis = game:GetService("UserInputService")

local player = game.Players.LocalPlayer
local buttonDown = false
local movingSlider = false


local function updateColour(centreOfWheel)
	
	
	local colourPickerCentre = Vector2.new(
		colourWheel.Picker.AbsolutePosition.X + (colourWheel.Picker.AbsoluteSize.X/2),
		colourWheel.Picker.AbsolutePosition.Y + (colourWheel.Picker.AbsoluteSize.Y/2)
	)
	local h = (math.pi - math.atan2(colourPickerCentre.Y - centreOfWheel.Y, colourPickerCentre.X - centreOfWheel.X)) / (math.pi * 2)
	
	local s = (centreOfWheel - colourPickerCentre).Magnitude / (colourWheel.AbsoluteSize.X/2)
	
	local v = math.abs((darknessSlider.AbsolutePosition.Y - darknessPicker.AbsolutePosition.Y) / darknessPicker.AbsoluteSize.Y - 1)
	
	
	_G.hsv = Color3.fromHSV(math.clamp(h, 0, 1), math.clamp(s, 0, 1), math.clamp(v, 0, 1))
	
	
	_G.colourDisplay.ImageColor3 = _G.hsv
	darknessPicker.UIGradient.Color = ColorSequence.new{
		ColorSequenceKeypoint.new(0, _G.hsv), 
		ColorSequenceKeypoint.new(1, Color3.new(0, 0, 0))
	}
	event:FireServer()
	

	
end


colourWheel.MouseButton1Down:Connect(function()
	buttonDown = true
end)

darknessPicker.MouseButton1Down:Connect(function()
	movingSlider = true
end)


uis.InputEnded:Connect(function(input)
	
	if input.UserInputType ~= Enum.UserInputType.MouseButton1 then return end
	
	buttonDown = false
	movingSlider = false
	_G.colourDisplay.Visible = false
end)


uis.InputChanged:Connect(function(input)
	
	if input.UserInputType ~= Enum.UserInputType.MouseMovement then return end
	
	
	local mousePos = uis:GetMouseLocation() - Vector2.new(0, game:GetService("GuiService"):GetGuiInset().Y)
	
	local centreOfWheel = Vector2.new(colourWheel.AbsolutePosition.X + (colourWheel.AbsoluteSize.X/2), colourWheel.AbsolutePosition.Y + (colourWheel.AbsoluteSize.Y/2))
	
	local distanceFromWheel = (mousePos - centreOfWheel).Magnitude
	
	
	if distanceFromWheel <= colourWheel.AbsoluteSize.X/2 and buttonDown then
		
		wheelPicker.Position = UDim2.new(0, mousePos.X - colourWheel.AbsolutePosition.X, 0, mousePos.Y - colourWheel.AbsolutePosition.Y)
		_G.colourDisplay.Visible = true
		_G.colourDisplay.Position = UDim2.new(0.750, mousePos.X - colourWheel.AbsolutePosition.X, -0.02, mousePos.Y - colourWheel.AbsolutePosition.Y )

		
	elseif movingSlider then
		
		darknessSlider.Position = UDim2.new(darknessSlider.Position.X.Scale, 0, 0, 
			math.clamp(
			mousePos.Y - darknessPicker.AbsolutePosition.Y, 
			0, 
			darknessPicker.AbsoluteSize.Y)
		)	
	end
	
	
	updateColour(centreOfWheel)
end)

Hi gamer!

I think your problem here is that you're changing the value on the client. When you change a value from the client, the server doesn't notice the change and do nothing because the change as been made locally and not by the server.

What you could do is, you could move your updateColour function to a server-sided script and use a remote event to communicate.

You could also use a remote function;

— Fire the function from the server to the client and return the color value, however i don't think you shouldn't do that this way because you should NEVER trust the client.

Remote Function and Event here! Click me :)

hello thankyou for your reply, i fixed it , it was just a spelling error :D