Mandelbrot set in Excel VBA Code

Public Sub drawMandelbrotBW()
    Sheet1.Activate
    ActiveSheet.Cells(1, 1).Select
    Dim width As Integer
    Dim height As Integer
    Dim max As Integer
    Dim Row As Integer
    Dim Col As Integer
    Dim black As Long

    width = 1920
    height = 1080
    max = 30
    black = RGB(0, 0, 0)

    Dim c_re As Double
    Dim c_im As Double
    Dim x As Double
    Dim y As Double
    Dim iterations As Integer
    Dim x_new As Double
    Dim color_val As Double

    For Row = 1 To height
        For Col = 1 To width
            c_re = (Col - width / 2) * 4 / width
            c_im = (Row - height / 2) * 4 / width
            x = 0
            y = 0
            iterations = 0
            Do While (x ^ 2 + y ^ 2) < 4 And iterations < max
                x_new = x ^ 2 - y ^ 2 + c_re
                y = 2 * x * y + c_im
                x = x_new
                iterations = iterations + 1
            Loop
            If iterations < max Then
                color_val = 255 - (iterations * 8.5)
                Cells(Row, Col).Interior.Color = RGB(color_val, color_val, color_val)
            Else
                Cells(Row, Col).Interior.Color = RGB(0, 0, 0)
            End If
        Next Col
    Next Row
End Sub

Public Sub drawMandelbrotColor()
    Sheet1.Activate
    ActiveSheet.Cells(1, 1).Select
    Dim width As Integer
    Dim height As Integer
    Dim max As Integer
    Dim Row As Integer
    Dim Col As Integer
    Dim black As Long

    width = 1920
    height = 1080
    max = 40
    black = RGB(0, 0, 0)

    Dim c_re As Double
    Dim c_im As Double
    Dim x As Double
    Dim y As Double
    Dim iterations As Integer
    Dim x_new As Double
    Dim color_val As Double
    Dim pallete(40) As Long
    Call initializePallete(pallete, max)

    For Row = 1 To height
        For Col = 1 To width
            c_re = (Col - width / 2) * 4 / width
            c_im = (Row - height / 2) * 4 / width
            x = 0
            y = 0
            iterations = 0
            Do While (x ^ 2 + y ^ 2) < 4 And iterations < max
                x_new = x ^ 2 - y ^ 2 + c_re
                y = 2 * x * y + c_im
                x = x_new
                iterations = iterations + 1
            Loop
            If iterations < max Then
                Cells(Row, Col).Interior.Color = pallete(iterations)
            Else
                Cells(Row, Col).Interior.Color = RGB(0, 0, 0)
            End If
        Next Col
    Next Row
End Sub

Public Sub initializePallete(pallete() As Long, max As Integer)
    colorchunks = max / 4


    c1R = 0
    c1G = 7
    c1B = 100

    c2R = 32
    c2G = 107
    c2B = 203

    c3R = 237
    c3G = 255
    c3B = 255

    c4R = 255
    c4G = 170
    c4B = 0

    c5R = 0
    c5G = 2
    c5B = 0

    r = (c2R - c1R) / colorchunks
    g = (c2G - c1G) / colorchunks
    b = (c2B - c1B) / colorchunks

    For i = 0 To colorchunks
        pallete(i) = RGB(c1R, c1G, c1B)
        c1R = c1R + r
        c1G = c1G + g
        c1B = c1B + b
    Next

    r = (c3R - c2R) / colorchunks
    g = (c3G - c2G) / colorchunks
    b = (c3B - c2B) / colorchunks
    For i = colorchunks To colorchunks * 2
        pallete(i) = RGB(c2R, c2G, c2B)
        c2R = c2R + r
        c2G = c2G + g
        c2B = c2B + b
    Next

    r = (c4R - c3R) / colorchunks
    g = (c4G - c3G) / colorchunks
    b = (c4B - c3B) / colorchunks
        MsgBox (CStr(r) + " " + CStr(g) + " " + CStr(b))
    For i = (colorchunks * 2) To (colorchunks * 3)
        pallete(i) = RGB(c3R, c3G, c3B)
        c3R = c3R + r
        c3G = c3G + g
        c3B = c3B + b
    Next

    r = (c5R - c4R) / colorchunks
    g = (c5G - c4G) / colorchunks
    b = (c5B - c4B) / colorchunks
    For i = colorchunks * 3 To colorchunks * 4
        pallete(i) = RGB(c4R, c4G, c4B)
        c4R = c4R + r
        c4G = c4G + g
        c4B = c4B + b
    Next
End Sub