4. Demo

Two absorbance measurements (A1 and A2) of the same 15 SPF sunscreen will be used for this demo (demo_beforeUVexposure.csv and demo_afterUVexposure.csv).

1. First download the files and import the module

import photoprotectionpy as pppy
import numpy as np
import pandas as pd

2. Import the data from the csv file

data_before = np.array(pd.read_csv('demo_beforeUVexposure.csv'))
data_after = np.array(pd.read_csv('demo_afterUVexposure.csv'))

3. Initial in vitro SPF with the ispf module

SPFi = pppy.ispf(data_before)

This results in an SPFi_A1 = 15.7895 and SPFi_A1 = 15.3814.

4. C value determination with the adjspf module

C = pppy.adjspf(data_before, mode = 'calc', values = [15], batch = True)

Or, if batch = false:

C = pppy.adjspf(data_before, mode = 'calc', values = [15, 15], batch = False)

This results in C_A1 = 0.9809 and C_A2 = 0.9905.

5. UVA-PF₀ determination with uvapf module

UVA_PF0 = pppy.uvapf(data_before, C = [0.9809, 0.9905])

This results in UVA-P_{0, A1} = 5.3485 and UVA-P_{0, A2} = 5.3664.

6. UV exposure dose with uvdose

UVdose = pppy.uvdose([5.3485, 5.3664])

This results in a UVdose_A1 = 6.4183 J/cm² and UVdose_A2 = 6.4397 J/cm².

7. UVA-PF after UV exposure

UVA-PF = pppy.uvapf(data_after, C = [0.9809, 0.9905])

This results in UVA-PF_A1 = 5.1629 and UVA-PF_A2 = 5.1801.

8. Determination of Critical Wavelength (𝜆_c)

CW = criticalwave(data_after)

This results in a 𝜆_{c, A1} = 376 and 𝜆_{c, A2} = 376.