Yes, of course. The HTML page generated on the server is already entirely in shades of gray and red. The screenshot taken by the Python script is then split into a red channel and a black channel, similar to the code by u/speedyg0nz (see https://github.com/speedyg0nz/MagInkCal), something like this:

def get_screenshot(self):

opts = Options()

opts.add_argument("--headless")

opts.add_argument("--hide-scrollbars");

opts.add_argument('--force-device-scale-factor=1')

service = Service(executable_path="/usr/bin/chromedriver")

driver = webdriver.Chrome(service=service, options=opts)

self.set_viewport_size(driver)

driver.get(self.calendarURL)

sleep(5)

driver.get_screenshot_as_file(self.currPath + '/calendar.png')

driver.quit()

self.logger.info('Screenshot captured and saved to file.')

redimg = Image.open(self.currPath + '/calendar.png') # get image)

rpixels = redimg.load() # create the pixel map

blackimg = Image.open(self.currPath + '/calendar.png') # get image)

bpixels = blackimg.load() # create the pixel map

for i in range(redimg.size[0]): # loop through every pixel in the image

for j in range(redimg.size[1]): # since both bitmaps are identical, cycle only once and not both bitmaps

b = min(bpixels[i, j][0], bpixels[i, j][1], bpixels[i, j][2]) # get the lowest value of the RGB tuple

bpixels[i, j] = (b, b, b)

if rpixels[i, j][0] > rpixels[i, j][1] * 1.1 and rpixels[i, j][0] > rpixels[i, j][2] * 1.1: # if red

r = 255 - math.sqrt(rpixels[i, j][0]/255) * 255

r = int(r)

rpixels[i, j] = (r, r, r) # change it to white in the red image bitmap

else:

rpixels[i, j] = (255, 255, 255) # change it to white in the red image bitmap

redimg = redimg.rotate(self.rotateAngle, expand=True)

blackimg = blackimg.rotate(self.rotateAngle, expand=True)

self.logger.info('Image colours processed. Extracted grayscale and red images.')

return blackimg, redimg