Is it possible to measure light absorbance for analysis of lead concentration without photospectrophotmeter
Another possibility is the grease spot photometer (aka Bunsen photometer) German Wiki page. This can be homemade, you need a piece of paper, some wax or oil, two light sources, a meter stick and for the measurement of solutions also some e.g. cardboard to shield unwanted light. Also the darker the room, the better.

The underlying idea is that light intensity from two different sources can be compared (and found to be equal) with a paper with a grease (waxed) spot: the spot will vanish when as much light is transmitted through the spot as reflected around. 

If you move a light source to achieve this condition, you can conclude relative intensities from the distance (intensity goes 1 / d² with d the distance from the respective light source). 

Here's a youtube video demonstrating this: https://www.youtube.com/watch?v=sgZdl4qRa48



How to measure photometrically

so schematically we have:

o--U----|----o

+---d---+


with light sources o, cuvette U and the spotted paper |. Measure distance $d$ between equal intensity paper position and the light source with the cuvette. 

We have $I_{transmitted} \sim \frac{1}{d^2}$

Next, a calibration series is acquired as usual: blank (which serves as $I_0$) and concentrations over the calibration range. Almost as usual:

$$E = -\lg \frac{I}{I_0} \sim \varepsilon l c$$
$$-\lg \frac{d_0^2}{d^2} = b c$$ 
$$\lg d = a + b' c$$ 

$a$ and $b$ are determined by calibration - I use here $a$ instead of $2 \lg d_0$ because several choices are possible and in general the fitted value should be used rather than the theoretical one since it includes some effects in which practice differs from theory (e.g. differences between % transmission in the grease spot from % reflection outside).

Standard addition instead of calibration would be possible as well.