Darkroom lightmeter

[adesortis]

Dear friends, I am novel to this field. I would like to assemble a tool to be used in the darkroom during photographic paper printing. Usually an enlarger is used, that projects the negative film image to the photographic paper. It is of great interest to measure the amount of light in very small portions of the projected image, because the grey levels on the developed image strongly depend on the light level.

Thus, I was planning to use the following items:
1) Adafruit VEML7700 Lux Sensor - I2C Light Sensor - STEMMA QT / Qwiic PID: 4162
2) Adafruit BH1750 Light Sensor - STEMMA QT / Qwiic PID: 4681
3) Adafruit TSL2591 High Dynamic Range Digital Light Sensor - STEMMA QT PID: 1980
4) Adafruit ESP32-S2 TFT Feather - 4MB Flash, 2MB PSRAM, STEMMA QT PID: 5300
5) Lithium Ion Polymer Battery Ideal For Feathers - 3.7V 400mAh PID: 3898
6) STEMMA QT / Qwiic JST SH 4-Pin Cable - 400mm long PID: 5385

I need your help to select one of the Items 1), 2) or 3). I need great precision, while the measurement range is not critic, because usually the light level is in the range (0-5000 lux). Attached please find a sketch of the project. Any suggestion is appreciated!
Thank you very much for your attention!
Adriano

[adafruit_support_bill]

For highest resolution, it looks like the TSL2591 would be the way to go. But the VEML7700 is very good also. Their datasheets use different measurement units, so it is difficult to make a direct comparison. The TSL2591 has a resolution of .004uW/cm^2 (4000K white light). The VEML7700 claims a resolution of .0036 lux.

There is no direct conversion from uW/cm^s to lux - since lux assumes a certain spectral distribution. But a rough estimate would put the TSL2591 resolution at about .0017 lux.

The BH1750 comes in a distant third wit a resolution of only 0.4 lux.

[adesortis]

Thank you so much for your help!