What is the difference between the color of the circuit board solder resist oil?

What you see is solder mask ink. No line ink. It looks a bit dark. The color of the solder resist ink is white, yellow, black, red, blue, and has a clear ink. The most common is green ink.
There is no strict difference in color! This is just the habit of individual manufacturers or according to customer requirements!
(1) Liquid photosensitive ink:
Liquid photographic inks are a special type of ink that can be printed on a complete plate without a plate. After development, the photosensitive cure of the ink coating can be treated by etching, plating, and electrophoretic filling. Suitable for small batch, multi-variety, personalized and high-precision product production.
(2) UV solder mask ink:
It is suitable for the manufacture of solder-resistant patterns for steel printed circuit boards. It has a fast photocuring speed, good heat resistance and strong adhesion. It meets the requirements of single-sided and double-sided boards. If the viscosity is very high, it can be diluted with a small amount of special diluent, but the dose should not exceed 5% of the amount of ink used.