Sounds like it is treated wood (for termites) One of the common products is blue like windex, but the wood costs more.
The presence of thick cell wall. Gram positives have a thick cell wall and remain blue. Gram negatives have a thin cell wall where the blue stain washes out and then will stain pink with the counter stain.
new methylene blue
Phytoplankton absorb red and blue light, but reflect green light. Therefore, the presence and amount of phytoplankton can indicate the health of the ocean.
To indicate a presence of free residual oxygen.
Stain with basic dyes cytoplasm shows blue precipitates
Iodine is used to indicate the presence of starch. When iodine comes into contact with starch, it forms a dark blue-black complex, providing a visual indicator of the presence of starch in a biological sample.
litmus paper indicates wether a substance is an acid or a base if it is an acid the paper is turns red, if base it turns blue
methelyn blue
Bromthymol blue is used as an indicator to detect the presence of carbon dioxide (CO2) in a solution. It changes color in the presence of acidic conditions, which can indicate the presence of CO2 as it forms carbonic acid when dissolved in water.
Adding iodine to the solution will turn it a deep blue which indicate presence of polysaccharides.
The iodine test can indicate the presence of starch in food samples. When iodine is added to a sample containing starch, it will turn blue-black in the presence of starch. This color change is used as a visual indicator for the presence of starch in the food sample.
The counter or secondary stain used in the acid-fast stain technique is methylene blue.