I spent part of the day today spinning photoresist. Photoresists are light sensitive chemicals used

I spent part of the day today spinning photoresist. Photoresists are light sensitive chemicals used in photolithography. They are spun onto the sample at high speeds, using a tool like the one in the picture, to ensure an even coat. Yellow lighting is used in rooms dedicated to resist application and processing to prevent it from getting exposed. Once the resist is applied, a pattern can be transferred to your sample by exposing only certain areas to light.