How to Stain a Microscope Slide

By Editorial Team

Updated July 21, 2017

How to Stain a Microscope Slide. The use of stain on microscope slides is common. There are almost endless varieties of stains that can be used on slides. Stains are used to illuminate certain parts of a specimen on a slide. They can also be used to reveal particular substances that may otherwise be invisible. If you work with microscopes, follow these steps to learn how to stain a microscope slide.

Prepare a wet mount slide as you normally would.

Use an eyedropper to collect a drop or two of your stain from its bottle.

Place a single drop of stain on the outer edge of the cover slip on top of your slide. You can place the stain on either edge of the two ends of the cover slip.

Tear off a small piece of a paper towel. Set the paper towel against the opposite end of the cover slip, as close to the edge as possible. The paper towel will act as a magnet, pulling the stain underneath the cover slip.

Wait until all of the stain has been pulled in between the cover slip and the slide. The stain should completely cover the specimen on the slide. If it does not, add another drop of stain to the edge of the cover slip.

Remove the piece of paper towel and place the slide on the viewing tray of the microscope.

Clean the slide and cover slip when you are finished examining the specimen. This must be done gently, as cover slips are quite fragile. Use warm, soapy water and allow everything to air dry. Make sure all the stain has been removed before putting the slide and cover slip away.


Iodine is one of the most common stains used on microscope slides and also the easiest stain to obtain. It can be used to color a variety of flora and fauna specimens. Stains are most often used by students and hobbyists to give contrast and definition to different types of cells and to reveal the presence of bacteria. Professional scientists may use stains to be able to see DNA or molecules.


If you are planning to stain a microscope slide, do not create a petroleum jelly seal for it until after you have applied the stain. Stain will not be able to cross a petroleum jelly seal.

Items you will need

  • Stain of your choice

  • Small piece of paper towel

  • Cover slip

  • Flat glass slide