A "Photogram" has been described as a Camera-less photo, which is a very good description.

Basically it is translucent objects simply just placed on some photographic paper which is then exposed as you would for a normal enlargement of a negative instead of having the negative image projected into the paper

Contact prints are similar in some ways to a photogram except the negative is not projected (enlarged) on to the photo paper but placed in direct CONTACT with the photo paper.

As it is not enlarged the resulting print is actually full size, the size of the negative, which will make the final print very small.

What I do is to scan a negative, enlarge it to the size I want the print, print it on acetate, or maybe draw on the acetate, and then expose the photo paper underneath

Platinum prints are like a normal Black and White enlargement but instead of using the "Silver Halide" coated photo paper you have to coat the photo paper in a Platinum solution and you can then enlarge and expose the negative.

This light sensitive solution gives a much finer and creamy tonal range than the normal Black and White paper

A "Cyanotype" is made very much in the way a "CONTACT" print is made using full size hand drawn or printed negatives made on acetate and then laid in contact with normal paper that I have coated with a light sensitive chemical that turns blue when exposed and processed

"Liquid Light" is a new thing I am playing with, very similar to Cyanotypes in that you coat normal paper with a light sensitive chemical and then expose in the "Contact" way using translucent objects, (like a "Photogram") or full size drawn or printed acetate negatives, (like a "Contact" print) or by projecting a negative as you would for a normal print