Do you own a piece of AN glass?

If you do make the following test:

Put the glass in contact with something you can put a magnifier on, a good item would be a page with printed text, small types are best. Use the magnifier to look through the AN glass at the text. You will see that the small letters are being broken up and fall apart.

What do you think happens to the details in your negative?

Now look at your hand through the AN glass, hold it approx 1" from your hand. Is the image you see diffused or sharp? That is exactly what AN does to your negative, it makes it unsharp. The test with your hand is an exaggeration of the test with small type.

AN glass is made by treating the surface of Soda lime glass with an acid. The acid starts to deteriorate the glass, and in the process create "millions" of small craters, which in return makes the formation of Newton rings very difficult.

Now look at your standard piece of negative glass from the edge. Is it green? If it is green it is most likely soda lime glass. Soda lime glass is produced by pouring liquid glass on a surface of liquid lead (very hot but not as hot as the liquid glass.) or it is produced by extrusion. Neither float glass or extruded glass have a completely even surface. In fact it is wavy. Waves in a reflective surface creates a distorted image, just think of a chrome car bumper.

How much did you pay for your camera lens? Probably well over $1,000 and the same for your enlarger lens. Many photographers have paid 6-7,000 for the camera lens and at least $1500 for their enlarging lens.

Why are lenses so expensive? Because they are hard to make and use rare glasses, with hard to apply rare surface coatings.

Knowing about the properties of the green Soda lime glass would you insert a piece of the green soda lime glass between your shooting lens and your film?

I think not! So why would you use the green soda lime glass between your negative and your enlarging lens?

Really it makes no sense to spend thousands of dollars on expensive lenses, that precisely is expensive because they are made with rare clear glasses, which are polished to very small tolerances and coated to avoid reflections.

The negative glasses sold by Jensen-Optical / DURST-PRO-USA is matching the best enlarging lenses.

We use SCHOTT glass.
Each sheet of negative glass is polished to absolute parallelism and then coated with an AR coating to reduce Newton rings and to increase light transmission to 99.9%. The coating also achieves less internal reflection in the enlarger and sharper images with better definition and contrast.