Definite E Potential Z Grill

If you are going to use graphite get the pure powder graphite for sticky locks at the hardware store. I don't know what is in pencils anymore but I doubt it is graphite. Or get an art pencil. It is the eraser thing that bothers me more-if you put it on leave it on light touch.

Graphite mixed with clay.

I use pencils fairly often, but I have a very light touch and only use as much as is needed.

i once suggested use of an artists brush to apply a light film of graphite to examine grills and got a snide remark for an answer, imo it is easier to control both the amount used and has no pressure component to worry about. I also think that some practice as suggested is in order.

I can't speak to the motivations behind the snideness but the technique is supposed to only apply graphite to high points and edges, creating a visible contrast. A brush would likely dust everything and not give you the desired contrast.

As to the technique being "advanced", I would submit that any so-called technique that has a deleterious affect on quality is not advanced at all and is closer to a bull-in-a-china-shop approach to grill analysis.

To say that it (this advanced technique) causes no harm, is right up there with the claim that stamp condition doesn't matter when a fancy cancel is involved!

On mint stamps I would agree it is harmful, but on used stamps it is not when properly done. The amount applied is very tiny and safely makes an accurate identification possible.

Almost feels like this discussion should be its own topic.
M&M, brush is an interesting idea, I may try with a few examples to see how that goes. I'm reminded of finger printing which is a similar idea, and that uses a very light duster. I never considered this as an option. I learned the technique from Bill Weiss many years ago. Until his passing, he stands by this method for expertizing, so this is not a rogue approach, I know other expertizers who use and recommend this method as well. Revcollector has it clear also, use only on no gum stamps.
Sinclair2010 - As mentioned before this is a "last resort" not a first place to go. In VERY faint grills, I know of no other method that can provide enhancement. This is not "so-called technique that has a deleterious affect on quality is not advanced at all and is closer to a bull-in-a-china-shop approach to grill analysis". The OP has the edge grills being quite questionable, and difficult to see. A light enhancement, which in the worst case scenario would leave trace graphite on the back of the stamp would be preferable to the inability to definitively identify the stamp, particularly if it is the rare Z-Grill. It's not with risk (especially in clumsy hands), but it's also in many cases, the only way to get such improvement. If you have a better method for grill visibility, please enlighten us.
I've tried working a lot with things like Signoscopes, and other lighting methods, but they have all proved to be useless compared to this examination.

Dipping in lighter fluid helps provided one does not mind breathing in the fumes while looking in many cases, but not all.

The reason that graphite works is because the grill has created texture to the surface of the paper. That texture catches the graphite. It is this very "texture" that will also respond to the careful use of light to enhance the visibility of the grill points. That is an undeniable fact. I dislike the practice and every time it is recommended I speak up. I am under no illusion that I can change the minds of certain individuals but I do think that I can have an affect on those that are not set in there ways.