Just Another Question About Grills On The US Stamps...

Probably just many others here, I came accross on the 3c 1869 (#114) on which was impossible to find any trace of the grill... I have a couple of them now... fluid, uv 365nm, led... all - nothing.

My question is:

is it also possible that on other US issues (for example: 1861) I can miss the grill so easy? Or this "hidden" grill, almost or at all invisible, appear only on pictorials 1869, probably made by purpose, because missing of the grill make them scarce?

For example here: do I need to use all the lights and fluids to detect a possible grill on this stamp, or grill on it will be so transparent that it will be easy visible, in the case if they exist?

Can't tell for sure which one, but this looks like it might be one of the Banknote issues. If so, they began as grilled stamps, but immediately started appearing both with and without grill. Often the grill when present is faint. So if you have one that might be grilled and you want to be sure, dip it.

Hi, it looks to me that there are no grill at all just soft porous paper.

Thank you for the advice, Essayk.

Gladiators001, thank you for the expertize!