Dancqu, can you say more about the Ilford test?
Is it a published formula like Kodak's HT-2 or is
it a packaged product? If it is a formula, could
you post the formula here? Thanks!

From the; Ilford Manual of Photography, 5th Edition,
1958. Formula; 1% solution of silver nitrate.

I allow the staggered drops three minutes then blot.
Examine immediately after. Or, the paper may be
washed. With excess silver nitrate removed the
spots will not darken. Dan