Someone told me to extract developer concentrate with a syringe and drop a glass marble into the bottle each time to displace the air. That way the bottle stays full...just gets heavier as it gets empty.

I started to wonder what mystery glass marbles are made of now from China...leaded glass?

Paper neg question, if that's ok...I saw references to it here.

Considering spectral sensitivity of graded vs. VC paper, do they 'look' different? Graded is primarily blue sensitive, at least the brands I downloaded graphs for.

Does the narrow spectrum of graded lend itself better for non-achromat/non-APO experimental lenses, like a meniscus?

And if one uses paper neg, what kind of contrast can one get? I read that paper has much less range than film.

Thank you

Holland MI