Quote Originally Posted by Ryuji
I disagree. Ilford MG4 has very much lower than that speed, more like 2.5 or lower, if you measure it as a negative emulsion. Of course, one of the problem is to develop the emulsion to a g-bar of 0.62 but even if you accept 2 or so, the speed is still very low.
My exposure was using a piece of MGIV cut to fit a Polaroid holder, then placed on the back of my Mamiya RZ67. The meter on the polaroid back was set at 25, and I used a hand held Sekonic spot meter to verify the exposure. My own emulsion was exposed in-camera using the same method. So, I have in-camera comparison exposures.

All exposures were then processed and gave good images of the subject material which was a MacBeth color checker.

The experiment also included Polaroid film, Endura color paper and several other B&W papers. I have only included a small fraction of the data here.