Film developing at relative low temperature

[MattKing]

Thank you for the explanation. I will try it. But I will need a card toned to zone one first. I guess it can be found in eBay.

You don't need any particular tone on the card. It just needs to be an intermediate tone - not deep black, and not bright white. The meter will interpret its luminance as being the light reflected from the standard tone.
A bath towel makes an excellent reference, because it can be used as a reference with texture for other metering purposes.

 

[ags2mikon]

I have used white before. I know it sounds nuts but your meter will interpret it as 18% grey. The 18% grey helps you to visualize better than white or black. Just don't use brightly colored cards. It "may" skew your results due to a difference between the films color response and the meters response. It is also a good idea to focus at infinity for these tests.

 

[MattKing]

your meter will interpret it as 18% grey.

I prefer to use the phrase: "Your meter will tell you how much camera exposure to give it in order for the result to come out as 18% grey".
(Let's just conveniently ignore the fact that for many/most meters, the goal is actually a slightly different percentage of grey)

 

[Bill Burk]

I prefer to use the phrase: "Your meter will tell you how much camera exposure to give it in order for the result to come out as 18% grey".
(Let's just conveniently ignore the fact that for many/most meters, the goal is actually a slightly different percentage of grey)

True, it’s intent is to place 18% gray in the tone which gives the illusion of 18% gray when viewed by a person looking at a two dimensional black and white print representation of a three dimensional scene.

That tone isn’t 18% but it looks like it.