Nicholas,

Your test shows even gray density over a wide range from 1s to 256s, which is great news for Ilford users.

However, did you also test for contrast, to see if it was affected by exposure time?

Thanks.

- Thomas

Quote Originally Posted by Nicholas Lindan View Post
My experiments show very little to no reciprocity failure with Ilford MGIV RC. I'm sure it holds for the rest of the Ilford range.

http://www.darkroomautomation.com/su...ermittency.pdf

As noted in the application note, the range of exposure times in the darkroom is very narrow - 4 seconds to 64 seconds is equivalent to changing the shutter speed on a camera from 1/4th to 1/60th of a second. NBD.

But unless you have some way of precisely measuring light and controlling exposure the whole reciprocity issue is moot.

For color you need to hold exposure time constant if you can.

When changing magnification the ((M + 1)/(m + 1))^2 formula works very, very well -- see the sticky thread at the top of this forum.